Hi Muhammad,
They are both SMA (Shape Memory Alloy) and they are formed in different ways. The Nitinol would need to be formed in the shape you want at a temperature as high as 300 degrees Celsius. When cooled, you can bend it any you want, but once you apply a little temperature (20 to 40 degress Celsius) or current through the wire, then it will return to its original form.Flexinol is already pre-formed. Upon adding heat or passing current through it, it will shrink in length from 6-8%. The passing of current through the wire is what heats the wire, they are of low resistance (typically 6 to 10ohms). At 5V this would mean 0.5A up to 0.833A. This is a little beafy alright, but you can pulse this or PWM this wire. Control is through either a high side or low side transistor (BJT or FET). In situations like this, I typically like low side switching P-Type FETs, but you have to beware of the RdsOn value. If it's too high, it will become a voltage divider and more power will be drawn by your FET than the muscle wire. To be honest, I'm not really sure if it is suitable for your project. It might do the job, but there's a lot of problems to sort out with it.-Mike
