SparkFun Touch Potentiometer

Description

The SparkFun Touch Potentiometer, or Touch Pot for short, 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 microcontroller 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 such as volume control and LED dimming.

The Touch Potentiometer is controlled by a Microchip PIC16F1829 8-bit micro-controller that provides the host interface, LED control, capacitive sense and peripheral control functions. A built-in low-dropout voltage regulator allows operation over a range of input voltages up to 12V and breadboard friendly connectors make it easy to play with. A desktop application has been created by our collaborator, Dan Julio, that communicates with the Touch Pot over a serial connection. From this utility app you can change configuration settings, alter LED behavior, calibrate the capacitive touch sensor, view current readings in jabber mode, and much more.

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
• Built-in 5V LDO voltage regulator
• Through-hole and SMT connectors

Documents:

• Schematic
• Eagle Files
• User Manual
• Hookup Guide
• Datasheet (AD5262BRU)
• Touch Pot Utility Application
• Source Code
• GitHub (Design Files)
• Product Page
• Product Video