This rotary or "shaft" encoder is an angular measuring device. It is used to precisely measure rotation of motors or to create wheel controllers (knobs) that can turn infinitely (with no end stop like a potentiometer has). With Octopus Electronic Bricks, you can quickly build electronics projects just as easy as connecting bricks. By using Octopus electronic bricks, you may connect Arduino or Freaduino compatible boards easily with various digital, analog and I2C/Uart interfaces. These the breadboard-less firm connection are prepared to extensive modules like poteniometers, sensors, relays, servos even buttons, just plug and play.