ATTO World Smallest Arduino Compatible Development Board

ATTO World Smallest Arduino

Arduino Atto is a small-sized, low-powered microcontroller board designed for use in small-scale projects and prototypes designed by Nionics. It is based on the ATmega32U4 microcontroller and has 12 digital input/output pins, as well as 4 analog input pins and a reset button.

Arduino Atto boards are compatible with the Arduino programming environment, making them easy to use for beginners. They are often used in projects that require a small form factor or low power consumption, such as wearable technology or remote sensors.


  • Dimension0.40″ x 0.45″ (10.3 mm x 11.5 mm)
  • Weight0.04 oz (0.68 g)
  • MicrocontrollerATmega32U4
  • Operating Voltage3.3 V
  • Input Voltage4 – 13 V
  • Digital I/O Pins12 + 3 (RGB LED)
  • PWM Channels4 + 3 (RGB LED)
  • Analog Input Channels 4
  • Interface USB, SPI, I2C (TWI), ISP
  • Peripherals Reset button, RGB (rainbow) LED
  • Bootloader Arduino Leonardo
  • Flash Memory32 KB (ATmega32U4) of which 4 KB is used by the bootloader
  • SRAM2.5 KB (ATmega32U4)
  • EEPROM1 KB (ATmega32U4)
  • Clock Speed16 MHz
  • Pin Pitch0.05″ (1.27 mm)


  • Very small size
  • Suitable for prototype wearable devices like smartwatches


  • Pin incompatible with breadboard
  • Board manufacturing quality doesn’t look good in photos

Pinout Diagram

Size Comparison

Comparing the dimensions of Arduino ATTO to Arduino UNO, Arduino Nano, and Seeed Studio XIAO

comparing size of Arduino atto o other Arduino boards and xiao
Which Board Will You Choose For Your Wearable Project?

1 thought on “ATTO World Smallest Arduino Compatible Development Board”

  1. ATTO or PICO,they both seems as the same size and same ideea,problem is that not even 1 of them can be bought from anywhere,so,it deasn’t matter how small it is if is not in any store

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