Shape Memory Alloy (SMA) Actuated Bi-Stable Switch

As part of my thesis research on developing a bi-stable micro shape memory alloy actuated electric switch that does not require holding power (like relays) and employs metallic electrical contacts (i.e. lower losses than semiconductor junctions), I prototyped the proposed switch on a macro scale. Two different design concepts were prototyped; a translational motion prototype with leaf spring contacts and a plunger and a rotational motion prototype with similar mechanism as the toggle switch. The prototypes were tested using relays, push buttons and external power supplies to simulate automatic switching (as shown in the videos).

 

The first prototype consisted of a NiTi spring (SMA), laser-cut acrylic pieces with low friction, mechanical fasteners (to crimp NiTi springs), a copper PCB with LEDs to demonstrate electrical switching, a brass plunger and soldered stainless steel leaf spring contacts. The second prototype consisted of a NiTi spring, wood substrate, mechanical fasteners (to crimp NiTi springs), toggle switch components and a solder-able PCB with LEDs to demonstrate switching.