The sensors Proteus makes are called Helius, and they are made of copper, silicon, and magnesium. They're swallowed to capture information in your body for a few minutes to show how well medicine you're taking is working. They can also show doctors whether or not patients are taking their pills regularly. It is FDA approved. Proteus is working to add Helius to the pills prescribed by doctors rather than standalone sensors.
The sensor doesn't have an antenna or a battery. Instead, it uses stomach acid and fluids to power it, and it beams the results to smart devices.
Proteus also makes a patch to receive information from the Helius sensor, detect heart rate, activity, and rest. The patch then transmits information to your phone or tablet.