Amputees in developing nations frequently can't afford the high-end prostheses used by people in other parts of the world. That's why Technological University of Mexico spin-off company Protesta is developing a low-cost artificial arm made from lightweight polyethylene terephthalate (PET) plastic. As an added bonus, the arm will alert the user if it gets too hot.

The present prototype contains a total of 40 heat sensors – 15 in the hand, and 25 along the length of the arm. These are calibrated to 35 ºC (95 ºF), just below normal human body temperature.

If they're exposed to significantly higher temperatures, they convert the resulting thermal energy into electricity. That is in turn used to used to activate a vibrating motor in the socket of the prosthesis, which the user feels in their stump. The idea is that they will then be able to take action before the prosthesis is damaged, or before the heat radiates through it and into their own skin.

Additionally, the hand of the device protects itself by automatically closing when excessive heat is detected – hopefully not closing around the source of the heat in the process.

Project leader Carlos Perez Roque claims that the arm is capable of lifting up to 8 kg (17.6 lb), and that it should ultimately retail at US$2,000 for just the hand and wrist, or $2,500 for the entire limb.

Source: Investigación y Desarrollo (Spanish)