Solder each pair of IR LED's and sensors to one of the single ethernet ports: red leads (+) to pin 1, black leads (ground) to pin 2, one yellow lead (sensor 1) to pin 3 and the other yellow lead (sensor 2) to pin 4.

Solder a jumper wire to the corresponding pin on the 6-way ethernet port for each sensor, and a normal wire each for + and ground. WARNING: ETHERNET PINS DO NOT ALWAYS MATCH UP BETWEEN BRANDS SO CHECK THE CONNECTIONS WITH A MULTIMETER!!

Solder jumper wire to each LED anode pin, and a 330 ohm resistor to the cathode pin; then a wire to the resistor.

Jumper wires make it easy to connect to the Arduino I/O pins, but there aren't sufficient ground or 5V pins, so you need to use normal wires, then solder those together.

Any exposed regions can be shielded with heat-shrink tubing or electrical tape if there is any concern of movement/contacting other bits.

Plug the collated ground wires into the Arduino Ground pin and the collated + wires in the Arduino 5V pin. Then plug the other jumper wires into the correct I/O pins:

Pilot LED's - 2-13 (in order)

IR sensors - 22-45 (in order of sensor pairs)

Download the .ino file and upload the code to your Arduino Mega.

Print 4 sensor holders for each cage (ie. one each for every IR LED or sensor). There are 2 .stl files included in the project - one as pictured to hang from the rail on a Tecniplast cage, the other has a hole for gluing in a neodymium magnet to allow for magnetic attachment. The sensors can then be slotted ready for placement on the mouse cage.

Plug the ethernet cables in to the correct ports to connect each pair of sensors in order.

Download and install "Putty" on the computer that is connected to Arduino. This is an open-source terminal program that will log data from the Arduino into a .csv file.

https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

Set the terminal program to log data with a data transfer rate of 115200. You need to set the correct "COM" port for the Arduino (check "Devices" in your control panel). Name your file and press "Open". The program should start recording.