LaserCutterUsageCounter - Revision history

Bertrik Sikken at 09:55, 14 February 2016

2016-02-14T09:55:20Z

← Older revision		Revision as of 09:55, 14 February 2016
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	== Status ==		== Status ==
	I haven't worked on this project for some time, I still think it's a good idea and there is some initial code. However I consider it low-priority for now.		I haven't worked on this project for some time, I still think it's a good idea and there is some initial code. However I consider it low-priority for now.

			[[Sebastius]] actually built something like this already, making this thing obsolete.

	== Context ==		== Context ==

2015-07-30T15:46:49Z

← Older revision		Revision as of 15:46, 30 July 2015
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	{{Project		{{Project
	\|Name=LaserCutterCounter		\|Name=LaserCutterCounter
	\|Status=~~In progress~~		\|Status=Stalled
	\|Contact=bertrik		\|Contact=bertrik
	}}		}}


			== Status ==
			I haven't worked on this project for some time, I still think it's a good idea and there is some initial code. However I consider it low-priority for now.

	== Context ==		== Context ==

2014-12-30T12:25:22Z

Implementation

← Older revision		Revision as of 12:25, 30 December 2014
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	Block diagram:		Block diagram:

	[[File:LaserCutterUsageCounter.svg]]		[[File:LaserCutterUsageCounter.svg]]

			Solid blocks: software
			Dashed blocks: hardware

	Software development is on [https://github.com/bertrik/LaserCutterUsageCounter github].		Software development is on [https://github.com/bertrik/LaserCutterUsageCounter github].

2014-12-29T15:14:20Z

Wear-leveling algorithm

← Older revision		Revision as of 15:14, 29 December 2014
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	The checksum makes it likely that a half-written slot can be detected (e.g. when a power-down/crash occurred during writing).		The checksum makes it likely that a half-written slot can be detected (e.g. when a power-down/crash occurred during writing).
	An invalid slot can be skipped this way, and we automatically fall back the slot before it.		An invalid slot can be skipped this way, and we automatically fall back the slot before it.
	When writing, we simply write to the next slot than we one we read from, using a higher sequence number.		When writing, we simply write to the next slot than the one we read from, using a higher sequence number.

	Assuming a write frequency of once per minute, it takes about 64 * 100,000 writes before the EEPROM reaches its official limit, this amounts to about 100,000 hours.		Assuming a write frequency of once per minute, it takes about 64 * 100,000 writes before the EEPROM reaches its official limit, this amounts to about 100,000 hours.

2014-12-29T11:52:48Z

Implementation

← Older revision		Revision as of 11:52, 29 December 2014
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	== Implementation ==		== Implementation ==

			Block diagram:
			[[File:LaserCutterUsageCounter.svg]]

	Software development is on [https://github.com/bertrik/LaserCutterUsageCounter github].		Software development is on [https://github.com/bertrik/LaserCutterUsageCounter github].

2014-12-27T21:58:42Z

← Older revision		Revision as of 21:58, 27 December 2014
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	{{Project		{{Project
	\|Name=LaserCutterCounter		\|Name=LaserCutterCounter
	\|Status=~~Initializing~~		\|Status=In progress
	\|Contact=bertrik		\|Contact=bertrik
	}}		}}
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	If using a 16-bit CRC for the checksum, the best choice to protect our 112 bytes of data is the one with polynomial 0x9eb2, according to [http://users.ece.cmu.edu/~koopman/crc/ this great page on CRCs]. It can reliably detect up to 6 flipped bits.		If using a 16-bit CRC for the checksum, the best choice to protect our 112 bytes of data is the one with polynomial 0x9eb2, according to [http://users.ece.cmu.edu/~koopman/crc/ this great page on CRCs]. It can reliably detect up to 6 flipped bits.

			== Implementation ==

			Software development is on [https://github.com/bertrik/LaserCutterUsageCounter github].

2014-11-13T16:52:00Z

User interface

← Older revision		Revision as of 16:52, 13 November 2014
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	=== User interface ===		=== User interface ===
	~~Probably a standard 2-line 16 character~~ display ~~can be used.~~		To display the usage counters, a Nokia 5110 display (84x48 pixels, or 6 lines of 14 characters) is used.
	~~We could use one line for~~ the ~~current session~~ counters ~~and the other line for lifetime total counters.~~
	~~Alternatively, to display all data~~, a Nokia 5110 display (84x48 pixels, or 6 lines of 14 characters) ~~can be~~ used.

	Example: use a nokia 5110 display and alternate between these screens:		Example: use a nokia 5110 display and alternate between these screens:

2014-11-13T16:50:50Z

Electrical front-end

← Older revision		Revision as of 16:50, 13 November 2014
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	The LAOS-board in our laser cutter probably runs at a PWM frequency of 20 kHz (the default).		The LAOS-board in our laser cutter probably runs at a PWM frequency of 20 kHz (the default).

	Proposed low-pass filter: 1 ms RC-time (this is 20 ~~time~~ the PWM period)		Proposed low-pass filter: 1 ms RC-time (this is 20 times the PWM period)
	Proposed sample rate: every 100 ms / 10 Hz		Proposed sample rate: every 100 ms / 10 Hz

2014-11-07T14:05:32Z

User interface: update examples

2014-11-07T10:27:10Z

Add display examples

@@ Line 59: / Line 59: @@
 We could use one line for the current session counters and the other line for lifetime total counters.
 Alternatively, to display all data, a Nokia 5110 display (84x48 pixels, or 6 lines of 14 characters) can be used.
 The button is a push button.