I started soldering the motor controller board for R8 today, and realized that I'm totally spoiled by designing and ordering boards from OSHPark. There are 2 other robotic projects I consider working on, that would also need a motor control at some point - the magical number 3 (boards) of ordering at OSHPark. There is the already infamous BB-8 / R0-T8, the rolling bot from the new star wars installment "Episode VII" for that I've ordered a 20cm plastic ball, matching the size of a 12cm dish. I can't believe that already know its both names. The third robot in need of a controller would be Emiglio, a not so little robot I scored on eBay. One gearbox is broken and pretty much all the electronics where not reusable.
There are probably some open source robotic platforms I could try out, that work with arduinos, but I always end up doing my own stuff. I should at least push all my code, pcbs and 3D parts online. The shield I designed has the GVS feature that should allow for some easy servo installation and should be plug and play to the serial bluetooth dongle I bought at eBay. This makes it possible for some Android apps to control it.
I hope I manage to power R8 by one of four 2750mAh LiPo cells I harvested from a broken macbook with a boost converter to 5V, but I have to measure the current of the motors and the arduino + bluetooth module to figure out if the boost converter will be able to give enough power. If not, I would have to use a second one in series and separate the power supplies for the controller vs. the motors.
Is anyone of you using the rectifying diodes with the L293D? I've never seen them in a diagram/schematics before, so I was surprised checking the datasheet. Anyway, I've ordered those purple beauties. I know, I said I wouldn't order boards after midnight, but I've checked all the connections this time. A prototype is something I still have to solder though, since I want to see some progress with R8.