Watch this sweat-powered wearable control a prosthetic leg

You may not know this but your body is teeming with a powerful biofuel. The problem is scientists just haven't really been able to harness it, until now. [MUSIC] Researchers at Caltech have created what they say is the first electronic skin that doesn't require a battery. It runs on sweat. We've seen these skins before. They're essentially stretchable electronics that are meant to mimic living skin. The idea is they can be used as a sort of wearable just like a smartwatch to monitor your health and control devices. Up until now they've always needed an external power source. But Caltech scientists developed this one to run on lactate. Which is a byproduct of human sweat. So sweat surprising contains high level of chemical fuels that is especially lactating. That's Dr. Wei Gao. He says that skin is packed with sensors that can monitor things like heart rate, body temperature and blood sugar. It's also equipped with a low powered Bluetooth transceiver. You can see it there in the back of the photo. That's how they connected the skin to a couple of prosthetic devices. Watch this. Wearing the skin on her arm, she's able to control that leg. Here the skin is placed on the human arm connected to two other sensors. The skin is wirelessly controlling the motion of the robotic arm in real time. So what was that like when you first saw that your device was actually able to control the prosthetic? It feels so excited in the beginning we were weren't worried about the well, these might still need a battery. We probably needed, charging the battery and eventually when we see all we really don't really need a battery we unconfuse your power system and wireless control. The robotic arm first the leg with you really well. So excited I still remember that feeling right now. Now gal says the sensor can generate power for several days off of sweat. Next he wants to develop a variety of new sensors that can be embedded in the skin. Anything's there are low cost ways to make this available to the public. This actually could potentially be mass produced by using printing, you know, inkjet printing or laser printing is really low cost. We can prepare this on the plastic film and make like a really suitable for like a commercialization or consumer use. Of course the big picture here for the consumer is a really exciting part I mean, the idea of a sweat powered fitness tracker is pretty much a no brainer. I just wouldn't count on that on the next version of the Apple Watch.