TM1638 8-Digit Display + Button Module

One chip drives eight seven-segment digits, eight LEDs, and reads eight push-buttons — a complete user interface over three wires.

Difficulty: Breadboard. Estimated build time: about 35 minutes. Estimated parts cost: about US$7.00. 4-part bill of materials with live supplier pricing. A complete pocket user interface in a single Titan Micro TM1638 "LED & KEY" module.