Arduino Micro vs Nano: Pinout, Size & Power Differences
Arduino Micro packs the same ATmega32U4 chip as the Leonardo in a 48 mm board; Nano uses the older ATmega328P on a 45 mm PCB. Both run 5 V logic, but Micro has native USB-HID support while Nano needs an external FTDI chip for serial.
Builders grab whichever is in stock and later regret it: Micro fits inside game-pad shells for custom controllers, while Nano slips into quadcopter arms where every millimeter counts. One missed pin or power jumper can scrap an entire weekend build.
Key Differences
Micro gives you 20 digital I/O plus 12 analog; Nano offers 14 digital and 8 analog. Micro draws 29 mA idle, Nano 19 mA. Micro’s onboard micro-USB powers the board; Nano needs 5 V on VIN or 6–20 V unregulated. Size: Micro 48 × 18 mm, Nano 45 × 18 mm.
Which One Should You Choose?
Pick Micro if you need keyboard/mouse emulation or HID projects; choose Nano for ultra-low power drones or breadboard prototyping. Both cost ~$20, but stock shortages often decide for you.
Examples and Daily Life
Slap a Micro inside an old SNES controller to create a plug-and-play USB gamepad. Drop a Nano into a glove-box to read OBD-II data on the go. Either fits a mint-tin case for stealth IoT hacks.
Can I swap them without rewiring?
No—Micro’s SDA/SCL pins sit at 2/3, Nano’s at A4/A5. Always check pinout before hot-gluing.
Which one sips less battery in sleep?
Nano wins; it drops to micro-amps with the right low-power library, while Micro stays above 5 mA due to USB oscillator.
Are shields compatible?
Only if you use adaptor plates; Nano needs headers, Micro matches standard 0.1″ spacing but lacks shield form factor.