Introduction: Superficial EMG Device for Neuro Rehabilitation

By Utah Assistive Technology Progam
About: The Utah Assistive Technology Program (UATP) is part of the Institute for Disability Research, Policy & Practice at Utah State University. Our mission is to put assistive technology into the hands of people wh…

The goal of this project is for patients going through upper limb rehab who are having a hard time reconnecting brain to upper limb movement. This device senses small muscle intentions and outputs the signal to a servo motor movement. This can be beneficial to occupational therapists or physical therapists who are working with these patients as they strive to strengthen that biofeedback loop.

Attachments

Supplies

  1. Muscle BioAmp Patchy sEMG board (1) (click here for link)
  2. Electrode gel pads (3 per device use)
  3. Electrode cables (3)
  4. Arduino Micro (1)
  5. 9V battery with connector (1)
  6. Servo (1)
  7. Rocker switch (1)
  8. Potentiometer (1)
  9. 3D printed case or equivalent (1)
  10. Assorted jumper and extension wires

Step 1: Build the Circuit

9V Battery and Switch

  1. Put the positive side of the 9v battery on one side of the switch
  2. The negative side connects to the GND Arduino pin
  3. The other side of the switch connects to the Vin Arduino pin

sEMG Board

  1. VCC → 5V Arduino pin
  2. GND → GND Arduino pin
  3. OUT → Arduino pin A0
  4. REF → one of the electrode cables
  5. Pad 1 (IN +) → second electrode cable
  6. Pad 2 (IN -) → third electrode cable

Servo

  1. (+) → 5V Arduino pin
  2. (-) → GND Arduino pin
  3. Signal → Arduino pin 10

Potentiometer

  1. (+) → 5V Arduino pin
  2. (-) → GND Arduino pin
  3. Output → Arduino pin A1

Step 2: Program the Device Using Code

Attached is the code that you can upload

Attachments

Step 3: How to Use

Now that the device is built and programmed, it is ready to be used. The first step is to

  1. Attach the 3 electrode pads to the target muscle area:
  2. Place two electrode pads along the fibers of the target muscle, with the edges of the pads touching or within ¼ inch of each other.
  3. Place the third pad on an area that doesn't have much muscle activation, such as just above the elbow over the tendons that are there. 
  4. Then, connect the first two pads to the two electrode cables attached to (IN +) and (IN -) on the sEMG board.
  5. Finally, connect the third pad to the electrode cable coming from the REF pin. 
  6. Power on the device, and the servo should start moving with the activation and flexing of the target muscle.


*The sensitivity can be adjusted using the potentiometer to achieve optimal device performance.

*If the arduino is attached to a computer, the Serial Plotter tool in the arduino IDE can be used to further visualize the muscle signals being generated.