If you hook up electrodes to a muscle — say, in your forearm — they can read the electrical signals generated when you flex that muscle. It’s called electromyography, or EMG, and in the hands of Greg Gage, it has hilarious effects.

Gage is a hacker and Maker and Co-Founder of Backyard Brains, which builds products and kits to help users and Makers understand the brain in a quite literal sense. He may be most famous for his experiments on cockroaches. By placing a chip on the back of a cockroach and connecting an electrode to the roach’s antennae, he was able to “drive” the roach, or at least get it to turn to the left or the right on command.

The genesis of this particular experiment was thanks, in part, to PETA, which objected to Gage’s similar experiments. So he built a similar experiment, using people. He used an Arduino to multiply the amperage received from the electrodes, and pumps it back into someone else’s muscle via a system called a transcutaneous electrical nerve stimulator. When you’re hooked up and your partner clenches her fist, you can’t help but do it too.

“If you ever have issues where someone says, ‘You don’t just understand me anymore,’ now you have an invention that allows you to feel what someone else feels,” says Gage.

Gage attended MakerCon this week, participating in a panel on neural interfaces for Makers. Between the rise of wearables and the plummeting cost of technology, using your brain — and the data you can get from it — has never been easier.

“Today our labs look much, much different,” Gage says, noting the prevalence of Arduinos and 3D printed parts you’ll find in modern neuroscience labs. More than ever, amateur, non-academic neuroscientists can do their own experiments, both reading brainwaves, and stimulating them.

Visit Backyard Brains to see detailed instructions on making your own Human to Human Interface, and many other projects.