QWOP was a flashgame released by [Bennett Foddy] in the distant past. Players would use individual keys to trigger muscle spasms in their character’s legs, attempting to sprint as far as possible without hitting the ground. Hackaday alumus [The Hacksmith] wanted to recreate this in real life, and set to work.
Initially planning to hack some TENS units to cause muscle contractions, instead a pair of lithium batteries were used. Supplying up to 48 volts through a MOSFET using PWM control, it’s quite effective at triggering muscle movement, albeit with a slight pain factor. With the MOSFETs under the control of an Arduino fitted with a USB keyboard, it allows a player to control [The Hacksmith]’s leg muscles, albeit without much finesse.
While the jumps are just video magic, the players do succeed in making some purposeful spasms happen. It’s about as effective as our attempts to play the original game, anyway. Don’t try this at home if you’d like to avoid possible burns or nerve injuries! It’s not the first moderately dangerous build we’ve seen from [The Hacksmith], either. Video after the break.
[Thanks to NoxiousPluK for the tip!]
they’d get some “intereting” results by swapping a couple of those electrodes
Tip: look into the electrostim world for more info on doing this safely.
Protip: do not google Electrostim at work.
Ignorance is bliss?
This contraption seems to be putting DC cuttent through your body, which is a very bad idea.
DC current through flesh creates nasty stuff in your cells.
As a simple experiment, take a glass of water, a bit of regular salt to make it conductive and put some DC durrent through it, and look at the mess you’ll create.
For a better explanation, go talk to a (bio) chemist.
To make this a lot safer, add little H-bridges to the circuit for the output and make sure your body only receives AC currents. AC currents do not have these electrolysis effects.
Also: higher voltages help overcoming skin resistance and give more consistent results, but combine it with a series resistor to limit the current.
Try something like 60V to 80V with a series resistor of 1k to a few K Ohms.
Don’t put salt in an electrolysis experiment like this. You’ll create chlorine gas.
And venting a bit of choline gas into the atmosphere is several orders of magnitude less harmfull then releasing it inside the cells of your body.
The electrolytes in your body are not well suited for conducting DC current.
The electrolytes in your body are not well suited for conducting DC current.<
I find that statement confusing. Didn't your brain and nervous system use those same electrolytes so you could post your comment?
I often experiance debilitating cramps, a lot of cursing ensues. They would have to crank up the power to experience, what I experiance.
My first thought was, Too bad hooking the tens pads to their home theater amp speaker outputs presents a real risk with isolation from line/mains current.
Could make a dance contest interesting.
But then the idea of MIDI programming made me curious what they could do with this concept.
Maybe something like a pacemaker for walking, when someone has a medical issue that interferes with “normal” walking?
Many years ago, I saw some web sites where people were hooking household stereo gear to their tens pads.
Ohhh, no more sub-woofer needed!