A Three Hour Tour

Maybe it’s just me, but I often wish I knew the temperature outside, and maybe the temperature inside too.  Not because it is really significant or anything, but just out of curiosity.  Then I thought, why not log the temperature so I can graph it over a long period of time and see weather trends?

So I think for a moment, and think… how can I read the temperature?  Immediately I think of the Lego Mindstorms RCX and its temperature sensor.  So I rig up a program for the RCX that logs temperature values and a Linux program that periodically uploads the datalog, and I have success!

But not quite.

First, the RCX is rather finicky, not to mention expensive. I need to have it plugged in via a wall plug, which means I need to take out the batteries, which means that if the cord is jostled or the power fails, I need to re-download the firmware and the program.  It also communicates via IR, so if the sun hits it in the right direction or it loses line-of-sight with the transmitter, the data is lost.  Annoying.  So I set out to do one better.

My current set-up is available from my room in Saxon, dutifully logging away every fifteen seconds for as long as the computer is running.

So I’m blogging on a time crunch (never a good idea!) so here’s a teaser for next time:  I’m using the One-Wire Bus to communicate with a transistor-shaped device over phone wires.  A USB->Serial port interface, on a breadboard, provides the PC to one-wire bridge, and a custom program grabs the data and logs it.  More to come!