Jim Mielke invented a device that is implanted into your skin. He made it to enter the Greener Gadgets Design Competition in 2008.
The implant is inserted into the arm through a small incision, and lies beneath the skin just above the muscle.
After it is inserted, tubes from the device are attached to a vein and an artery.
This allows blood to flow into and out of a small battery on the back of the device.
Thus your blood components, glucose (sugar) and oxygen are converted into energy.
The Tattoo interacts with your other devices such as your cell phone. A touch display appears on your arm allowing you to enter a phone number.