Muscle-wire cabinet lock

A very odd little thing. I initially thought that this was based on a magnetic latching system, but it turns out that it uses a length of a special wire that contracts significantly as it heats up.

It means that this unit is very simple with a minimum of mechanical parts and is not influenced by a strong external magnetic field as some magnetic units are.

The wire is theoretically rated for millions of cycles with this small controlled movement.

Although rated for a higher voltage, I tested this with 1V to slow down the actuator movement.
The electrical data at 1V is:

Cold resistance 2.86 ohms (350mA at 1V).
Hot resistance 2.5 ohms (400mA at 1V).

The unit is normally rated for 3 to 5V.

The unit only energises the wire for the length of time it takes to release the catch, as there is a switch inline with the muscle wire.

As with many items I've been buying recently, this one came from AliExpress (not a sponsor)
Here's a non affiliate link to the listing.
https://www.aliexpress.com/item/1005005211494161.html
The cost should be around £2.50, and it may appear as a bundle deal item.




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