Noot / Erwt Notes

Note #12 Saturday 12 November 2011

I’ve assembled the first Erwt and it all fits together rather well:

There are a few issues I’ll need to work out, so I’ll probably do another rev of the board soon.

• The bumper PCB isn’t easily mountable in the way I’d hoped (on the front two bolts). I may need to rethink the design.
• The wheels are very close to the PCBs so I’ll move the motors out a little.
• There’s not enough space around the bolts for washers (which are needed to raise the bolt heads up enough to work as casters).
• The buzzer is too quiet with the double RC filter. I took one filter out and it’s a bit better, but is less crisp.
• The P2N2222’s I ordered have a different pinout from standard PN2222A’s (emitter-collector reversed).

All relatively minor issues in the end, and all the IO (except the bumper) seems to work quite well. I have tested light following, line following and basic sound generation successfully. I’ve also written some basic libraries for the Arduino UI to support the various functionality. I’m now working on getting a kit ready for a friend to test:

The next steps are to fix up the various issues above, finalise the Arduino libraries, and finish the assembly instructions.