Overview
With the Backyard Brains Human-Human Interface you will learn exciting neuroscience concepts first-hand as your brain sends an electrical impulse to your arm's muscles, telling them to move, and when your muscles move, this generates an even larger electrical signal. You'll take that electricity, then further amplify it and inject it into the nerves controlling another person's arm.
If you would like to learn more details about the kit, Please visit here.
Instruction
The Controller Part
- Step1
Plug the EMG electrode cables (RCA) into the EMG SpikerShield, matching the red, black, and white.
- Step2
Place two EMG electrodes on the forearm, one on the back of the hand, and clip on the EMG cables using the alligator clips. Red and black on the forearm muscle, and the ground (white/bare metal clip) on the back of the hand.
- Step3
Now, have the controller flex their forearm muscles. With a sufficient strong flex, your controller should be able to light up all the LEDs. If the LEDs are not lighting up, you can:
a) change the numberical value of the #define Threshold 3 statement in the Arduino code (using the Arduino Software) to a lower value to make the threshold lower. Note that you will then have to reupload this code to the Arduino if you want to change this value.
b) turn up the gain on the EMG SpikerBox by turning the orange potentiometer screw counterclockwise.
The Controlled Part
- Step1
Settting the frequency of the TENS device.
- Step2
You will then need to find the threshold of your partner. Place two surface EMG electrodes across the ulnar nerve. This runs up the back of the forearm.
- Step3
Now connect the TENS unit to the forearm with the modified TENS cable you built.
- Step4
Have your partner slowly increase the amplitude of the TENS until there is a visible change of the muscle activity. You should have the male connectors connected together with the pink jumper (this uses a different kind of connector if you followed the DIY instructions). Alternatively, you could use a non-modified TENS cable for this part of the experiment. The stimulation feels like pins and needles in your muscles. It is not terribly uncomfortable but some people may not like it.
- Step5
Now that the TENS' level is comfortably set, plug the Tens cables male header pins into the EMG SpikerShield Stimulator output.