w e e k T e n

i n p u t D e v i c e

My goals for this week were...to fix my week8 servo board and add a button to it...and create a new accelerometer input board that had leads for output.

So first, i added a button to the board i drew for week8. After milling the new board, i realized i had put a 8hz crystal instead of a 20hz crystal on the old board, which was probably causing all the PWM problems i had last during that week.

Our fablab was momentarily out of the 20hz crystal i had used, but had another resonator that required different pads. So, i decided to scavenge a piece off of an old board.

After adjusting the PWM to be specific to the servo motor, the board was working and behaving in a way that was predictable. Next onto the accelerometer...

The accelerometer board was based off of Neil's example. It switched out the ATTiny 45 for the ATTiny 44 so i could add leads to some LED output. Joe helped me understand how to switch from the 45 to the 44 and Olga showed me how to make new Eagle parts so i could have a breakout board with the LEDs.

The milling was challenging because of how small the accelerometer pads were. Also i made a beginners mistake of not using enough double stick tape. I trimmed down the traces and indicated a slightly smaller tool diameter on mods to get the traces to come out. Even after that, it had to be cleaned up with and blade a bit. After a lot of troubleshooting I finally got power through the board and into the programmer. I used a 0 resistor to bridge an incorrect trace.

The board was still not able to be recognized when I tried to program it. I triple checked all the traces around the ATTiny 44 and the ISP with no luck. I tried to simply, so I made Neils example board to see if the problem was more upstream on my computer. After not much trouble i was able to get the board communicating and sending information which the python code displayed.

The reflow soldering also went smoother the second time around. The confirmed the problem was in my new board and pointed out i had used the wrong regulator. I switched out the part but still no communication. After triple checking the traces around the ATTiny 44 and the ISP i couldn't figure out what was wrong. I think my next steps are going to be replacing the 44 (incase i burned it out with all the prior power and regulator erros) and if that doesn't work redraw the board in Eagle.