From the hardware point of view, an ethoscope is rapsberry pi powered machine that tracks flies using a raspberry pi camera. In principle, all you need is a way to keep the camera at the focal distance from the flies and given that tracking needs to happen during night too so you will also need a way to keep infrared illumination. We normally print ethoscopes using a filament extruder 3D printer. We have three Ultimaker 2+ in the lab and we are happy with those. If you are not on a tight budget you may want to consider an Ultimaker 3 (amazon ~£7k) or you may want to go with an inexpensive model like the Creality 3D (amazon £250). I have no experience with cheaper models but my understanding is that the technology has improved a lot and I am pretty confident everything you will want to print can ben printed on a Creality printer.

A typical 3D printed ethoscope in all its beauty

A typical 3D printed ethoscope in all its beauty

Files to print and other resources

The node platform provides the most up-to-date list of files to be printed and I recommend you start from there. Click the "Resources" page and you will see a list like the one below:

In this manual, I will provide instructions on how to build an ethoscope using the files versioned 1.7 and while I am confidents update will roll out quickly enough, I do not expect them to change drammaticaly.

Name Vendor (link) Cat No Price per ethoscope (£)
Raspberry Pi 3 B+ 2842228 33 60
Raspberry Pi Camera PiNOir V2 3677846 14 29
32GB Class 10 MicroSDHC micro sdhc 3410189 7 7
12V Infrared LED strip HK-8MM-F5050-850-15-NW-IR-12 1
Female 2x40 IDC socket (fits the GPIO) 625-7303 2.5
Female 2x3 IDC socket 832-3613 1
Male 2x3 IDC socket 832-3496 1
2 core DC cable 714-0313 0.01
Tactile Switch 135-9601 0.05
60W USB Power supply
Sticky tack 0.001
PI Heatsinks 1
3mm opal acrylic sheet 1 1
Heatshrink tubing (1.6mm) 1008428
Heatshrinktubing (12mm) 4967239
Mirror reflective A4 paper
6-way Ribbon cable RS Components 693-7699 0.15
Total ~£65

The PI case

You will not need any glue or screws to assemble the ethoscope because most parts will snap together. You will, however, need to make some soldiering on the wires. Some sticky tack is also useful to secure components and to darkened LEDs.

  1. Place the heat sinks on the PI. You should cover the two chips facing up (as in the picture below), but not the one facing down. If absolute darkness is an important aspect of your experiments, you may also want to place a little fragment of sticky tack to cover the two LEDs (one red and one green) which are located near the USB power supply socket.

  1. Prepare the piNoir Camera inserting the ribbon cable making sure it is inserted in the right orientation (text up) - double-check that you bought the right camera, i.e. the piNoir that does not have an embedded infrared filter and has a black PCB.

  1. Insert the camera into the camera slot, fitting the four pins inside the four appropriate holes. Make sure the camera is well positioned then secure it down by pushing the camera cover lid. The lid will click into place making sure the camera will not move during experiments

  2. Place the rasbperry PI on top of the camera, positioned on its four pillars and secure the other end of the ribbon cable into the PI. It's easier to insert the PI into the case without the SD card in. You can then insert the SD card once the PI is fastened inside. Use some sticky tack on the PI pillars to secure the base in place, then close the lid of the case.

<aside> 💡 The four external round holes around the camera found on the case are made to accommodate LEGO Technics pins. Their distance is also LEGO Technics compatible. This allows you to create LEGO plugins to insert in the base of the ethoscope PI case, for instance, to install special lights or filters.