Older blog entries for gear21 (starting at number 1)

This week I soldered up the "secondary board" to my OOPic2 so I can attach the 40pin IDE connector to it without soldering my OOPic board. From the secondary board, I have 8 outputs (enable,fwd,rev, and PWM-speed for left and right) and 7 inputs (5 contact switches, 1 IR module, and 1 A2D for battery monitoring). BTW, solder flux RULES!

Since the switches are bolted to the outer shell of the bot, the connections are made to an IDC header, that I can connect the switches to. That way I can remove the shell without having permanent wires attached. Using the internal pullup resistors on the OOPIC is going to make the switch circuits really simple and clean.

I got a couple emails about the wheels and gear motors. I bought the motors from www.sciplus.com about 8 months ago. They were from one of the battery operated kiddy cars. The output shaft was unique in that it was 2.25" in diameter and was divided into 10 sections. I was originally going to just replace the shaft completly, but as luck would have it, by breaking off every other section, it fit exactly into my lawn mower wheels. (shell1.jpg shows the wheel). This was an astounding bit of luck that it matched size, radius, and depth! After that, I bought two more motors as spares!

2 Apr 2002 (updated 2 Apr 2002 at 22:26 UTC) »

Finally posted some pictures of my as yet un-named robot. There isn't an index yet, but they can be seen at: http://www.gear21.co m/scook/bot/

The skeleton is built from aluminum pieces scrounged from around work (which is why it is almost exactly the same size as a 12u rack-mount network switch :).

I used "off the shelf" DC motor controllers after many variations of H-Bridges I built just didn't have the flexibility I wanted... For the new controllers, I made a "universal interface" using cat5 ethernet cable and rj45 connectors, so I can swap out drive methods (from connected switches, remote control, to onboard microcontrollers).

Originally I was using a parallel port on a laptop to send signals to the motor controllers, but the laptop was just too big, so I got an OOPic a few weeks ago, and have started using it as the brains...

This week, I'm making an interface to the OOPic so I can connect 5 contact switches and 1 IR range module for external sensory duty...

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