A "silver bullet" pill powered by your own stomach acid will send health data from inside your body to your phone.
It is believed the tiny pill could revolutionise medicine by constantly monitoring your health and administering medicine, Daily Mail reports.
Researcher Dr Phillip Nadeau, from Massachusetts Institute of Technology, said: "The self-powered pill would monitor your vital signs from inside for weeks.
"It sits there making measurements and transmitting them to your phone."
The creation was unveiled at the world's biggest science conference in Boston.
It was inspired by a lemon battery which uses citric acid to charge a zinc nail and copper penny electrodes.
A version of the pill, that powers up when a zinc electrode interacts with stomach acid, was tested on pigs.
Small sensors continually monitor temperature and heart rate.
The 30mm-long device took six days to travel through the digestive tract of a pig.
Scientists want to create a smaller version of the pill for humans - the prototype measures 10mm.
The version with star-shaped arms is designed to stay in the stomach without risking blockages.
Brigham and Women's Hospital's Giovanni Traverso said: "Taking a capsule once a month could change how we think about delivering medication."