When you turn Ojarumaru Man on, he says something (in Japanese) about the firefly on his hat and waves his tiny, 9-gram plastic arm up and down through 60 degrees of motion. Because of O-Man's peaceful, Zen-like demeanor, engineers wanted a completely silent method of actuation that would be cost-competitive with an inexpensive, single-speed motor. (In fact, the original design called for a traditional electromagnetic motor, but engineers rejected it because it was too noisy.) In this simple application, engineers mounted Oman's arm to the output shaft of a Nano-Muscle RS-70-CE actuator, which runs off of two AA batteries and uses shape memory alloys (SMAs) as the motive force. SMAs undergo a solid-state phase change when their temperature drops below a specific transition point, providing constant power output across the entire stroke length and a force-to-weight ratio on the order of 15 kgf/m2.
Nanomuscle offers a new commercial development kit for its RS-70-CE actuator for $199.95 or toy development kit for $179.95. For details, go to http://rbi.ims.ca/3849-563