I needed a rotary encoder — I pulled a cheap one out of one of those “49 boards for Arduino” kits you see around. Not the finest encoder in the land, I’m sure, but it should do the job.

It works by using two absolute rotary encoders that each have a whopping 1024 positions available. One encoder is stuck into the South Pole, and it reads the lines of longitude as the user spins ...

byte enc1oldPins = 0; // will hold state of pins last time encoder was read byte enc2oldPins = 0; byte enc1newPins = 0; // will hold new encoder pin reading, to be compared with last time's pin states ...

8 comments on “ Rotary encoder with absolute readout offers high resolution and low cost ” chasash February 5, 2013. Anyone remember Selsyns – this reminds me of the DC equivalent (who's name I can't ...

The scroll wheel will need to work via a rotary encoder and not an IR transmitter/detector; see the source post or the video tutorial for more details and how to spot the difference.