Encoders

Quadrature encoders count relative motion indefinitely, absolute encoders retain position through a power cycle, and potentiometers give an analog voltage with hard end stops. The rotation model matters before you look at the pinout.

Bare EC11 quadrature encoders, I2C navigation encoders, absolute AS5600 and 8421 encoders, slide and ribbon potentiometers, and digital I2C pots — covering most ways to read angular or linear position.

• Bare quadrature parts (Adafruit Rotary Encoder + Extras, Fermion EC11 module) need two GPIO and interrupt or debounce handling; the ANO Rotary Navigation Encoder's STEMMA QT adapter moves all of that to I2C at 0x49 and adds directional buttons.
• Absolute position survives power loss: the Grove AS5600 12-bit magnetic sensor and DFRobot Fermion 8421 encoders (16 coded detents) hold their reading without homing — incremental encoders cannot do this.
• The potentiometer branch — 10K dial pots, the Circular SoftPot ribbon sensor, the Gravity 3600° analog rotation sensor, and an ultra-thin 0.45mm graphene flexible pot — gives an analog voltage but has travel limits.
• DS1841 and DS3502 I2C digital 10K potentiometers remove the physical control entirely; the 400 P/R incremental photoelectric encoder is a motor-shaft sensor, not a panel knob.