Butterfly Logger is a versatile data logger based around the AVR Butterfly. It is a cost effective solution that monitors light, temperature, battery voltage and external sensors. The external sensors can be digital signals, analogue voltages or a frequency.
The first goal was that the device needed to be cheap. With many data loggers, a lot of the expense is in making the device physically robust, as a lot of the times I wanted to record a signal in comfortable workshop conditions this could be eliminated and a "naked" butterfly is acceptable. With the base cost being $19.99 USD for the butterfly and then only the cost of sensors on top, meeting this goal seemed all too easy.
The second goal was to make it easily customisable. I wanted to establish a code base that could be adapted to a variety of projects. So far I have used this software to implement a weather station application and a motion-recording device. In the classic weather station set-up many sensors were recorded at long intervals. In this application it was important for the device to survive unattended for long periods of time (3-4 weeks in the field). Low power consumption and robustness were key. In my second application I wanted to record the output from a triple axis accelerometer. In this situation I wanted to record often but only three channels of data.
More documentation is available at Circuit Cellar
The latest firmware is available at the Sourceforge Project Site here
Any questions about the project should be asked in the forums here.