But the idea persists, and from time to time we see them here at Hackaday. [Gord Payne] has one with an elegant sensor solution, it detects finger movement using a light dependent resistor.

It uses MOC3021. Front end of the circuit is powered by the 5volt dc supply available from the usb port of the PC. When circuit is powered, the light sensor LDR (R2) resistance is low if there is ...

The new TMD2755 module’s footprint of just 1.1mm x 3.25mm is some 40% smaller than that of the next smallest comparable 3-in-1 (IR emitter + IR detector + ambient light sensor) modules on the ...

The new TMD2755 module’s footprint of just 1.1mm x 3.25mm is some 40% smaller than that of the next smallest comparable 3-in-1 (IR emitter + IR detector + ambient light sensor) modules on the ...