This is a cost-effective, 3D printable accessibility switch. The switch has a 60 mm (2.5 inch) round activation surface and uses a standard 3.5 mm cable. The switch is 40 mm in height. Using the specified switch, the activation force is about 3.4 N (325-350 gf). The cost in parts is approximately $10 in hardware and 3D printing materials.
The switch is activated by applying pressure on the top surface. This switch can be connected to any standard AT interface, and can also be used with the Xbox Adaptive Controller. The switch can be used on a flat surface or mounted using the 1/4″-20 UNC connection on the bottom.
The top button / activation surface is attached to the base by threading it on. This makes it easy to change tops to change color, labels, etc.
More details can be found on the Makers Making Change website here