74HC4511 BCD-to-7-Segment Driver

Drive a 7-segment digit directly from four binary signals — the original chip-and-a-display way to show numbers before TM1637 modules existed.

Difficulty: Breadboard. Estimated build time: about 22 minutes. Estimated parts cost: about US$3.20. 6-part bill of materials with live supplier pricing. A single 7-segment display that lights up one decimal digit (0-9) based on a 4-bit binary input on pins A, B, C, D.