Muscle wire, also known as smart wire, more commonly known as nitinol or smart wire, which is the name for very high performance, shape memory alloy, actuator wires. It is made of nickel-titanium.
The nickel-titanium alloys were first developed in 1962–1963 by the United States Naval Ordnance Laboratory and commercialized under the trade name Nitinol (an acronym for Nickel Titanium Naval Ordnance Laboratories). Their remarkable properties were discovered by accident. A sample that was bent out of shape many times was presented at a laboratory management meeting. One of the associate technical directors, Dr. David S. Muzzey, decided to see what would happen if the sample was subjected to heat and held his pipe lighter underneath it. To everyone’s amazement the sample stretched back to its original shape. Source Wikipedia
What can it be used for? – smart wire can be used in electronics, cars, medical and in smart materials. It can expand or contract, ideal for smart textiles and model-making projects. On passing a current through the composition of the wire changes which makes it contract. This movement can be increased using levers to produce moving parts within models.
Movement can also be controlled using a 555 timer circuit with a supply voltage of 4.5V, this allows the correct 3V to operate the wire. Movement can also be controlled using PIC chips to activate and de-activate the muscle wire using the correct 3V supply.
Light Stitches muscle wire has fitted crimped copper ring terminals to make model making simple. The wires can easily be soldered on to the copper ring terminals. Smart wire can be repeatedly used. Approximate diameter 0.015 mm.
Images show the variations available