Ultrasonic Headtracker Mouse

I recently rebuilt a headset for a head tracker mouse for a paraplegic chap.

This instructable contains a bit of information that might help anyone else trying to do the same.

The unit that this headset works with is the PRC Headmaster, Prentke HM-2P. Its a fairly old design but it is based around ultrasonic transducers and time of flight calculations.

Step 1: Print the Headset

3D printed using PET+ (tough and flexible).

STLs on Thingiverse or attached

Step 2: Electronics

Quite simple electronics

16mm SQ40R ultrasonic transducers

RJ11 connector

Nokia headset wire to add a flexible bit at the end (turns out they use 5 cores).

PSF 100A pressure switch (lowest pressure version)

Bits of ribbon cable to join it all

Connections numbered in the diagram

Step 3: Assembly

Mostly push fit.

Add a bit of heat shrink to protect the headphone wire.

Velcro and foam to add some padding.

Sugru to protect the exposed electronics.

Step 4: Updates

I have built a second one of these headsets, it which includes a few modifications.

.STL slightly updated for the wire to be connected up the top not side.

Parts sourced from CPC:

**SN36228 Ultrasonic reciever 40 kHz 16mm, 400SR160

**NOTE the headsets made with these ultrasonics only worked on one of the two control boxes, these may not be the best ones to use!

SN36427 Pressure Switch 0.004-0.018 PSI PSF100A-0.5