Arduino Pro Mini ATmega328 Compatible — 3.3V/8MHz or 5V/16MHz
The Arduino Pro Mini is the smallest ATmega328-based Arduino-compatible board: no USB chip, no barrel jack, and no USB connector — just the microcontroller, voltage regulator, and crystal on a 18 x 33mm board. Programming requires an external USB-to-TTL adapter connected to the six-pin serial header. The 3.3V/8MHz variant runs directly from a single LiPo or three AAA batteries; the 5V/16MHz variant matches the Uno’s performance in a fraction of the footprint.
- ATmega328P — 32KB flash, 2KB SRAM, 1KB EEPROM
- Two variants — 3.3V/8MHz for battery projects, 5V/16MHz for standard power
- No onboard USB — programs via external FTDI/CH340 USB-TTL adapter
- 14 digital I/O pins — 6 with PWM
- 8 analogue inputs — A0–A7 (10-bit ADC)
- 18 x 33mm board — smallest ATmega328 Arduino form factor
| Specification | Value |
|---|---|
| Microcontroller | ATmega328P |
| Variants | 3.3V/8MHz or 5V/16MHz |
| Flash memory | 32KB (2KB bootloader) |
| SRAM | 2KB |
| Digital I/O | 14 (6 PWM) |
| Analogue inputs | 8 (10-bit) |
| Programming | External USB-TTL adapter (not included) |
| Board size | 18 x 33 mm |
Do you need a special programmer for the Pro Mini?
Yes. Without onboard USB, you need an external USB-to-TTL serial adapter (CH340, FTDI FT232, or CP2102) connected to the Pro Mini’s 6-pin FTDI header — TX, RX, GND, VCC, DTR. The DTR line resets the board automatically when the IDE uploads. In the Arduino IDE, select the matching Pro Mini board and processor (ATmega328P 3.3V/8MHz or 5V/16MHz).
How long does the 3.3V Pro Mini run on batteries?
In deep sleep mode using the LowPower library, current drops to under 5 microamps. Two AA batteries (3000mAh combined) can power the board in sleep-wake cycles for over 12 months, depending on how frequently the sketch wakes and what peripherals are attached.
Best for
Battery-powered sensor nodes, wireless sensor networks, wearable microcontrollers, remote environmental loggers, space-constrained enclosure builds, custom PCB integration, and any project where the Nano is still too large or consumes too much power.
Why Kunkune
Shipped from UK stock. 60-day returns, no minimum order. Fast Royal Mail delivery.
Buying in bulk? For orders of 10+ units, contact us for trade pricing.
