The prompt for this project was to make a “Prosthetic Limb.” But, we aren’t just going to make a 3D printed hand; we made a remote controlled forced arm-wrestling machine.
By using a Tens unit, an old drone, and a relay, we were able to control the muscles of someone’s arm.
The purpose of this project is to learn about mixing the human body with electronics, and our ability to deal with stimulated muscle movement.
Materials:
- We used a “TENS 7000” unit for the muscle stimulant
- A drone motherboard is for triggering the relay and an on-off switch
- And a relay
Tools:
- Soldering iron
- Wire cutters
- Wire strippers
- Electrical tape
- Possibly sand paper
Build process:
First, my partner, Johnson, and I tested out the TENS unit obviously. We had a lot of fun, and learned a lot from this experience. To learn more about the TENS unit, we talked to our biology teacher, Mr. Arthur. We asked what muscles might be used for an arm wrestling competition. Once we learned about the human body, we connected the electrodes to the right muscles in the body, and turned it on to test it.
Once we figured out where the electrodes went, we wanted the whole thing to be wireless so you can turn it on and off with the flip of a switch. To do this, we disassembled a small drone to take it’s mother board out. The motherboard directly connects to the motors, giving us over 5 volts each output. Our relay needs 5 volts DC to activate, so this was an easy win for us. Once we flip the switch on the controller, the relay activates and the electricity from the TENS unit runs freely through the relay, the connected persons’ muscles, and back to the TENS unit. Both the drone motherboard and the TENS unit use one 9 volt battery. I believe the TENS unit produces a square wave, but we haven’t been able to test it with the previously made Oscilloscope.
I lost all the photos and videos of the build due to my phone catastrophe; but, I have end result photos below.
The big blue box is the relay and green board is the motherboard. Both are sitting on the TENS unit.
Here is a video of it in action,
Creative Design and Engineering 