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Sunday, July 10, 2011

Slow progress as usual

More electrical issues...two of the phases on MC3 (the trouble child) are now screwy. So we're just going to wipe that side of the board clean and start over.

Actual progress:
I cut out and shaped all the tires. They're cut out of a sheet of 3/8" 70A polyurethane rubber (which was insanely expensive).

I first started with strips, then cut 45 deg angles on the ends.

I tried wrapping a tire around the wheel and holding it with zip-ties.

Unfortunately, I need more coverage to hold the gap closed.
I bought a bunch of hose clamps and massive zip ties to try next. The hose clamps held the gap together well, but another problem came up. The natural position for the urethane is warped when it is curled, which makes the angled-cut edges not want to line up. This means that I can't hold it in place while tightening the hose clamps (which requires two hands). Currently I have no solution to this problem. Maybe a combination of zip ties and hose clamps...I don't know. I can't just glue the edges together, because no fast setting glue is strong enough (it takes a lot of force to hold the edges together). I may end up saying screw it and buying polyurethane casting resin and just casting my own tires.

 Shielding sensor wires:

I bought some sweet 5 conductor shielded wire off of ebay. It's kapton coated, which is a nice feature.

Replaced the green mess of wires.

I can't open the motors anymore without significant effort, so I just spliced wires.

The shield is connected to the sensor ground.
I mostly finished the Wii Nunchuck wireless controller (Shane did the electronics and programming...Thanks Shane!)
It's ugly, I know. I need to figure out a different package. I was too optimistic thinking that I could jam it in the nunchuck.
 Heat sinks:

I soldered a little copper sheet to the 5V regulator (center) on the boards because they get pretty hot. 
The MOSFET package on the left (no heatsink) is going to be removed, along with most of the components on MC3.

And that's about it for now. I'm not planning on gluing tires until we resolve these controller issues- they're what's holding up progress at the moment.

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