31 January, 2007

by Adam Hyde

Its been a busy few days. We fly out to the boat in 2 days and so its a mad rush to get everything done. Tom, Amanda, and First Born have been very busy outside with the AWS unit, setting it up with the wind turbines and solar panels. It looks fantastic and they ahve done an excellent job.

Its been pretty cold these last days, and they have been outside most the time coming back looking frozen. Today the wind turbine was finally working, and tomorrow we install all the AWS and communications equipment.

In the meantime I have been inside working on the networking systems (writing scripts etc). Its been warmer work than my colleagues but possibly a little bit more boring! ;)

Still, today was rewarding. I was looking for a way to restart the computer that will be in the AWS. If the batteries fail in the unit (if there is a storm during winter or other reason), then we need a way to power the computer on once the batteries have recharged. There are a number of ways this could be possible with some machines (bios settings for example) but this computer supports none of them. The computer has a on/off button which if depressed momentarily the computer starts up. So, we needed a circuit to solve this. After wedging off a plastic panel it appears that shorting the button momentarily would also start the computer.

So, we needed a circuit that would do this automagically. I wondered if a relay would do this. A relay will close a circuit when power is applied, but it couldnt do this on its own, so I mailed some friends. We had excellent brainstorming sessions, and Mr Snow and Matthew Biederman helped shape the idea of what was necessary. But we had no circuit. So I visited Pierre (one of the scientists here) and naively asked him if a series of relays might do the trick. Before I knew it Pierre had sketched out a circuit on some paper and helped me source the parts. I built it but it didnt work...so, Pierre then troublshooted the circuit, it took a good 6 hours or so. I could mumble some agreements, and nod a few times, while Pierre whizzed through the possible causes for many problems we were having with the circuit. Finally, we had a circuit that works. It might look a little crzy, but it does the job.

So now, if the batteries fall below 6 volts, the computer is more than likely to be turned off. Then when the power rises, at 10 volts the circuit triggers some relays, one of which short circuits the on button for half a second of so and the laptop starts. Pierre is now drawing the circuit diagram and tomorrow we will publish it if anyone wants to use such a thing.

Anyways, off to bed now, a big day tomorrow.