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It's been a while since I wrote anything at LMR, so an update is due: I've been messing about with an Arduino Duemilanove that I was given for Christmas 2008. I've done all the usual things with LEDs, servos, LCDs and the like.  Also spent way too much time at the Arduino forums!

Now that I have the rotary encoders working properly, it's time to think about the motor control circuit.  I have an Atmel AVR ATmega32 with three PWM outputs, of which I'll use two for motor control.  I'm planning a differential drive robot, that is, one with two drive motors, one for the left side and one for the right side.  I'll need forward and reverse directional control of both motors, as well as speed control via PWM. I have a couple of L298 H-bridge chips, so they'll do nicely.

This is a photo of the encoder disk that I'm working on for the Hitari Tumbler robot chassis modification.

I'm looking at a Hitari Tumbler radio-controlled car chassis.  It has four wheel drive, with front and rear wheels on each side geared together, and to the motor.  There are, of course, two motors, for left and right side drives.  It's old, and missing the bodywork, battery and radio transmitter -- but we won't be needing any radio!

Yesterday, I made my first PCB since about 1978!  I used the toner transfer method, and it worked really well.  It's a little break-out board for an Atmel AVR, the ATmega8.  I've also allowed space on the board for a couple of extra chips (up to 18 pins) and four TO-220 driver transistors, for things like stepper motors.  Today, I'm drilling the holes in the board (1mm) and I expect I'll solder in the parts this evening.

Today, I received The Great Internet Migratory Box Of Electronics Junk!  It's called "Woking1" and it's the first such box to wend its way around the UK. The idea is a bit like a mobile geocache; you take a few useful parts out, put a few useful parts in, and then send it on to someone else.  There's a Wiki all about it here: http://tgimboej.org/ and my photo set on Flickr here: http://www.flickr.com/photos/anachrocomputer/sets/72157606706573085/