A successful run with a 3 pulley unit. The initial length of the assembly was 8.2cm, and it contracted several times to 6.1 cm, 2.1cm of stroke. This measurement ignores the stroke produced by the first and last pulleys, so the actual total stroke should be 50% higher, or about 3cm The hook swings around, making the measurement of the total stroke less accurate, but I measured 2.7cm.

The .25mm SMA wire I used is rated for a load of 891g.

The wire is travelling around the pulleys causing the assembly to twist around. The next prototype is going to have deeper pulleys and less clearance between the pulleys and the support.