Circular Soft Potentiometer (Ribbon Sensor)

These circular ribbon sensor soft potentiometers, made by Spectra Symbol, are great little controllers with an adhesive backing. The circular shape has a donut - shaped sensing region with an outer diameter of 55.96mm (2.2in) and an inner diameter of 35.63mm (1.4in). There's a nominal 10K resistance across the two outer leads. The middle pin's resistance changes as you press different parts of the strip. When no pressure is applied, the middle pin floats, so use a 100K ohm weak pullup. To use, connect one side pin to ground through a 10K resistor in series and the other side pin to your power line (3V, 5V etc) through another 10K resistor in series. Then read the analog voltage on the center pin, which ranges from 1/3 Vcc to 2/3 Vcc. Never connect directly to Ground and Power!

Using this circular ribbon sensor soft potentiometer is easy. First, make sure to use a 100K ohm weak pullup as the middle pin floats when there's no pressure. To set it up, take one side pin and connect it to the ground through a 10K resistor in series. Then, connect the other side pin to your power line like 3V or 5V, also through a 10K resistor in series. You can then read the analog voltage on the center pin, and it'll be between 1/3 and 2/3 of your power supply voltage. Remember, don't connect the pins directly to the ground and power. As for maintenance, keep it in a dry and clean place. If it gets dirty, you can gently clean it with a soft, dry cloth. Avoid applying excessive pressure on the strip as it might damage the sensing region.