Original Touch Potentiometer

Available at tindie (and now in a digital-only version). The digital-only version does not include the AD5262 chip and has white LEDs.

This is the original design for the Touch Potentiometer and formed the basis for the Sparkfun collaboration . It is functionally identical to the Sparkfun version other than the color of the LEDs and requires a 5V power supply (does not have a built-in regulator). It works with the same demo sketches and tputil program.
Front and back of danjuliodesigns version of Touch Pot PCB
Touch Pot block diagram
The Touch Potentiometer is an intelligent linear capacitive touch sensor that implements potentiometer functionality with 256 positions. It can operate as a peripheral to a computer or embedded micro-controller or in a stand-alone capacity. The Touch Potentiometer provides both a dual-channel analog and PWM output for direct control of other circuitry. Configurable analog and PWM transfer functions support a wide variety of applications.

Features


  • Dual host interfaces: Logic-level serial and I2CTM
  • Dual 8-bit 20 k-ohm 3-terminal digitally controlled variable resistor outputs
  • PWM output
  • 8 LED display with multiple display modes and intensity levels
  • Option for interpolated (soft) changes between touches
  • Configurable touch sensor parameters for a variety of PCB covers
  • Easily configurable I2C address to allow multiple devices on one bus
  • Configurable linear or non-linear PWM transfer function
  • Configurable linear or simulated logarithmic variable resistor transfer function
  • Variable resistor supports single- or dual-supply operation
  • Simple register interface with jabber option
  • Programmable power-on default operation
  • Built-in calibration procedure
  • User-accessible EEPROM data storage

Applications


  • Analog potentiometer replacement
  • Stereo channel audio level control
  • Computer peripheral
  • Embedded system control
  • Dimmer for LED lighting applications
  • DAC replacement

Downloads


Touch Pot dimensions
tputil program

tputil program

User and programming manual.