RevSpace - User contributions [en-gb]

Photomultipliers

2022-07-10T21:05:07Z

Thomastheo: added direct link to datasheet, which seems to have disappeared off the internet since last update

{{Project
|Name=Photomultipliers
|Picture=Xp2202.jpg
|Status=In progress
|Contact=thomas
|Photomultiplier and experiments with cheap scintillators.
}}

==Background==

For those unfamiliar with photomultipliers, they are vacuum tube device used for detecting and quantifying incredibly tiny amounts of light, even single photons. When incoming photons of sufficient energy strike the end window, they cause electrons to be emitted inside the tube's vacuum by means of the photoelectric effect. These electrons are then amplified by a high potential difference across a cascade of what are called dynodes. An incident photon liberates only a single electron at the photocathode window, but when it is then accelerated into the first dynode by a potential difference, it kicks off a number of electrons through secondary emission, which then accelerate to the next dynode, kicking off even more electrons, and so on. After this process repeats a dozen or so times (for however many dynodes the tube has), that one photon/electron event will have been amplified with enormous gain, up to six orders of magnitude or more, resulting in a signal that can be measured and recorded.

They are commonly used as radiation detectors, optically coupled with a material (scintillator) that produces short pulses of light when hit by ionizing radiation. The benefit over their geiger tube cousins is their sensitivity (depending on the size of the scintillator), their versatility (a scintillator can be chosen that is sensitive to different/specific kind of radiation) and their ability (with a suitable scintillator) to not only count pulses, but also measure their energy, allowing for things like spectroscopy. More than one photomultiplier can be coupled to the same scintillator, making it possible to verify with some certainty that a given signal is actually the result of photon emission in the scintillator, which is great for scientific applications.

==Introduction==

I came across a small lot of old photomultiplier tubes on a Dutch on-line auction site. Besides the usual experiments involving detection of various kinds of ionizing radiation, I’d like to use them to have a look at the properties of some inexpensive and readily available materials that could perhaps be used as a scintillator in place of more specialized, optimized and often expensive scintillators employed in professional instruments. I’ll use this page to document my progress in putting together a suitable high voltage bias supply and voltage divider, as well as a simple peak detector/amplifier, and eventually (hopefully) describe some simple experiments.

==Specifications==

The tubes I bought are chunky 2’’ units, with a bialkali photocathode composition that has a spectral sensitivity specifically designed to correspond well with the emissions of traditional scintillator materials. They seem to be quite high-end, tailored specifically for research applications, so I imagine they will be quite suitable for what I intend to do with them. I have four to play with.

Manufacturer: Amperex (Phillips)

Type: XP2202B

Dynodes: 10

Photocathode material: Bialkali

Window diameter: 52mm

Model: XP2202/FL/B (This refers to these tubes having ‘flying leads’, unlike the tube pictured. I'll upload a picture of the actual tubes when I have time.)

Date of manufacture: 46th week of 1984 (!)

For all other info available on this PMT type, see the general [https://revspace.nl/images/1/1b/3497.pdf datasheet]:

==Old photomultipliers==

As you can see, these tubes are not exactly new, and have apparently been sitting in a dusty university cupboard for over thirty years. My first impulse was to do some research into whether there was still a chance of getting some useful life out of them after all this time. Luckily it seems that PMTs are generally quite reliable devices. As long as you shield them from excessive light exposure when powered, run them within their specification on a suitable regulated power supply, and avoid undue mechanical/thermal stress on the pins and glass envelope, their service life will end up being equal to their shelf life. As far as I’ve been able to gather, the most important factor determining shelf life is the kind of glass used in constructing the envelope. UV-sensitive tubes require an end window made of fused quartz, because conventional glass attenuates light of shorter wavelengths. Tubes used in applications involving thermal shock are generally fashioned from borosilicate glass. If these design constraints are not of significant concern, tubes are usually made with plain old soda lime glass.

So why is this relevant? Surprisingly (to me anyway) it turns out that shelf life is directly related to the ingress of helium gas into the tube. On account of it being tiny and mono-atomic, helium gas will diffuse through the glass envelope, causing the pressure inside to slowly rise until it equals the partial pressure of helium in the air outside. Given normal environmental conditions this partial pressure is quite small (5x10^-6 atmospheres), but it’s nevertheless enough to interfere with proper functioning, leading to undesirable behavior such as after-pulses, or even complete failure of the tube. As it happens, quartz glass is relatively permeable to helium, and so quartz PMTs just don’t have a shelf life that extends much past a decade. After quartz, pyrex/borosilicate are the next most permeable envelope materials, and the least permeable of all is soda lime glass, which happens to be the material used in the construction of the XP2202b. From what I can gather, helium ingress is a very slow process even with borosilicates, and profoundly more so in the case of lime glass, so I have good hope that these tubes are still perfectly usable, with much of their functional life remaining. The actual shelf life you get comes down to the concentration of helium in the storage environment (up to a point anyway, obviously other mechanisms of degradation will eventually start to overtake this particular failure mode) and while I don’t know what kind of cupboard they were kept in, I don’t imagine it was directly next to a hissing dewar of liquid helium. Apparently even a few hours in an atmosphere of pure helium is enough to ruin a quartz tube. I choose to be optimistic and assume that my tubes were stored on a shelf next to the rubiks cubes and spare pocket protectors.

See this [http://www.et-enterprises.com/files/file/technical-information/rp101_effect%20of%20exposure%20to%20helium%20on%20photomultiplier%20performance%20and%20lifetime.pdf paper] on helium permeability of glass envelopes for more information.

An unrelated mention, but if you're reading this you might find it interesting: A common failure mode of helium-neon laser tubes is pretty much exactly the opposite of what is described above. Such laser tubes have a low pressure 10:1 helium-neon fill, but over time the helium will diffuse out of the envelope leading to failure. One way to possibly rejuvenate these tubes is to 'soak' them in an atmosphere of pure helium, thereby encouraging diffusion of the working gas back into the tube, restoring operation.

==Plans==

To-do list:

Everything, really.

Dynode divider

HV bias supply (modified ccfl backlight inverter, or built from scratch)

Peak detector/digitizer

Hamamatsu publishes a fantastic [http://www.hamamatsu.com/resources/pdf/etd/PMT_handbook_v3aE.pdf handbook] on everything related to photomultipliers and their application.

==Scintillators==

Ebay is a great source for relatively inexpensive surplus scintillators of all types. Old soviet doped sodium iodide crystals, modern plastic scintillators, LYSO scintillators, they’re all available. So far I have not been able to find affordable large volume/ surface area scintillators, such as the ‘paddles’ conventionally used for things like muon detectors. This project is meant to be fun, so I’m just not willing to spend piles of money on slabs of plastic. Besides, I think it would instead be fun to try and make a detector/scintillator constructed with more affordable and readily available materials. It certainly doesn’t have to be highly optimized or competitive to be adequate for my purposes.

The first ever scintillator, in use long before the invention of the photomultiplier tube, was silver-activated zinc sulfide. Applied as a thin coating on a screen or membrane, it is used in things like spinthariscopes, fluoroscopes and x-ray photo-cassettes. It’s also responsible for the actual glow emitted by radio-luminescent radium paint (albeit doped with copper, which gives a longer lasting green emission). ZnS screens are inexpensive and available, but due to this compound being quite opaque, they are not useful for constructing high volume detectors. They’re great as alpha probes though, so I will definitely give this a go.

Some other early scintillators were made with various aromatic hydrocarbons, traditionally anthracene, stilbene, and naphthalene. Whereas you won’t find the first two at the corner drugstore, naphthalene is quite commonly available in the form of moth balls. Besides the horrendous smell, there are a number of other downsides, unfortunately. Due to the response of these materials being anisotropic (the amount of light produced by scintillation varies with the angle of incidence of the ionizing radiation) it is not possible to use them in applications where you are looking to determine the energy of any particles you’re detecting (unless the incident radiation is in the form of a collimated beam, but since I don’t have a synchrotron, this is not likely to be relevant to my use case). It’s also quite difficult to grow large transparent crystals from these compounds, which is of course necessary if you want to make practical large volume detectors. One way of getting around that problem is to use a suitable solvent, preferably one that has its own scintillation properties, to make a liquid scintillator.

Liquid scintillators are widely used in physics experiments, with a vast range of liquid cocktails available commercially. I’m not willing to use expensive specifically purified isomers most suitable for scintillation, or particularly nasty solvents such as benzene, so the possible options are quickly whittled down to only a few contenders. The most likely among them is xylene, which is reasonably inexpensive, not excessively hazardous, and happens to be quite suitable in combination with naphthalene.

Surprisingly, another possible contender for a cheap and ubiquitous scintillator is found in regular tonic soda (as in gin-and-tonic soda). Its fluorescent properties are well known to anyone who has ever messed around with a black light, or anyone who’s been to a cheesy night club for that matter. Quinine sulfate, the compound responsible for this effect, apparently does act as a scintillator when exposed to ionizing radiation, although I have no idea of its efficacy, especially at the minuscule mg/L concentrations commonly found in tonic soda. I’m not hopeful, but it’s cheap enough, and in this case failure comes with its own reward, so there’s no reason not to try it.

It is possible nowadays to buy fluors that are used in commercially available scintillator cocktails. Prices for compounds such as PPO (2,5-diphenyloxazole) are quite reasonable on Ebay. Even wavelength shifters (used to convert light emitted by scintillation to a wavelength that more closely matches the sensitivity of your detector) such as POPOP (1,4-bis(5-phenyloxazol-2-yl) benzene) are available relatively cheaply and in small quantities. This is definitely something I would like to try. The problem of finding a suitably pure and safe solvent still remains, however. It might be possible to mix the fluor and/or wavelength shifter with some kind of casting resin, allowing you to pour your own plastic scintillators. This sounds easy in principle, but I expect this to be a little more involved in practice.

==Updates==

This page is a work in progress. I will list major updates here.

17-3-2017: Project started

27-7-2017: Acquired a lab-grade linearly regulated supply that is capable of outputting ultrastable bias voltages from 0 to -2500 volts, so the bias supply is now sorted.

File:3497.pdf

2022-07-10T21:03:53Z

Thomastheo: XP2202 datasheet

== Summary ==
XP2202 datasheet

File:45mmcircle.svg

2018-08-02T11:04:48Z

Thomastheo:

File:Scalpelholder3.svg

2018-07-30T16:38:00Z

Thomastheo:

File:Scalpelholder2.svg

2018-07-30T16:21:09Z

Thomastheo:

File:Scalpelholderone.svg

2018-07-30T15:50:11Z

Thomastheo:

File:Bracket.svg

2018-07-27T11:35:49Z

Thomastheo:

Sleutelkastje

2018-07-23T12:33:20Z

Thomastheo: I do not pray to this god.

{{Project
|Name=Sleutelkastje
|Picture=P1010452.JPG
|Omschrijving=Een kastje voor de spacebike-sleutel
|Status=Completed
|Contact=Sebastius
|Contact2=Juerd
}}

==Bouw==

Hangt aan Doorduino. Een Arduino Nano verzorgt de logica en aansturing solenoid.

Twee mosfets, IRF520N (IRL540N is ook prima mochten ze ooit stuk gaan)
Solenoid uit oude PC kast (bak 'Electromechanisch)
Stripje plexiglas versmolten met chloroform aan het raampje

==Code==
https://github.com/revspace/sleutelkastje

File:Valvebracket2.svg

2018-07-22T17:31:16Z

Thomastheo:

File:Valvebracket.svg

2018-07-22T16:48:24Z

Thomastheo:

File:Geigertubecase.svg

2018-05-30T19:16:18Z

Thomastheo:

File:Strainrelief .svg

2018-05-23T20:54:10Z

Thomastheo:

File:Backplanewithpcbmountsextended.svg

2018-05-23T14:10:18Z

Thomastheo:

File:Backplanesmallwithpcbholes.svg

2018-05-23T11:36:07Z

Thomastheo:

File:Backplane.svg

2018-05-20T18:11:38Z

Thomastheo:

3DPrinter

2018-05-14T17:00:10Z

Thomastheo:

'''Noodupdate 14 mei 2018:''' Deze pagina is hopeloos verouderd en moet eigenlijk ook uitgebreid worden. Wees voor nu op de hoogte (ivm instellingen Cura) dat de printer een update heeft gekregen. Het is een Ultimaker 2 Extended+ geworden.

Revspace heeft sinds vandaag een semi-professionele 3d-printer, de Ultimaker 2 Extended. Vandaag zijn de eerste proef-prints gemaakt, en die kwamen er eigenlijk vanaf de 1e print gewoon goed uit.

[https://ultimaker.com/en/products/ultimaker-2-extended Ultimaker 2 Extended]

Build volume: 223 x 223 x 305 mm
Filament diameter: 2.85 mm

Layer resolutions
Fast: 0.2mm
Nomal: 0.1mm
High: 0.06mm
Ultra high: 0.4mm

3DPrinter

2018-05-14T16:59:48Z

Thomastheo:

{{NewsItem
|Name=3DPrinter
|Date=2015-07-09
|Info=Revspace heeft 'eindelijk' een goede 3d-printer
|Image=
}}

'''Noodupdate 14 mei 2018:''' Deze pagina is hopeloos verouderd en moet eigenlijk ook uitgebreid worden. Wees voor nu op de hoogte (ivm instellingen Cura) dat de printer een update heeft gekregen. Het is een Ultimaker 2 Extended+ geworden.

Revspace heeft sinds vandaag een semi-professionele 3d-printer, de Ultimaker 2 Extended. Vandaag zijn de eerste proef-prints gemaakt, en die kwamen er eigenlijk vanaf de 1e print gewoon goed uit.

[https://ultimaker.com/en/products/ultimaker-2-extended Ultimaker 2 Extended]

Build volume: 223 x 223 x 305 mm
Filament diameter: 2.85 mm

Layer resolutions
Fast: 0.2mm
Nomal: 0.1mm
High: 0.06mm
Ultra high: 0.4mm

Vloer

2018-04-06T16:18:10Z

Thomastheo: /* Aanwezig */

{{Project
|Name = Vloer
|Picture = FF0B8F4A-C2FB-448A-9B4B-B19F272516BF.jpeg
|Omschrijving = Een nieuwe vloer!
|Status = In progress
|Contact = Sebastius
|Contact1 = Juerd
|Contact2 = Maxell
|Contact3 = F0x
|Contact4 = WinSCaP
}}

{{Event
|Name=Vloer leggen
|DateStart=13 Apr 2018 16:00
|InfoLocation=Overgoo 1, Leidschendam
|InfoOpen=16:00
}}

=Het plan=
We gaan in de hoofdruimte en in de keuken de vloer upgraden.

De nieuwe vloer is kliksysteem van PVC-planken. Het komt bovenop de bestaande vloer (linoleum). Rondom moet ruimte vrijgehouden worden (volgens de fabrikant 10 mm) voor uitzetting. Dat werken we af met comprimeerbaar schuim en siliconenkit, of met plinten, zodat er geen vuil in komt. De ambitie is om de vloer netjes af te snijden op precies de juiste plek, dat maakt het kitten veel makkelijk. Omdat het PVC-laminaat wordt gesneden met een hobbymes, in plaats van gezaagd, is het makkelijk om het heel strak te doen.

Om de vloer te kunnen leggen, moeten meubels worden verwijderd. De grote stellingkasten zijn in delen te demonteren, zodat de rest kan blijven staan. Zodra een stukje vloer gelegd is en de randen afgewerkt, kan de kast daar alweer worden opgebouwd. Op die manier hoeven we nooit de ruimte helemaal leeg te halen.

In de hoofdruimte werken we vanaf de kant met het beamerscherm. In de keuken beginnen we aan de kant van het aanrecht.

Bij deuren komen aluminium profielen. Het bestaande aluminiumprofiel bij de lounge moet eraf; misschien is die opnieuw te gebruiken, misschien ook niet.

We hebben momenteel geen vilt of rubber onder meubels, maar om de nieuwe vloer te beschermen doen we dat er wel onder voordat het teruggezet wordt. Met de lasersnijder kunnen we viltplakken op maat snijden voor onder de doppen van de stellingkast.

=Planning=
Er is werk voor ongeveer 10 à 15 mensen, waarvan er 3 bezig zijn met de vloer leggen en de rest met alles eromheen.

==Voorafgaand==
* Laminaat bestellen en in ontvangst nemen
* Gereedschappen verzamelen
* Mensen werven
* Boodschappen bestellen voor VrijwilligersVoer

{|class=wikitable
|valign=top|
==Vrijdag 13 april==
===Aanwezig===
* Sebastius
* Dave_o
* f0x
* Juerd
* Eightdot
* Trashman
* Teun
* thomas
* Jouw naam hier?

===Planning===
Start om 16:00

|valign=top|

==Zaterdag 14 april==
===Aanwezig===
* Sebastius
* Dave_o
* Juerd
* Maxel
* benadski
* eightdot
* kinroy
* Trashman
* Teun
* Jouw naam hier?

===Planning===
* Starten om 11:00

|valign=top|

==Zondag 15 april==
===Aanwezig===
* f0x
* Dave_o
* Boekenwuurm
* Juerd
* Maxell
* benadski
* eightdot
* kinroy
* Jouw naam hier?

===Planning===
*Start om 11:00
|}

=Vrijwilligermanagement=
Uiteraard krijgen alle klussers te eten en drinken. Het bestuur zoekt iemand die inkopen kan doen.

=Gereedschap=
*Breekmesjes
*Laminaathaak
*Rubber hamer (lichter dan we nu hebben)
*Afstandblokjes
*Het standaard laminaatsetje van Ikea

Revfan

2018-03-12T16:55:21Z

Thomastheo:

{{Project
|Name=Revfan
|Picture
|Omschrijving=Automatisch aan- en uitschakelen afzuiging
|Status=Completed
|Contact=Juerd, thomas
}}

Gebouwd op basis van een SHA2017-badge. Source van de app op https://badge.sha2017.org/projects/revfan (je moet <code>__init.py__</code> hebben).

Revfan besluit op basis van de spacestate en luchtkwaliteit (CO2 en luchtvochtigheid) of de afzuiging aan of uit moet. Er wordt een bistabiel relais gepulst bij verandering van het besluit. Het relais is er eentje uit de HFE10-serie en zou motoren tot 5 HP (ca. 16 A) moeten kunnen schakelen, of resistieve belastingen van 50 A. De eerste fancontroller had kuren, deels door neppe mosfets uit China. Versie twee is iets anders ingericht:

De badge wordt gevoed door de 12V adapter via een ouderwetse 7805. Het relais wordt geschakeld door een ULN4003A darlington array. Om er voor te zorgen dat de relaisspoelen niet constant gevoed kunnen worden als de badge crasht, en om back-emf nog verder te minimaliseren, wordt de relais niet direct gevoed van de 12v adapter. In plaats daarvan wordt er via een 500R weerstand een dikke 16V 10000uF condensator opgeladen, welke het energiereservoir is dat de ULN4003A voedt en genoeg kan leveren om de relais een keer te schakelen. De condensator dumpt z'n hele lading over de spoel, waarna er geen noemenswaardige stroom meer kan blijven lopen naar de schakeling, dankzij de 500R weerstand. Als het schakelsignaal weer weg is laadt de elco langzaam (tien seconden oid) weer op. De schakeling kan dus niet meer dan een paar keer per minuut schakelen, maar dat is bij deze toepassing niet erg.

Let op: omdat er enkelpolig geschakeld wordt en dat ofwel de fase ofwel de nul kan zijn (afhankelijk van de orientatie van de schuko), is de fan niet met een contactdoos en contactstop aangesloten, maar vast bedraad.

== Besluitvorming ==

Elke trede in een CO2-waardetabel (ten tijde van schrijven 500, 900, 1200, 1500 PPM) geeft een pluspunt. Elke trede in een luchtvochtigheidstabel (ten tijde van schrijven 34, 38 %) geeft een minpunt. Ook een open space geeft een minpunt. Wanneer het totaal van de plus- en minpunten positief is, wordt de ventilator ingeschakeld. Is de totaalscore negatief, dan wordt ie naar 0 (= uit) geforceerd.

==Aansluitingen controller==
<gallery>
File:Revfancontrollerpinout.png|Pinout van de controller, voor als je 'm weer in elkaar wil zetten.
File:Revfancontroller.jpg|Controllerbordje.
File:Revfanbadge.jpg|Aansluiting badge.

</gallery>

== Zie ook ==

* [[Space3ventilatie]]
* [[CO2MeterHacking]]

Revfan

2018-03-12T16:47:29Z

Thomastheo: /* Pictures/schematics */

{{Project
|Name=Revfan
|Picture
|Omschrijving=Automatisch aan- en uitschakelen afzuiging
|Status=Completed
|Contact=Juerd, thomas
}}

Gebouwd op basis van een SHA2017-badge. Source van de app op https://badge.sha2017.org/projects/revfan (je moet <code>__init.py__</code> hebben).

Revfan besluit op basis van de spacestate en luchtkwaliteit (CO2 en luchtvochtigheid) of de afzuiging aan of uit moet. Er wordt een bistabiel relais gepulst bij verandering van het besluit. Het relais is er eentje uit de HFE10-serie en zou motoren tot 5 HP (ca. 16 A) moeten kunnen schakelen, of resistieve belastingen van 50 A. De eerste fancontroller had kuren, vanwege back-emf van het relais en door neppe mosfets uit China. Versie twee is iets anders ingericht:

De badge wordt gevoed door de 12V adapter via een ouderwetse 7805. Het relais wordt geschakeld door een ULN4003A darlington array. Om er voor te zorgen dat de relaisspoelen niet constant gevoed kunnen worden als de badge crasht, en om back-emf nog verder te minimaliseren, wordt de relais niet direct gevoed van de 12v adapter. In plaats daarvan wordt er via een 500R weerstand een dikke 16V 10000uF condensator opgeladen, welke het energiereservoir is dat de ULN4003A voedt en genoeg kan leveren om de relais een keer te schakelen. De condensator dumpt z'n hele lading over de spoel, waarna er geen noemenswaardige stroom meer kan blijven lopen naar de schakeling, dankzij de 500R weerstand. Als het schakelsignaal weer weg is laadt de elco langzaam (tien seconden oid) weer op. De schakeling kan dus niet meer dan een paar keer per minuut schakelen, maar dat is bij deze toepassing niet erg.

Let op: omdat er enkelpolig geschakeld wordt en dat ofwel de fase ofwel de nul kan zijn (afhankelijk van de orientatie van de schuko), is de fan niet met een contactdoos en contactstop aangesloten, maar vast bedraad.

== Besluitvorming ==

Elke trede in een CO2-waardetabel (ten tijde van schrijven 500, 900, 1200, 1500 PPM) geeft een pluspunt. Elke trede in een luchtvochtigheidstabel (ten tijde van schrijven 34, 38 %) geeft een minpunt. Ook een open space geeft een minpunt. Wanneer het totaal van de plus- en minpunten positief is, wordt de ventilator ingeschakeld. Is de totaalscore negatief, dan wordt ie naar 0 (= uit) geforceerd.

==Aansluitingen controller==
<gallery>
File:Revfancontrollerpinout.png|Pinout van de controller, voor als je 'm weer in elkaar wil zetten.
File:Revfancontroller.jpg|Controllerbordje.
File:Revfanbadge.jpg|Aansluiting badge.

</gallery>

== Zie ook ==

* [[Space3ventilatie]]
* [[CO2MeterHacking]]

Revfan

2018-03-12T16:46:43Z

Thomastheo:

{{Project
|Name=Revfan
|Picture
|Omschrijving=Automatisch aan- en uitschakelen afzuiging
|Status=Completed
|Contact=Juerd, thomas
}}

Gebouwd op basis van een SHA2017-badge. Source van de app op https://badge.sha2017.org/projects/revfan (je moet <code>__init.py__</code> hebben).

Revfan besluit op basis van de spacestate en luchtkwaliteit (CO2 en luchtvochtigheid) of de afzuiging aan of uit moet. Er wordt een bistabiel relais gepulst bij verandering van het besluit. Het relais is er eentje uit de HFE10-serie en zou motoren tot 5 HP (ca. 16 A) moeten kunnen schakelen, of resistieve belastingen van 50 A. De eerste fancontroller had kuren, vanwege back-emf van het relais en door neppe mosfets uit China. Versie twee is iets anders ingericht:

De badge wordt gevoed door de 12V adapter via een ouderwetse 7805. Het relais wordt geschakeld door een ULN4003A darlington array. Om er voor te zorgen dat de relaisspoelen niet constant gevoed kunnen worden als de badge crasht, en om back-emf nog verder te minimaliseren, wordt de relais niet direct gevoed van de 12v adapter. In plaats daarvan wordt er via een 500R weerstand een dikke 16V 10000uF condensator opgeladen, welke het energiereservoir is dat de ULN4003A voedt en genoeg kan leveren om de relais een keer te schakelen. De condensator dumpt z'n hele lading over de spoel, waarna er geen noemenswaardige stroom meer kan blijven lopen naar de schakeling, dankzij de 500R weerstand. Als het schakelsignaal weer weg is laadt de elco langzaam (tien seconden oid) weer op. De schakeling kan dus niet meer dan een paar keer per minuut schakelen, maar dat is bij deze toepassing niet erg.

Let op: omdat er enkelpolig geschakeld wordt en dat ofwel de fase ofwel de nul kan zijn (afhankelijk van de orientatie van de schuko), is de fan niet met een contactdoos en contactstop aangesloten, maar vast bedraad.

== Besluitvorming ==

Elke trede in een CO2-waardetabel (ten tijde van schrijven 500, 900, 1200, 1500 PPM) geeft een pluspunt. Elke trede in een luchtvochtigheidstabel (ten tijde van schrijven 34, 38 %) geeft een minpunt. Ook een open space geeft een minpunt. Wanneer het totaal van de plus- en minpunten positief is, wordt de ventilator ingeschakeld. Is de totaalscore negatief, dan wordt ie naar 0 (= uit) geforceerd.

== Pictures/schematics ==
<gallery>
File:Revfancontrollerpinout.png|Pinout van de controller, voor als je 'm weer in elkaar wil zetten.
File:Revfancontroller.jpg|Controllerbordje.
File:Revfanbadge.jpg|Aansluiting badge.

</gallery>

== Zie ook ==

* [[Space3ventilatie]]
* [[CO2MeterHacking]]

File:Revfancontrollerpinout.png

2018-03-12T16:41:47Z

Thomastheo:

Revfan

2018-03-12T15:57:01Z

Thomastheo:

{{Project
|Name=Revfan
|Picture
|Omschrijving=Automatisch aan- en uitschakelen afzuiging
|Status=Completed
|Contact=Juerd, thomas
}}

Gebouwd op basis van een SHA2017-badge. Source van de app op https://badge.sha2017.org/projects/revfan (je moet <code>__init.py__</code> hebben).

Revfan besluit op basis van de spacestate en luchtkwaliteit (CO2 en luchtvochtigheid) of de afzuiging aan of uit moet. Er wordt een bistabiel relais gepulst bij verandering van het besluit. Het relais is er eentje uit de HFE10-serie en zou motoren tot 5 HP (ca. 16 A) moeten kunnen schakelen, of resistieve belastingen van 50 A. De eerste fancontroller had kuren, vanwege back-emf van het relais en door neppe mosfets uit China. Versie twee is iets anders ingericht:

De badge wordt gevoed door de 12V adapter via een ouderwetse 7805. Het relais wordt geschakeld door een ULN4003A darlington array. Om er voor te zorgen dat de relaisspoelen niet constant gevoed kunnen worden als de badge crasht, en om back-emf nog verder te minimaliseren, wordt de relais niet direct gevoed van de 12v adapter. In plaats daarvan wordt er via een 500R weerstand een dikke 16V 10000uF condensator opgeladen, welke het energiereservoir is dat de ULN4003A voedt en genoeg kan leveren om de relais een keer te schakelen. De condensator dumpt z'n hele lading over de spoel, waarna er geen noemenswaardige stroom meer kan blijven lopen naar de schakeling, dankzij de 500R weerstand. Als het schakelsignaal weer weg is laadt de elco langzaam (tien seconden oid) weer op. De schakeling kan dus niet meer dan een paar keer per minuut schakelen, maar dat is bij deze toepassing niet erg.

Let op: omdat er enkelpolig geschakeld wordt en dat ofwel de fase ofwel de nul kan zijn (afhankelijk van de orientatie van de schuko), is de fan niet met een contactdoos en contactstop aangesloten, maar vast bedraad.

== Besluitvorming ==

Elke trede in een CO2-waardetabel (ten tijde van schrijven 500, 900, 1200, 1500 PPM) geeft een pluspunt. Elke trede in een luchtvochtigheidstabel (ten tijde van schrijven 34, 38 %) geeft een minpunt. Ook een open space geeft een minpunt. Wanneer het totaal van de plus- en minpunten positief is, wordt de ventilator ingeschakeld. Is de totaalscore negatief, dan wordt ie naar 0 (= uit) geforceerd.

== Zie ook ==

* [[Space3ventilatie]]
* [[CO2MeterHacking]]

File:Revfancontroller.jpg

2018-03-12T15:35:06Z

Thomastheo:

File:Revfanbadge.jpg

2018-03-12T15:34:37Z

Thomastheo:

Gigaohmvoltmeter

2017-12-24T10:50:42Z

Thomastheo: /* Why? */

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

==What's in the box?==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

<gallery>
File:Voltmeterinside.jpg|That's all, folks.
</gallery>

==Why?==

It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance this meter draws only 1 nanoamp per volt of deflection. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-24T10:49:46Z

Thomastheo: /* Why? */

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

==What's in the box?==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

<gallery>
File:Voltmeterinside.jpg|That's all, folks.
</gallery>

==Why?==

It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt of deflection. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-24T10:48:51Z

Thomastheo:

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

==What's in the box?==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

<gallery>
File:Voltmeterinside.jpg|That's all, folks.
</gallery>

==Why?==

It's very useful for measuring DC voltages without having to worry about loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt of 'deflection'. I built it to measure the output of the feeble high voltage supplies generally used for geiger counters and photomultipliers.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-24T10:30:50Z

Thomastheo: /* What's in the box */

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

<gallery>
File:Voltmeterinside.jpg|That's all, folks.
</gallery>

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt from the circuit under test. That is sufficiently low to allow measurement of voltage across a geiger tube while it is operating, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

File:Voltmeterinside.jpg

2017-12-24T10:25:28Z

Thomastheo:

Contact

2017-12-21T22:18:06Z

Thomastheo: /* Telefoon */

__NOTOC__
{|
|valign=top|
= Postadres =
Stichting Revelation Space
Vlietweg 15 B0.04
2266 KA Leidschendam
|valign=top|
= Bezoekadres =
Stichting Revelation Space
Overgoo 1
2266 JZ Leidschendam
[[Bezoeken|Route en parkeren...]]
|}
= Online =

* https://revspace.nl/
* revspace@revspace.nl (mailing list van deelnemers en geïnteresseerden)
* board@revspace.nl (mailing list van het [[Bestuur]])
* [[IRC|#revspace op freenode]]
* [https://twitter.com/revspacenl @revspacenl]
* https://www.facebook.com/revspace

= Telefoon =

We zijn bereikbaar via telefoon, maar dit werkt volgens het ouderwetse principe van bellen naar een locatie, in plaats van bellen naar een persoon. Oftewel, je hebt geen idee wie je aan de lijn krijgt; het zou zomaar een willekeurige bezoeker kunnen zijn. Als er al iemand opneemt... En mocht je iemand treffen met een mening, dan is die mening waarschijnlijk niet representatief voor alle deelnemers, of voor de stichting.

+31 (0)63 227 8700 (hoofdruimte)

+31 (0)85 201 7336 (lounge)

Wil je in contact komen met het bestuur, e-mail dan direct naar de betreffende mailinglist (board@revspace.nl).

For the non-dutch speakers among us: If the space is open, your best bet is to call +31 (0)63 227 8700. There is a very good chance that whoever answers will be at least somewhat proficient in English.

= Stichting Revelation Space =

Andere info die je wellicht zocht:

; KvK: 27363894
; Bankrekening zonder spaties: IBAN: NL69ABNA0431158207, BIC: ABNANL2A
; Bankrekening met spaties: IBAN: NL69 ABNA 0431 1582 07, BIC: ABNANL2A

Contact

2017-12-21T22:17:39Z

Thomastheo: /* Telefoon */

__NOTOC__
{|
|valign=top|
= Postadres =
Stichting Revelation Space
Vlietweg 15 B0.04
2266 KA Leidschendam
|valign=top|
= Bezoekadres =
Stichting Revelation Space
Overgoo 1
2266 JZ Leidschendam
[[Bezoeken|Route en parkeren...]]
|}
= Online =

* https://revspace.nl/
* revspace@revspace.nl (mailing list van deelnemers en geïnteresseerden)
* board@revspace.nl (mailing list van het [[Bestuur]])
* [[IRC|#revspace op freenode]]
* [https://twitter.com/revspacenl @revspacenl]
* https://www.facebook.com/revspace

= Telefoon =

We zijn bereikbaar via telefoon, maar dit werkt volgens het ouderwetse principe van bellen naar een locatie, in plaats van bellen naar een persoon. Oftewel, je hebt geen idee wie je aan de lijn krijgt; het zou zomaar een willekeurige bezoeker kunnen zijn. Als er al iemand opneemt... En mocht je iemand treffen met een mening, dan is die mening waarschijnlijk niet representatief voor alle deelnemers, of voor de stichting.

+31 (0)63 227 8700

+31 (0)85 201 7336

Wil je in contact komen met het bestuur, e-mail dan direct naar de betreffende mailinglist (board@revspace.nl).

For the non-dutch speakers among us: If the space is open, your best bet is to call +31 (0)63 227 8700. There is a very good chance that whoever answers will be at least somewhat proficient in English.

= Stichting Revelation Space =

Andere info die je wellicht zocht:

; KvK: 27363894
; Bankrekening zonder spaties: IBAN: NL69ABNA0431158207, BIC: ABNANL2A
; Bankrekening met spaties: IBAN: NL69 ABNA 0431 1582 07, BIC: ABNANL2A

Gigaohmvoltmeter

2017-12-21T19:49:46Z

Thomastheo: /* Operating instructions */

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a pair of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt from the circuit under test. That is sufficiently low to allow measurement of voltage across a geiger tube while it is operating, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-21T19:49:06Z

Thomastheo:

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Multiply reading by 10 for actual voltage value. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt from the circuit under test. That is sufficiently low to allow measurement of voltage across a geiger tube while it is operating, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-21T13:35:36Z

Thomastheo: /* What's in the box */

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading shown on the display ''does'' need to be multiplied by 10x.wo

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt from the circuit under test. That is sufficiently low to allow measurement of voltage across a geiger tube while it is operating, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-21T11:56:55Z

Thomastheo: /* Why */

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading output by the display ''does'' need to be multiplied by 10x.wo

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. Thanks to the gigaohm input impedance, this meter draws only 1 nanoamp per volt from the circuit under test. That is sufficiently low to allow measurement of voltage across a geiger tube while it is operating, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-21T11:53:09Z

Thomastheo: /* What's in the box */

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider consists of a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading output by the display ''does'' need to be multiplied by 10x.wo

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. By using a voltage divider with ridiculous values of 1 gigaohm, the meter draws only 1 nanoamp per volt from the circuit under test. This is sufficiently low to allow measurement of the voltage across a geiger tube while it is in operation, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

Gigaohmvoltmeter

2017-12-21T11:51:17Z

Thomastheo: Created page with "{{Project |Name=Gigaohm Voltmeter |Picture=voltmeter.jpg |Omschrijving= High impedance voltmeter |Status=Completed |Contact=thomas }} ==Important Safety Inform..."

{{Project
|Name=Gigaohm Voltmeter
|Picture=voltmeter.jpg
|Omschrijving= High impedance voltmeter
|Status=Completed
|Contact=thomas
}}

==Important Safety Information==

This meter is '''only''' designed to be used for measuring '''very low current''' moderate to high voltage supplies. There is no input protection whatsoever other than the gigaohm resistor, which is rated for a maximum of 1500VDC. The banana jacks are not meant for high-voltage high-current applications. The isolation is not adequate for safe operation with power supplies capable of delivering anything more than a tickle's worth of current.

==What's in the box==

This is nothing more than a resistive divider and a high impedance voltmeter. The divider is a Dale 1 gigaohm 1.5kv 1% tolerance resistor, and a regular anonymous 100K carbon resistor. Crashjuh supplied a Dynatek 200 millivolt 200 megaohm input impedance panel meter, which is connected across the 100k resistor. Because of the 200mV range, the reading output by the display ''does'' need to be multiplied by 10x.wo

==Operating instructions==

Connect circuit to meter with banana jacks. Turn on meter. Cross fingers. Keep in mind that the banana jacks (and cables) are most likely not rated for the voltages you are using them at, so suspend them off and away from conductive surfaces. Keep in mind that this is a high impedance device, and that whatever you are connecting it to is most likely also a high impedance circuit; Long cables can couple in a lot of noise. To minimize this problem I cobbled together a couple of really short banana-crocodile cables.

==Why==

This voltmeter is useful for measuring DC voltages without loading down the circuit under test. The input impedance of a regular multimeter can sometimes be too much of a burden for circuits incapable of delivering sufficient current to maintain voltage while taking a reading. By using a voltage divider with ridiculous values of 1 gigaohm, the meter draws only 1 nanoamp per volt from the circuit under test. This is sufficiently low to allow measurement of the voltage across a geiger tube while it is in operation, which happens to be the primary reason for building the thing in the first place.

==Can I open it?==

No. There is a gigaohm resistor inside, and it does not like finger grease, Mate spray, or sideways glances. The battery should last forever, provided you turn it off after use.

==It doesn't work==

Put it on my Samla (thomas), and let me know. Thanks!

File:Voltmeter.jpg

2017-12-21T10:56:48Z

Thomastheo:

Contact

2017-12-15T01:26:48Z

Thomastheo: /* Telefoon */

__NOTOC__
{|
|valign=top|
= Postadres =
Stichting Revelation Space
Vlietweg 15 B0.04
2266 KA Leidschendam
|valign=top|
= Bezoekadres =
Stichting Revelation Space
Overgoo 1
2266 JZ Leidschendam
[[Bezoeken|Route en parkeren...]]
|}
= Online =

* https://revspace.nl/
* revspace@revspace.nl (mailing list van deelnemers en geïnteresseerden)
* board@revspace.nl (mailing list van het [[Bestuur]])
* [[IRC|#revspace op freenode]]
* [https://twitter.com/revspacenl @revspacenl]
* https://www.facebook.com/revspace

= Telefoon =

Er is een telefoon, maar die werkt volgens het ouderwetse principe van bellen naar een locatie, in plaats van bellen naar een persoon. Oftewel, je hebt geen idee wie je aan de lijn krijgt; het zou zomaar een willekeurige bezoeker kunnen zijn. Als er al iemand opneemt... En mocht je iemand treffen met een mening, dan is die mening waarschijnlijk niet representatief voor alle deelnemers, of voor de stichting.

+31 (0)63 227 8700

Er is een tweede telefoon in de lounge ([https://revspace.nl/Telefoon Link naar de relevante wikipagina)]: +31 (0)85 201 7336

Wil je in contact komen met het bestuur, e-mail dan direct naar de betreffende mailinglist (board@revspace.nl).

For the non-dutch speakers among us: If the space is open, your best bet is to call +31 (0)63 227 8700. There is a very good chance that whoever answers will be at least somewhat proficient in English.

= Stichting Revelation Space =

Andere info die je wellicht zocht:

; KvK: 27363894
; Bankrekening zonder spaties: IBAN: NL69ABNA0431158207, BIC: ABNANL2A
; Bankrekening met spaties: IBAN: NL69 ABNA 0431 1582 07, BIC: ABNANL2A

Contact

2017-12-15T01:25:36Z

Thomastheo: /* Telefoon */

__NOTOC__
{|
|valign=top|
= Postadres =
Stichting Revelation Space
Vlietweg 15 B0.04
2266 KA Leidschendam
|valign=top|
= Bezoekadres =
Stichting Revelation Space
Overgoo 1
2266 JZ Leidschendam
[[Bezoeken|Route en parkeren...]]
|}
= Online =

* https://revspace.nl/
* revspace@revspace.nl (mailing list van deelnemers en geïnteresseerden)
* board@revspace.nl (mailing list van het [[Bestuur]])
* [[IRC|#revspace op freenode]]
* [https://twitter.com/revspacenl @revspacenl]
* https://www.facebook.com/revspace

= Telefoon =

Er is een telefoon, maar die werkt volgens het ouderwetse principe van bellen naar een locatie, in plaats van bellen naar een persoon. Oftewel, je hebt geen idee wie je aan de lijn krijgt; het zou zomaar een willekeurige bezoeker kunnen zijn. Als er al iemand opneemt... En mocht je iemand treffen met een mening, dan is die mening waarschijnlijk niet representatief voor alle deelnemers, of voor de stichting.

+31 (0)63 227 8700

Er is een tweede telefoon in de lounge ([https://revspace.nl/Telefoon Link naar de relevante wikipagina)]: +31 (0)85 201 7336

Wil je in contact komen met het bestuur, e-mail dan direct naar de betreffende mailinglist (board@revspace.nl).

For the non-dutch speakers among us: If the space is open, your best bet is to call +31 (0)63 227 8700. There is a very good chance that whoever answers will be at least somewhat proficient in English.

= Stichting Revelation Space =

Andere info die je wellicht zocht:

; KvK: 27363894
; Bankrekening zonder spaties: IBAN: NL69ABNA0431158207, BIC: ABNANL2A
; Bankrekening met spaties: IBAN: NL69 ABNA 0431 1582 07, BIC: ABNANL2A

Contact

2017-12-15T01:24:07Z

Thomastheo: /* Telefoon */

__NOTOC__
{|
|valign=top|
= Postadres =
Stichting Revelation Space
Vlietweg 15 B0.04
2266 KA Leidschendam
|valign=top|
= Bezoekadres =
Stichting Revelation Space
Overgoo 1
2266 JZ Leidschendam
[[Bezoeken|Route en parkeren...]]
|}
= Online =

* https://revspace.nl/
* revspace@revspace.nl (mailing list van deelnemers en geïnteresseerden)
* board@revspace.nl (mailing list van het [[Bestuur]])
* [[IRC|#revspace op freenode]]
* [https://twitter.com/revspacenl @revspacenl]
* https://www.facebook.com/revspace

= Telefoon =

Er is een telefoon, maar die werkt volgens het ouderwetse principe van bellen naar een locatie, in plaats van bellen naar een persoon. Oftewel, je hebt geen idee wie je aan de lijn krijgt; het zou zomaar een willekeurige bezoeker kunnen zijn. Als er al iemand opneemt... En mocht je iemand treffen met een mening, dan is die mening waarschijnlijk niet representatief voor alle deelnemers, of voor de stichting.

+31 (0)63 227 8700

Telefoon in de lounge ([https://revspace.nl/Telefoon Link naar de relevante wikipagina)]: +31 (0)85 201 7336

Wil je in contact komen met het bestuur, e-mail dan direct naar de betreffende mailinglist (board@revspace.nl).

For the non-dutch speakers among us: If the space is open, your best bet is to call +31 (0)63 227 8700. There is a very good chance that whoever answers will be at least somewhat proficient in English.

= Stichting Revelation Space =

Andere info die je wellicht zocht:

; KvK: 27363894
; Bankrekening zonder spaties: IBAN: NL69ABNA0431158207, BIC: ABNANL2A
; Bankrekening met spaties: IBAN: NL69 ABNA 0431 1582 07, BIC: ABNANL2A

Telefoon

2017-12-15T01:11:16Z

Thomastheo:

{{Project
|Name=Telefoon
|Picture=Telefoon.jpg
|Omschrijving=085-201-7336
|Status=Completed
|Contact=thomas
}}

'''Deze telefoon is niet bedoeld als vervanger van de mobiele telefoon aan de koelkast.'''

Bereikbaar op '''085-201-7336'''.

Er staat geen beltegoed op, en is dus enkel voor inkomende gesprekken.

Hij staat nu in de lounge.

Het is een PTT model T-65 TDK uit 1979, roodgeverfd.

Hij is aangesloten op een fritzbox, ingesteld als voip gateway, (wifi staat uit).

'''Let op''', dit is een 085-nummer, bij sommige providers valt bellen naar deze nummers buiten de bundel!

Wordt zeer binnenkort vervangen door een 070 nummer, crowdfund incoming...

Contact

2017-12-14T22:40:45Z

Thomastheo: /* Telefoon */

__NOTOC__
{|
|valign=top|
= Postadres =
Stichting Revelation Space
Vlietweg 15 B0.04
2266 KA Leidschendam
|valign=top|
= Bezoekadres =
Stichting Revelation Space
Overgoo 1
2266 JZ Leidschendam
[[Bezoeken|Route en parkeren...]]
|}
= Online =

* https://revspace.nl/
* revspace@revspace.nl (mailing list van deelnemers en geïnteresseerden)
* board@revspace.nl (mailing list van het [[Bestuur]])
* [[IRC|#revspace op freenode]]
* [https://twitter.com/revspacenl @revspacenl]
* https://www.facebook.com/revspace

= Telefoon =

Er is een telefoon, maar die werkt volgens het ouderwetse principe van bellen naar een locatie, in plaats van bellen naar een persoon. Oftewel, je hebt geen idee wie je aan de lijn krijgt; het zou zomaar een willekeurige bezoeker kunnen zijn. Als er al iemand opneemt... En mocht je iemand treffen met een mening, dan is die mening waarschijnlijk niet representatief voor alle deelnemers, of voor de stichting.

+31 (0)63 227 8700

Wil je in contact komen met het bestuur, e-mail dan naar de betreffende mailinglist!

= Stichting Revelation Space =

Andere info die je wellicht zocht:

; KvK: 27363894
; Bankrekening zonder spaties: IBAN: NL69ABNA0431158207, BIC: ABNANL2A
; Bankrekening met spaties: IBAN: NL69 ABNA 0431 1582 07, BIC: ABNANL2A

Contact

2017-12-14T21:25:21Z

Thomastheo: /* Telefoon */

__NOTOC__
{|
|valign=top|
= Postadres =
Stichting Revelation Space
Vlietweg 15 B0.04
2266 KA Leidschendam
|valign=top|
= Bezoekadres =
Stichting Revelation Space
Overgoo 1
2266 JZ Leidschendam
[[Bezoeken|Route en parkeren...]]
|}
= Online =

* https://revspace.nl/
* revspace@revspace.nl (mailing list van deelnemers en geïnteresseerden)
* board@revspace.nl (mailing list van het [[Bestuur]])
* [[IRC|#revspace op freenode]]
* [https://twitter.com/revspacenl @revspacenl]
* https://www.facebook.com/revspace

= Telefoon =

Er is een telefoon, maar die werkt volgens het ouderwetse principe van bellen naar een locatie, in plaats van bellen naar een persoon. Oftewel, je hebt geen idee wie je aan de lijn krijgt; het zou zomaar een willekeurige bezoeker kunnen zijn. Als er al iemand opneemt... En mocht je iemand treffen met een mening, dan is die mening waarschijnlijk niet representatief voor alle deelnemers, of voor de stichting.

+31 (0)63 227 8700

+31 (0)85 201 7336

Wil je in contact komen met het bestuur, e-mail dan naar de betreffende mailinglist!

= Stichting Revelation Space =

Andere info die je wellicht zocht:

; KvK: 27363894
; Bankrekening zonder spaties: IBAN: NL69ABNA0431158207, BIC: ABNANL2A
; Bankrekening met spaties: IBAN: NL69 ABNA 0431 1582 07, BIC: ABNANL2A

Microscope

2017-12-09T21:46:09Z

Thomastheo:

{{Project
|Name=Microscope
|Picture=
|Status=Initializing
|Contact= thomas
|A bio microscope for the space, for looking at more organic bugs and squishy things.
}}

Placeholder,

This page will provide simple how-to and how-not-to for people wanting to use the bio microscope.

More to come.

Microscope

2017-12-09T21:45:39Z

Thomastheo: Created page with " {{Project |Name=Microscope |Picture= |Status=Initializing |Contact= thomas |A bio microscope for the space, for looking at more organic bugs and squishy things..."

Geigercounter

2017-12-02T13:17:22Z

Thomastheo: /* Radon */

{{Project
|Name=Geiger counter
|Picture=GeigerCounter.jpg
|Omschrijving=A geiger counter for the space
|Status= Completed
|Contact=gori
|Contact2=thomas
}}

* [https://www.aliexpress.com/snapshot/6181715232.html?orderId=63338053328673&productId=1790161282 We have this one]
* Documentation : https://drive.google.com/drive/folders/0B9itH-BnWE5sY2JGRkM4MWhSYkE
* [https://revgraph.bewaar.me/dashboard/db/home?refresh=1m&panelId=8&fullscreen&orgId=2 Realtime measurements]

== Software ==
See the geiger_esp sub-directory in this
[https://github.com/revspace/geiger github repo]

The way the ESP8266 version of the software works, is by means of a single pulse counter.
This counter is incremented for every tick coming from the Geiger tube.

Every second we keep track how much the counter has incremented compared to the previous second.
This value is stored in a circular buffer of 60 entries, one for each second inside of a minute.

The 'cpm' value (counts per minute) is then simply the sum of all entries in the circular buffer!
So we can calculate the cpm at any time, without rounding error, it's always the number of measured ticks in the previous 60 seconds.

The software uses the following libraries:
* WiFiClient for general WiFi
* WifiManager to make it easy to setup the WiFi (presents a captive portal to select a network and enter the passphrase)
* PubSubClient to publish measurements to MQTT

Measurements are published to topic 'revspace/sensors/geiger' on mosquitto.space.revspace.nl (also available on revspace.nl)

== Radon ==

In order to try and get our space geiger to display something more interesting than just random variations of natural background, it was put to use measuring the natural decay of radon progeny floating about in the basement of our SectorV location. A piece of filter paper was draped over the opening of our shopvac, and left to suck up airborne particulates in our server room, which of course happens to be the room with the least amount of ventilation. I let it do its thing for about five minutes or so.

Radon daughters are partly alpha emitters, so the space geiger was retrofitted with a different tube capable of detecting them. The stock tube (a chinese M4011) does not sport a mica window, but I have a mullard zp1430 that does. After turning off the vacuum cleaner, I promptly walked the filter back to the hackerspace and plonked the tube on top of it, with the mica window pressed right up against the paper surface.

See the graph below for a nice exponential decay curve of the filtered radon progeny. It surprised me how little time it took to collect enough radioactive particles for a decent curve to reveal itself. To give you an idea, the peak reading represents a particle count that is roughly 25 times above the normal background rate. I've also included a picture showcasing our "highly advanced" setup.

[[File:Radondecay.png|600px]]
[[File:Zp1430.jpg|600px]]

==Pitch in for a geiger counter:==

{| class="wikitable"
|-
! Naam/Nick
! Aantal euro's
! Betalingsmethode
|-
| gori || 5 ||
|-
| Walter || 5 || revbank (Betaald)
|-
| Jos || 5 || revbank (Betaald)
|-
| thomas || 5 || revbank (Betaald)
|-
| Peetz0r || 5 || revbank (Betaald)
|-
| merethan || 5 || revbank (Betaald)
|-
| pepman || 5 || revbank (Betaald)
|-
| bertrik || Wemos D1 mini || natura
|}
DONE! thank you all.

Geigercounter

2017-12-01T23:57:24Z

Thomastheo: /* Radon */

{{Project
|Name=Geiger counter
|Picture=GeigerCounter.jpg
|Omschrijving=A geiger counter for the space
|Status= Completed
|Contact=gori
|Contact2=thomas
}}

* [https://www.aliexpress.com/snapshot/6181715232.html?orderId=63338053328673&productId=1790161282 We have this one]
* Documentation : https://drive.google.com/drive/folders/0B9itH-BnWE5sY2JGRkM4MWhSYkE
* [https://revgraph.bewaar.me/dashboard/db/home?refresh=1m&panelId=8&fullscreen&orgId=2 Realtime measurements]

== Software ==
See the geiger_esp sub-directory in this
[https://github.com/revspace/geiger github repo]

The way the ESP8266 version of the software works, is by means of a single pulse counter.
This counter is incremented for every tick coming from the Geiger tube.

Every second we keep track how much the counter has incremented compared to the previous second.
This value is stored in a circular buffer of 60 entries, one for each second inside of a minute.

The 'cpm' value (counts per minute) is then simply the sum of all entries in the circular buffer!
So we can calculate the cpm at any time, without rounding error, it's always the number of measured ticks in the previous 60 seconds.

The software uses the following libraries:
* WiFiClient for general WiFi
* WifiManager to make it easy to setup the WiFi (presents a captive portal to select a network and enter the passphrase)
* PubSubClient to publish measurements to MQTT

Measurements are published to topic 'revspace/sensors/geiger' on mosquitto.space.revspace.nl (also available on revspace.nl)

== Radon ==

In order to try and get our space geiger to display something more interesting than just random variations of natural background, it was put to use measuring the natural decay of radon progeny floating about in the basement of our SectorV location. A piece of filter paper was draped over the opening of our shopvac, and left to suck up airborne particulates in our server room, which of course happens to be the room with the least amount of ventilation. I let it do its thing for about five minutes or so.

Radon daughters are partly alpha emitters, so the space geiger was retrofitted with a different tube capable of detecting them. The stock tube (a chinese M4011) does not sport a mica window, but I have a mullard zp1430 that does. After turning off the vacuum cleaner, I promptly walked the filter back to the hackerspace and plonked the tube on top of it, with the mica window pressed right up against the paper surface.

See the graph below for a nice exponential decay curve of the filtered radon progeny. It surprised me how little time it took to collect enough radioactive particles for a decent curve to reveal itself. To give you an idea, the peak reading represents a particle count that is roughly 25 times above the normal background rate. I've also included a picture showcasing our highly advanced setup.

[[File:Radondecay.png|600px]]
[[File:Zp1430.jpg|600px]]

==Pitch in for a geiger counter:==

{| class="wikitable"
|-
! Naam/Nick
! Aantal euro's
! Betalingsmethode
|-
| gori || 5 ||
|-
| Walter || 5 || revbank (Betaald)
|-
| Jos || 5 || revbank (Betaald)
|-
| thomas || 5 || revbank (Betaald)
|-
| Peetz0r || 5 || revbank (Betaald)
|-
| merethan || 5 || revbank (Betaald)
|-
| pepman || 5 || revbank (Betaald)
|-
| bertrik || Wemos D1 mini || natura
|}
DONE! thank you all.

Geigercounter

2017-12-01T23:51:35Z

Thomastheo: /* Radon */

{{Project
|Name=Geiger counter
|Picture=GeigerCounter.jpg
|Omschrijving=A geiger counter for the space
|Status= Completed
|Contact=gori
|Contact2=thomas
}}

* [https://www.aliexpress.com/snapshot/6181715232.html?orderId=63338053328673&productId=1790161282 We have this one]
* Documentation : https://drive.google.com/drive/folders/0B9itH-BnWE5sY2JGRkM4MWhSYkE
* [https://revgraph.bewaar.me/dashboard/db/home?refresh=1m&panelId=8&fullscreen&orgId=2 Realtime measurements]

== Software ==
See the geiger_esp sub-directory in this
[https://github.com/revspace/geiger github repo]

The way the ESP8266 version of the software works, is by means of a single pulse counter.
This counter is incremented for every tick coming from the Geiger tube.

Every second we keep track how much the counter has incremented compared to the previous second.
This value is stored in a circular buffer of 60 entries, one for each second inside of a minute.

The 'cpm' value (counts per minute) is then simply the sum of all entries in the circular buffer!
So we can calculate the cpm at any time, without rounding error, it's always the number of measured ticks in the previous 60 seconds.

The software uses the following libraries:
* WiFiClient for general WiFi
* WifiManager to make it easy to setup the WiFi (presents a captive portal to select a network and enter the passphrase)
* PubSubClient to publish measurements to MQTT

Measurements are published to topic 'revspace/sensors/geiger' on mosquitto.space.revspace.nl (also available on revspace.nl)

== Radon ==

In order to try and get our space geiger to display something more interesting than just random variations of natural background, it was put to use measuring the natural decay of radon progeny floating about in the basement of our SectorV location. A piece of filter paper was draped over the opening of our shopvac, and left to suck up airborne particulates in our server room, which of course happens to be the room with the least amount of ventilation. I let it do its thing for about five minutes or so.

Radon daughters are mostly alpha emitters, so the space geiger was retrofitted with a different tube capable of detecting them. The stock tube (a chinese M4011) does not sport a mica window, but I have a mullard zp1430 that does. After turning off the vacuum cleaner, I promptly walked the filter back to the hackerspace and plonked the tube on top of it, with the mica window pressed right up against the paper surface.

See the graph below for a nice exponential decay curve of the filtered radon progeny. It surprised me how little time it took to collect enough radioactive particles for a decent curve to reveal itself. To give you an idea, the peak reading represents a particle count that is roughly 25 times above the normal background rate. I've also included a picture showcasing our highly advanced setup.

[[File:Radondecay.png|600px]]
[[File:Zp1430.jpg|600px]]

==Pitch in for a geiger counter:==

{| class="wikitable"
|-
! Naam/Nick
! Aantal euro's
! Betalingsmethode
|-
| gori || 5 ||
|-
| Walter || 5 || revbank (Betaald)
|-
| Jos || 5 || revbank (Betaald)
|-
| thomas || 5 || revbank (Betaald)
|-
| Peetz0r || 5 || revbank (Betaald)
|-
| merethan || 5 || revbank (Betaald)
|-
| pepman || 5 || revbank (Betaald)
|-
| bertrik || Wemos D1 mini || natura
|}
DONE! thank you all.