We decided the best way to launch something was to put it in a rocket…

Take an mbed Microcontroller, add an 18g accelerometer and attach a PP3. Wrap in a polybag and tada, a rocket datalogger!

The idea is to put this in the body of the rocket. Model rockets have a motor which after burning through pauses for a while before firing on the other side. This is designed to blow off the nose cone to release the parachute. As this is where our logger is going to be, that also means the logger will get blown out! The green wire coming out the top is our solution to tie it to the rocket nose cone so it doesn’t go to far.

We had been hoping for good weather. It was sunny but windy. Actually, very windy, to the point of being hard to stand still easily. So that unfortunately meant it wasn’t suitable for firing rockets.

But we did anyway…

After running to collect the rocket before it blew away, we opened it up, plugged it in to the laptop and fired up excel. The data looked good – first time too!

Here’s the resulting data from the flight, annotated with what we worked out was going on…

A rocket datalogger built in an hour, and fired the same afternoon giving us results first time. I’m happy with that for a launch!