CD4051 8-Channel Analog Mux Scanner

Three GPIOs scan eight analog inputs through a CD4051. One ADC reads them all, one channel at a time.

Difficulty: Breadboard. Estimated build time: about 30 minutes. Estimated parts cost: about US$1.80. 7-part bill of materials with live supplier pricing. A bidirectional 8-channel analog multiplexer driven by three address lines.