Backyard Brains

Safety and Comfort Precautions to be Implemented in the Backyard Brain Demonstration

  1. Assure that parental consents have been submitted on behalf of the volunteering students.
  2. Select two students, one to be the “Controller” and one to be the “Muscle Controlled.” Let the Muscle Controlled student know that they will feel a tingle and a flinching of the arm, and that it may be uncomfortable to some people even though it is not particularly painful.
  3. Both volunteers are seated next to each other at a table.
  4. Hook up the Controller first, being sure to locate and secure the leads at the sites shown in the manual. Do not hook up the battery to the EMG sensor (the “SpikerShield”) until you have the other leads and wires in place.
  5. Demonstrate to the students the “myoelectric action potentials” (the electric impulses) released by the neuronal (nerve-generated) activation of the forearm muscles of the Controller volunteer on the screen of the tablet computer. Assure that the lights on the EMG sensor (SpikerShield) go up to the red light briefly each time the forearm muscles are activated.
  6. Before hooking up the Muscle Controlled volunteer, assure that the TENS (“transcutaneous electrical nerve stimulator”) unit is completely turned off and that the battery to the EMG sensor (SpikerShield) has been disconnected. Note that there are two terminals on the TENS unit. You will use only one side.
  7. The sequence for activating the TENS unit for the “muscle control” demonstration should be first to 1) hook up the TENS to the EMG sensor (SpikerShield), then 2) hook up the wires to the Muscle Controlled volunteer according to the illustrations in the manual, then 3) hook up the battery to the EMG sensor, then 4) demonstrate that the Controllers flexion of the wrist brings the lights on the SpikerShield up to the red light, and finally (with both volunteers resting their arms on the table top in front of them) turn the TENS unit up to the “2” on the dial corresponding to the wire on the unit that is connected to the Muscle Controlled volunteer while the Controller is flexing (bending forward) the wrist. Ask the Muscle Controlled volunteer to indicate when he/she feels the tingle of electricity and to speak up if uncomfortable. Turn the dial up to “3” while the Controller is flexing the wrist. If no response in the Muscle Controlled volunteer occurs, turn the TENS unit up to “4.” If still no response, turn the TENS unit up to “5.” It is unlikely that the unit will have to be turned any higher than “4.”
  8. To remove the devices, follow the reverse sequence as above. Specifically, first turn off the TENS unit, then disconnect the battery from the EMG sensor (SpikerShield), then remove the wires and disconnect all devices.
Backyard Brain's Human-Human Interface Assembly Instructions
Backyard Brain's Human-Human Interface Assembly Instructions (PDF 1.18 MB)
Backyard Brain's Human-Human Interface Assembly Materials
Backyard Brain's Human-Human Interface Assembly Materials
Ulnar Nerve Drawing
Ulnar Nerve Drawing