For the 12 Hours in the life of a Fox project, we needed a collar with the following specs:
- lightweight enough for a fox
- recording continuously for as long as possible
- that could detach itself after 12 hours or a low battery life
- that could be found easily in the forest
We decided to go for a yellow 3D-printed collar. An Arduino board controlled the timing and the battery level, the opening of the hook and the sending of coordinates. The recording was made thanks to another device with its own power source to maximize the recording time.
The hook has first been designed:
An aluminium version has been machined first:
The hard part was to find a micro linear servo (below in the 3D-printed versio of the hook).
We eventually decided to include the hook directly in the collar design, we only kept the linear servo controlled by the Arduino board.
The coordinates were sent thanks to a GPS/GSM board which used text messages to send the coordinates every minute or so. We could then trace a map of the fox wander.
The collar used AA battery for the Arduino, GPS/GSM board and the servo. The recorder had its own power unit.