Shape Memory metals that were developed by NASA for the space industry, and have been used for increasing applications down on earth. For example, there have been limited studies on using these materials in robotics. They make it possible to create very light robots.
Tiny, silent, and lightweight at just 4.2 grams, NanoMuscle Rotary shape memory alloy actuators provide 60° of rotation using a linear NM70-Super memory metal actuator encapsulated in a body with a spring-loaded, cam-action rotary output. The NanoMuscle Rotary actuators come in two different versions: the 2-pin NM70R-2P, and the 6-pin NM70R-6P. The -2P actuator bounces between limit stops when connected to a power source, and the -6P provides greater control, with access to end limit sensors, and can be driven by the MADv5 (sold separately). Operating voltages are ~3-9V. Refer to the Downloads page for additional details.