Post #8: Fumble Recovery

Fumble Recovery

Tonight was a good night, I recovered my own fumble.  In the last post I mentioned how I created a circuit that was one giant short circuit, remember? After searching for a plan B, it occurred to me that if I had just a tiny bit of luck (actually, 50/50) and I have access to the traces on my little perfect board, I could cut them away and recover my mistake! Yay! As luck would have it, I can cut away the traces and get back to my perfect mounting scheme! (for all you experienced robot makers, this is probably old hat for you...).  I took a hack saw blade and ran it across the back in between each of the pins. Doesn't look nice, but you won't see it anyway.  It worked! An ohmmeter proves that no pin has continuity to any other pin it isn't supposed to! Plan A back on track.

Compass, top dead center.

Compass with Bluetooth

In fact, I finished soldering on the pins to my bluetooth and compass circuits, mounted this pcb to the top shelf and installed it all up just so I can 1) see if my compass is top dead center and 2) mark mounting locations for the rest of the boards. As you can see, the compass is top dead center (not sure if you can see the pencil lines that crisscross over the center of the panel). Next to the compass is the Bluetooth, there was enough room on that board for both. Mounting it off center gives me the space I needed to center the compass.

I've marked my holes for the Arduino and a power bus, now would be a good time to assemble the PIXY and see what it is going to look like so I can figure out how to mount it. The little black dots you see on the left of the mounted circuit mark the holes for the Arduino (I have to take my creation off the board before I drill new holes). That leaves the space over on the right (front) of the panel for the PIXY. The base on this thing is kind of big, I'm going to think about it for a bit, good ideas always come to me overnight.

the Assembled PIXY!

So, lets get to know our little PIXY. Here is a pic of the PIXY next to the platform. It is pretty large compared to the space I have to mount it. There are 4 holes on the bottom plate that look like I'll be able to use for mounting, but the challenge, how to re-attach the servo plate.... I'll think on this a while.

I followed all the instructions on the cmucam.org wiki page, sometimes twice.... can be confusing at times, I assembled a couple of things backwards, twice :).  Anyway, once it is all assembled and the wires all tucked away nicely, I went ahead and ran the pan/tilt demo. I'm glad I did, the pc kept complaining that it was using too much power, so... that means I'll really want to think about powering this little guy. Anyway, check out the pan/tilt demo, pretty much ran out of the box. I picked the yellow handles on my electricians tool to track, did pretty well!

Not bad for straight out of the box. There are tuning parameters for the proportional and derivative gains on the tilt and pan servos, but I didn't mess with them. The Arduino will be controlling the servos ultimately (telling the PIXY where to move the servos) so tuning the PID controllers in the Arduino will be the place where that gets done.

Anyway, good night.  Time for sleep :)