Wednesday, August 23, 2006

CompuRally - the early days

As I have mentioned before, CompuRally started out on a TI-55 calculator. It later evolved to an HP 41c and later to the 41CX with the time chip.

As Jeff and I learned more about industrial controls from automating our process at Westvaco, we decided to upgrade to computer data acquisition.

We found a card that would count pulses for an IBM clone computer. I built an encoder in the brake rotor of my Datsun 510 by drilling holes and using a proximity sensor to generate pulses. The card in the computer did the counting. The Compurally software written in BASIC did the math and displayed the result on a 7 inch monitor mounted where the glove box should have been in my 510.

The desktop computer ran off an inverter and was mounted to the cargo area floor of my 510 wagon. We had long cables to connect the keyboard and monitor.

As good engineers we tried to think of every thing that might go wrong with the set up and plan for the contingencies.

We tested everything we could think of and when the system seemed bulletproof, we headed to Atlanta to give it a go against Ken and Robert's Zeron computer.

In the back of my mind I was still thinking that somethiong would go wrong with our hacked together system. But we had tested everything we could think of. What could possible go wrong?

While running the odometer calibration leg, we drove under so low hanging power transmission wires. Just as we drove under the wires, the computer rebooted, loosing all our calibration data.

At first we did not associate the wires with the reboot, but after the computer rebooted for the third time in the exact same spot we decided it must be something in the wires. Who would have thought that the power would set up enough resonance to reboot our computer in the car?

After that rally we added shielding to the long cables and never had another reboot. The later version for our laptop computer eliminated the trouble altogether.

Sometimes I wish I was not so good at manifesting problems to correct. To read more about the dark side of manifesting your fears click here.



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