Tuesday, August 20, 2013

empiriKit sensor units, 3D printed cases & more

Here at empiriKit we are working on the preparations for our Danish high school pilot trials starting in the autumn. Freescale kindly sponsored us with a set of FRDM-KL25Z boards that we are using as sensor input units for some of the science experiments.

The Freescale FRDM-KL25Z is a great little board with many built-in features:
  • 3D accelerometer
  • RGB light emitting diode
  • touch sensor
  • can be battery powered from a CR2032 (3V coin cell battery)
To make it easy to use for classroom experiments, we designed a plastic case using Autodesk Inventor Fusion, a 3D design program. After a couple of quick iterations we created a box that is working well.

This picture shows the completed plastic case, including the FRDM-KL25Z board:

The students need to be able to run experiments disconnected from the Raspberry Pi that we use as a host computer. In order to make that possible we mounted a coin cell battery holder on the bottom of the FRDM-KL25Z board (it is already prepared for that), a protection diode and a power switch.

We designed it all to be as compact as possible, at the same time keeping it versatile and easy to use. On the top cover of the case we made a light guide to allow use of the RGB light emitting diode in the experiments. We also left the touch area accessible in the design.

Putting it all together inside the plastic case looks like this:

And with the back plate screwed on it looks like this (the touch sensor area is the accessible part of the FRDM-KL25Z board):

Right now we are writing software and developing the science experiments for the school pilot. More on the embedded software as well as the Raspberry Pi software later.