Photograph and description of our prototype

This photograph shows the current stimulus device and all the wiring and components.  A link to most of these components can be found in the parts list.  #9, #12, #13, #14a, and #14b have recommendations but you have the option to locally source these components.

1. Adafruit PyGamer.  I think the name is derived from Python-GameBoy. You can actually play games on it (and write your own games) but not at  the same time as you are running the tremor software.  The full specification can be found from the link in the parts lists.  All the cables are on sockets so no soldering!  Apologies for not powering it up so the LCD screen was easily visible. It also contains a rechargeable battery, and a Micro-SD slot for recording tremor data.
2. Is  a USB cable.  The end that plugs into the PyGamer is a Micro USB port.  Choose a cable that  will plug into your PC/Mac/Linux computer and has a Micro USB connector on the other end.  You will need this cable to load the tremor software onto the PyGamer.
3. 3a provides power and control to the Solid State Relays (10).  Red for power, Black for ground, and 2 white cables are the controller wires.  One white cable is part of the port/connector cable that supplied power and ground.  The other white cable comes from the other port.  3b is the power and ground from the second port and are not used.
4. Is the JST PH to JST SH Cable - STEMMA to QT / Qwiic - 200mm long.  This cable supplies power, ground, contro, and data to the Inertial Measurement Unit (IMU), since it is quite short, we have extended it via #5 and #7 to make it easy to use.
5. Is a Qwiic Adapted to allow us to connect a longer cable (#7) between the PyGamer and the IMU.
6. I made a mistake when labeling the image.  There is no #6.  Sorry!  ;-(
7. Is a 500mm Qwiic cable.  Sockets both ends so again, no soldering!
8. Is the IMU.  There are two options for this component in the parts list. One includes a magnetometer that is not used by the tremor device.  The IMU in the image is the one with the magnetometer.  It was the only one available at the time due to the worldwide silicon chip shortages.  Either IMU will work.  The IMU contains a 3 axis accelerometer and a 3 axis gyroscope.  This is the component that actually measures your tremor.
9. This is a cinch strap.  The IMU is sewn to this strap. It all looks rather mundane but it is quite important. A firm mount is a must to get good repeatable measurements of your tremor.  You need to be able to easily position the IMU on the back of your hand in the same position every day.  The cinch strap, as illustrated, can be adjusted for larger or smaller hands.  There is very little ‘give’ in the strap providing a firm base for the IMU. An alternative would be to use a glove and attach the IMU to it.
10. Are the Solid State Relays.  There is a pair of them. Under software control, these SSRs switch the electrical stimulation provided by the TENS Unit (#15),  between the Median and Radial nerves delivered via the electrodes #14a and #14b
11. #11a adn ##11b is the two sets of leads that are compatible with your TENS unit.  You need  two sets of these leads.  #11a is used to deliver the TENS stimulus to the SSRs (#10) and provides the ‘return path’ via electrode #13.  #11b supplies the TENS signal from the SSRs to the Median and Radial nerves via electrodes #14a and #14b.
12. Is a short jumper wire to connect the TENS output to both center taps of the SSRs.
13. Is the ‘return path’ electrode which should be attached to the back of the wrist.
14. ‘a’ and ‘b’ are the two electrodes that deliver the stimulus to the Radial and Median nerve.  These should be attached to the underside of the wrist.
15. TENS unit. Transcutaneous Electrical Nerve Stimulation (TENS) therapy involves the use of low-voltage electric currents to treat pain.  Because the TENS unit can produce a safe stimulus, it is used by the tremor device to stimulate the Radial and Medial nerve. 

Please Note: This device is not an FDA-approved system or device. The FDA’s responsibility is to regulate products on the commercial market and help safeguard the public. It’s not manufactured or sold anywhere in the world. It’s an open-source designed system that you can choose to build yourself. The FDA doesn’t currently regulate self experimentation. Individuals who build this device are essentially doing an (N=1) experiment, which they have a right to do by themselves, on themselves. If you decide to build anything described herein, you do so at your own risk.

(Please note: This information should not be used as a substitute for medical treatment and advice. Always consult a medical professional about any health-related questions or concerns.)