Arduino MicroSD Data Logger

Sample a sensor once per second and write the timestamped value to a CSV file on a microSD card — standalone logging with no internet required.

Difficulty: Breadboard. Estimated build time: about 45 minutes. Estimated parts cost: about US$8.00. 6-part bill of materials with live supplier pricing. A standalone data logger that records sensor readings to a FAT32-formatted microSD card.