21 October - Bluetooth and Blunt Objects

21 October

Yesterday I focused on the telemetry. There's a Bluetooth dongle connected to an embedded computer in the car, which turns the car effectively into a Bluetooth device, visible to other computers. So we fire up a laptop, and tell it to search for Bluetooth devices, and the car pops up on the screen.

The first problem is that Windows wants to know the PIN for this new device. We guess a few at pseudorandom (0000, 1234, etc.), but have no success. We phone John in Perth who wrote the software, and he tells us that it's 7260, which is the model number of the embedded computer board.

Obvious, really. Why didn't we think of that?

(The reason that I am documenting this PIN here is that in two years I will have forgotten it, and will then search my own blog in order to find out what it is.)

We muck around with the boards to general success, and then move the embedded computer to a new location in the car, one that will be less vulnerable to getting hideously crushed whenever we lift the batteries in and out of the car.

After lunch we return, and test the car computer in its new location.

It doesn't work.

Damn.

Windows is showing it as a Bluetooth device, but not as a Bluetooth _network_ device, which is a necessary thing for it all to actually work. I rearrange things, reboot things, spin thrice widdershins, call John in Perth, etc., all to no avail. Some of my testing is done in the front seat of our follow car as Tom does test laps.

We wrap for the day without me solving the problem.

We get partway back to our accomodation before I realise that I've forgotten to turn off the car. "We've forgotten something, go back!" is becoming something of a catch-cry for the team.

Today it was down to the pits again for a little more testing before our next thing. We get there, and discover that we've left the Bluetooth dongle back at the accomodation. "We've forgotten something, go back!" And John does.

The rest of us stay at the pit and clean the sides of the trailer, because our next thing is a visit to St John's school.

John returns with the dongle, and I continue to attempt to narrow down the problem. It starts working again. I don't know why.

We pack the car into the trailer to transport to St. John's school. I am reminded of Hofstader's Law: "Everything takes longer than you expect, even when you take Hofstader's Law into account."

We visit the school. We're visiting this particular school because the principal is married to the principal of Leeming. The visit goes well, and most of the team return to the accomodation for lunch, while I and a few others go take the car back to the pit for more troubleshooting.

The Bluetooth stops working again. I don't know why.

There's a Tesla Roadster in the car park in front of the pits, charging. The charge cable is connected to the car at the point you'd expect the fuel cap to be, and the cable is as thick as the hose on a petrol bowser. The other end of the cable connects to a generator on the back of a truck. The generator is bigger than the car.

The Bluetooth starts working again. I don't know why.

I am becoming gradually more of the opinion that it is not Windows' fault, but is a race condition on the car computer.

Steve Morgan and crew work on the brakes. There are two sounds of Hidden Valley for me: one is the sound of a solar car zooming down the straight. This always causes me to glance up, too late: the solar car is no longer visible through the narrow end of our pit, and the only thing I see is the solar car's follow wehicle. The other sound is Steve Morgan calling, "Press... release... press... release...", as they bleed air out of the brake lines.

We end the day with the Bluetooth still working, and with us (reasonably) ready for tomorrow morning's event: scrutineering.

-- Doug Burbidge http://dougburbidge.com/