I have already sent off a request for an invitation to the beta version and am watching my inbox with excitement. I can’t wait to use an arduino to start logging some data to share online. I would love to track the sun light in my garden or the energy usage in my house or use Pachube as part of a home automation system. Perhaps I will be able to monitor how much time I spend making music versus downsurfing on the interweb!

There is already a convenient way to follow peoples Pachube feeds on your iPhone but it might also be interesting to explore the API and create a handy Pachube iPhone app of my own.

Trimet

The second bot that I built was a ‘Solar Roller’. It uses the same 1381-based solarengine as the Trimet but this time with a single 0.33 Farad gold capacitor. The body and wheels were salvaged from a VCR and a cassette walkman.

Solar Roller

The 1381-based solarengine works like this: The solar cell charges the capacitor. As the capacitor gains more charge, the voltage across it increases. Eventually the voltage reaches the critical point for the 1381 and it supplies current to the base of the 3904 NPN transistor. This turns the 3904 on so that current is drawn through the motor and from the base of the 3906 PNP transistor. This current turns the motor and the 3906 on, effectively removing the 1381 from the circuit. The motor continues to run as the capacitor finishes discharging.

Solarengine schematic from www.solarbotics.net

To see some great solar bots go here.