MCP41010 SPI Digital Potentiometer

Replace a hardware trim pot with a 256-step digital potentiometer controlled over SPI — set the wiper position from code and read it back the same way every time.

Difficulty: Breadboard. Estimated build time: about 40 minutes. Estimated parts cost: about US$5.20. 5-part bill of materials with live supplier pricing. An MCU-driven digital potentiometer: an analog circuit element whose wiper position is set by a single SPI command from your microcontroller.