Wireless EMDR Tapper
A re-design of an EMDR therapy device at a therapist’s request.
Background
What is EMDR?
Eye movement desensitization and reprocessing (EMDR) therapy is most often used for processing traumatic memories. It involves the patient revisiting a distressing memory while a stimulus is simultaneously introduced. The type of stimulus varies from audible to physical, but the important part of it is bilateral stimulation - a practice of alternately stimulating the left and right sides of the brain.Usually when a person revisits a trauma, the logical part of the brain shuts down and lets the emotional part spiral into distress. The added stimulation from EMDR keeps the logical brain from doing that shut-down and keeps it engaged, allowing room to actually process the memory.
Further information can be found here.
TheraTapper and the Project Request
This project was requested by Lisa Jellison, LCSW, a practicing therapist in Northern California. She uses a TheraTapper in her EMDR practice, which uses vibration for the added stimulus. It consists of a control module for the therapist and two handheld paddles to be held by the patient. The paddles vibrate at varying speeds and intensities, frequently adjusted by the therapist with their control module.
Lisa has found that the length of the cables connecting the paddles to the control module can be restrictive, requiring patients to sit somewhere other than where they might feel most comfortable. Considering EMDR is used for processing traumas, comfort does have to be accounted for in this practice.
Final Product
CAD Models
How It Works
Reception
Each case contains the following:
Control Module
Seeed Studio XIAO ESP32C6
Custom PCB 1
10k Potentiometers
Neopixel
Pushbutton Switch
Handheld
Seeed Studio XIAO ESP32C6
Custom PCB 2
Vibration Motor
290 mAh LiPo Battery
Slide Switch
Control Module
The control module (CM) consists of a button and two potentiometers, of which one adjusts motor strength and the other adjusts speed/motor duration. It communicates with the handhelds via ESP-NOW, which is initiated by turning the top potentiometer a full rotation.
The CM has two possible modes: manual and random. It will always begin in manual and stay there until the center button is pressed for a few seconds, which will trigger random mode. The LED color indicates which mode is active. In order to exit random mode, hold down the button for another few seconds.*
*Exiting random does not work correctly yet and will be addressed in the future by looking into adding an interrupt to the code.
Shown with a white case for clarity. The blue/green filament alters the color appearance, resulting in LED colors of green and a slightly different green. This will be addressed in the future.
Handheld
The handhelds are very straightforward. Once switched on, they receive values for intensity and speed from the CM and power the motors accordingly. In order to keep them vibrating alternately, the code for one handheld is set to start immediately while the other is immediately delayed. They should never be active or inactive at the same time, as EMDR requires alternating stimulation.
Lisa Jellison had the opportunity to test a prototype in November and she was very happy with the product. In written feedback, she said the following:
I especially like the new designs of the light to signal power and the randomized button feature. Additionally, I like the larger size of the "paddles", as well as a designated spot for your thumb which are both original concepts from other similar products on the market to date. We have discussed color options and ideas for picking a soothing color to enhance the user experience. She has paid great attention to detail in development and implementation of this project.
I believe this tool has the potential to transcend from simply a college level project to a marketable product that could help so many people if she chooses to pursue the design concepts beyond the classroom.
Future Plans
This project is far from complete and I intend to continue iterating on it. Here are some of the things that still need to be addressed:
Case fitment
The handheld lid still doesn’t fit perfectly after components are installed. There is likely a collision with a component that is not easy to find in the CAD model.
Motor noise
While relatively quiet, the motors are currently too loud for my liking. EMDR is usually done in silence, so motor noise is not desirable, especially since the noise it not the same for the two handhelds. One is higher pitched than the other despite having the same settings.
Random Mode
As previously mentioned, exiting random mode doesn’t work right now. Technically it does, but it immediately jumps back into it. I currently use a delay to make the current randomized setting last for more than a split second - an interrupt may be appropriate here instead.
LED Color
The CM case lid needs to revert back to white, or I need to adjust the colors of the LED indicator so that the change in color can be discerned through the blue/green filament. The case color was chosen by Lisa for having calming colors and so that it would show better in photos. For practical reasons, white may be the better choice.
Control Module Battery Power
The CM is currently powered by USB only. Ideally, a battery should be introduced.
Charging
Right now, there is no indicator for battery level or for when a battery has been fully charged. Not ideal.
If a battery is introduced to the CM, that makes three individual modules that have to be charged. That’s a lot to juggle around
Solution A: Design a charging dock around a split USB cable to encourage charging the modules at the same time, for the same duration.
Solution B: Look into wireless charging. I have no experience here, so I don’t know what it entails.
Acknowledgements
Lisa Jellison, LCSW - Client
Kelli Noirot - Hardware, electrical, and 3D printing mentor
Brandon Noirot - CAD mentor
Zack Weaver - Advisor