Difference between revisions of "Progromino"

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m (Adjusted picture size)
(Updated TODO list)
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1. After reviewing the CR2032 spec, looks like it's not sufficient to drive 60 ma - the maximum current required with 3 LEDs on.  Fallback is to use 3xAAA batteries, but that's bigger than the device itself!  There must be a better solution for powering it.
 
1. After reviewing the CR2032 spec, looks like it's not sufficient to drive 60 ma - the maximum current required with 3 LEDs on.  Fallback is to use 3xAAA batteries, but that's bigger than the device itself!  There must be a better solution for powering it.
  
2. The LEDs used as sensors get cross-illuminated by the adjoining LEDs.  Investigate using different wavelength LEDs, shrouds, or some other means to isolate them.
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2. For the initial version, was not able to incorporate the switch (too expensive for switch and PCB space). Need to come up with a suitable H/W and S/W solution.  Springy wire?  Using ATTiny44A provided a complete SPI interface and one extra unused pin!
  
3. For the initial version, was not able to incorporate the switch (too expensive for switch and PCB space). Need to come up with a suitable H/W and S/W solutionSpringy wire?  Using ATTiny44A provided a complete SPI interface and one extra unused pin!
+
3. Update schematicThe LEDs used for sensing the light input are upside down!

Revision as of 00:39, 30 April 2011

We don't need no stinking 555 timers! We have an AVR in the same form-factor!

The goal of this project is to design an electronic domino using a small AVR chip and minimal components, but at the same time provide a huge amount of flexibility and capability. Here's the 555 version:

http://relwin.hackhut.com/2011/03/01/555-timer-contest-entry/

And here's the current design:

alt text

TODO

1. After reviewing the CR2032 spec, looks like it's not sufficient to drive 60 ma - the maximum current required with 3 LEDs on. Fallback is to use 3xAAA batteries, but that's bigger than the device itself! There must be a better solution for powering it.

2. For the initial version, was not able to incorporate the switch (too expensive for switch and PCB space). Need to come up with a suitable H/W and S/W solution. Springy wire? Using ATTiny44A provided a complete SPI interface and one extra unused pin!

3. Update schematic. The LEDs used for sensing the light input are upside down!