Project Log : Arduino Enclosure

For more background information and an explanation of this project see also: Project Arduino Case

( 26 January 2009 )

• Have been discussing the project with various people around Europe.

• Discussed possible prototype possibilities. Installed Art of Illusion. Can't seem to apply materials/textures to objects, not sure why.

• Created an initial mock-up of a one button, three LED enclosure design in AOI. (Can't seem to apply textures though.) (source)

• Did tear down and took photos of give-away "tamagotchi-style" hand held game device.

• Built fractionally more recent version of KiCad from source.

( 27 January 2009 )

• Was shown how to make textures work.

• Installed CSG operations AOI plugin.

• Created initial coin cell battery holder design.

• Created rough schematic and very rough layout of a board. (kicad source files) Screenshot:

( 28 January 2009 )

• Made a mock up of possible coin cell battery connector construction inspired by earlier toy tear-down. Turned into a torch:

• In the above images the top cardboard piece represents a single-sided PCB and the bottom pieces represent the printed enclosure base. The foil would likely be a small strip of metal—it continues under the battery.

• Put together a breadboard circuit and powered it from the coin cell successfully. Note the awesome cardboard + wires ICSP header:

( 29 January 2009 )

• Added images/source files for rough layout above.

• Revised schematic and board layout. (kicad source files) It now fits in ~ 52mm x 33mm. Screenshot:

• Also used Circuit People Gerber Viewer to produce an board image--but have yet to print it actual size.

• Added LEDs to breadboarded circuit. Experiments with PWM indicate I need to think more about clock speed impact on the Arduino core. Still, three flashing LEDs is enough to amuse some people. Like me. :-)

• Would like to consider moving the ICSP header away from the LEDs so the LEDs can be separated more but will see what progress I can make with making a board before I try that I think.

( 30 January 2009 )

• A very productive night/morning thanks to some pointers from Metalab inhabitants. :-)

• Too tired to upload everything now but... I UV exposed & chemically etched a set of boards and partially assembled one—everything except the microcontroller. The parts I tested so far seem to be working (including insanely bright LEDs). Here is an image of the boards—partially cut—along with the transparency used for the exposure:

• And here is the partially assembled board—probably no prizes for SMD soldering but it is a first effort :-) :

( 31 January 2009 )

• Success! With some guidance from a local SMD soldering guru I managed to attach the ATmega168 SMD microcontroller to the board successfully. Also added some resistors to the LED lines as I had misunderstood some advice. Also made another battery holder out of cardboard. Very poor quality video (ogg).

• In full light:

• Full view of top of PCB sans sophisticated closure mechanism:

• View of bottom of PCB and top of battery holder:

• View of battery holder from bottom:

• Programmed the device from the Arduino IDE with a direct programming configuration for the usbtiny programmer.

( 1 February 2009 )

• Uploaded LED chaser test: test_enclosure_pcb_board.pde

• Uploaded LED chaser with switch-activated speed change test: test_switch_3.pde

• Future reference:

    * Switch input: Digital Pin 14 / Analog Pin 0 (requires internal pull up resistor to be enabled)

    * Two outside red LEDs: Digital Pin 6 and Digital Pin 10

    * Middle Green PWM/sensing capable LED: Digital Pin 7 (High) and Digital Pin 9 (High or Low)
      -- (should be opposite way around, LED backwards on board)

• Tested LED as sensor with code from playground and it worked: test_board_sensor.pde

• Wrote a reaction tester game and tested it on two Metalab inhabitants, guess that makes this a handheld gaming device now. :-) Reaction tester source code: reaction_tester.pde

• Finished up my PCB etching notes on the Metalab wiki.

• Most recent (etched) revision: schematic and board layout (kicad source files)

• I would be inclined to: 1) increase the width of signal tracks, 2) have longer pads on non-connected pins to easy hand-soldering.

• Note: The above board need(s) following fixes: reverse direction of the LEDs, add resistors for all LEDs (68 Ohm). Suggested addition: bring out serial connection to pads

( 2 February 2009 )

• Modified the board design to be about half the size (now ~50mm x ~25mm), increased signal track size, added resistors, brought out serial (untested) and made other fixes.

• In spite of a very poor print around the microcontroller I managed to get the board etched and assembled. Conveniently there was a scrap of board just large enough for a 2-up etch. It took a very long time though for reasons I do not know. I also needed to use a scalpel to make the board functional. A poor soldering job by moi meant it took a while to get it working and I wasn't able to test the headerless programming successfully. I did eventually remove the header and tested with some machined pins and was able to reflash the device a couple of times but it was fiddly.

• A side by side size comparison of the first and second generations (you'll note they would both benefit from a proper enclosure!):

• Generation two glowing at the start of the reaction tester game:

• Full PCB and battery holder/back:

• Rear of PCB featuring battery contacts:

• Still need to upload source files etc. I think the middle LED is somehow still backwards or at least not operating as I expect.

( 18 February 2009 )

• Finally uploaded schematic pdf, (poor) board layout pdf and kicad source files for the generation two board.