Download the codes here Arduino simple shield potentiometer code: Arduino shield rc car: Arduino nano module L298P code: ...

The device itself consists of an off-the-shelf ultrasonic sensor, an Arduino, and a digital potentiometer. It all fits in a custom 3D printed enclosure and runs of two rechargeable coin cells.

Call it synchronicity, or manually setting a 16-bit number in an Arduino, or how to turn an OLED into a rotary dial ...

We set the potentiometer pin as 0 (A0 on the Arduino Uno board), the CONTROL variable is the voltage that is used to cotrol the led brightness of the speed of the fan.