Arduino Pro Mini 328 – 3.3V/8 MHz

The Arduino Pro Mini 328 is a minimal-design Arduino board running at 3.3V with the 8MHz bootloader, built around SparkFun’s compact “Pro Mini” form factor rather than the standard Uno layout. Its small size and low pin overhead make it suited to permanent installs and space-constrained projects rather than general prototyping.

Unlike beginner-oriented boards, it ships without connectors populated, so headers, wires, or connectors can be soldered in whatever orientation best suits the final build — a deliberate trade-off that favors flexibility over out-of-the-box convenience.

Because it lacks the beginner conveniences of a fully-populated board (and requires an external USB-to-serial adapter to program), first-time Arduino users are generally better served starting with an Uno R3 before moving to the Pro Mini for space-constrained builds.

Features:
1. Compact “Pro Mini” form factor
2. 3.3V operating voltage
3. Runs the 8MHz bootloader
4. Connectors not pre-populated — solder your own orientation
5. Suited to space-constrained, permanent-install projects
6. Not recommended as a first Arduino board for beginners