Retroreflector Bee Tracking Components

Here are the 3d design files, PCB files, links to code, etc.

3d model of bee tracking system
3d model of bee tracking system

Note: these were all made “for my own use”: In particular the 3d models are really awkwardly put together (first time I played with freecad).

The circuit/PCB includes components for:

  • measuring the battery voltages
  • driving the stepper motor (to turn the platform).
  • controlling and triggering the camera/flashes

It is likely most people only want the last of these.

The logic here is that a trigger is sent to the camera. The camera itself has a ‘flash trigger’ it sends back. I then AND this (using a 7408 quad-AND chip) with four flash-selection signals, from the pi. This is because I wanted to control which flashes fired. These then operate 4 transistors which trigger the four flashes.

The best way to approach using the tracking idea, is probably to just build your own solution from scratch, using the general principles:

  • A global-electronic shutter, so that you can adjust the exposure to match the flash
  • Subtracting frames, and then using a bit of logic to try to remove false-positives:
    • Most FPs seem to be ‘blurry’ large blobs (the tags, if the camera is focused are sharp points).

      PCB layout
      PCB layout
    • Consider only considering a true-positive if you have seen a bee in 2-3 images in the same part of the image.
  • Triggering – I use a transistor to do this. I wonder if there are modules that convert from a pi’s GPIO to trigger a flash…

I’m afraid I’ve not looked into raspberry’s new global electronic shutter camera. But this sounds really like a good direction in future: Currently there’s a lot of faff and low reliability around dealing with the cameras I used (the ethernet connection to the camera, the annoying hirose connector, the 12V+ the camera needs etc).


  • pcb/circuit schematic: link. (created with kicad).
  • 3d model of tracking system: link. (created with freecad).
  • The bee_track python module is on github. See README for install notes. link.