Pololu 3pi Robot

Product Code:
£94.74 £78.95
  • Buy 5 for £81.00 £67.50 each and save 15%

The Pololu 3pi robot is a complete, high-performance mobile platform featuring two micro metal gearmotors, five reflectance sensors, an 8×2 character LCD, a buzzer, and three user pushbuttons, all connected to a C-programmable ATmega328 microcontroller.

Pololu 3pi robot Pololu 3pi robot, top view Top view of the Pololu 3pi robot without batteries or LCD. Pololu 3pi robot, bottom view. Pololu 3pi robot, bottom view. Pololu 3pi robot on a 3/4" black line Pololu 3pi robot. Pololu 3pi robot on a 3/4" black line. Pololu 3pi robots Specific features of the Pololu 3pi robot, top view. Labeled bottom view of the Pololu 3pi robot. General features of the Pololu 3pi robot, top view. A 3pi robot following a line in the dark, making the glow of the LEDs more apparent Pololu 3pi robot simplified schematic diagram.
Pololu 3pi robot

Capable of speeds exceeding 3 feet per second, 3pi is a great first robot for ambitious beginners and a perfect second robot for those looking to move up from non-programmable or slower beginner robots.

The 3pi robot is designed to excel in line-following and maze-solving competitions. It has a small size (9.5 cm/3.7" diameter, 83 g/2.9 oz without batteries) and takes just four AAA cells (not included), while a unique power system runs the motors at a constant 9.25 V independent of the battery charge level. The regulated voltage allows the 3pi to reach speeds up to 100 cm/second while making precise turns and spins that don’t vary with the battery voltage.

The 3pi robot makes a great platform for people with C programming experience to learn robotics, and it is a fun environment for ambitious beginners to learn C programming. At its heart is an Atmel ATmega168 microcontroller running at 20 MHz with 16KB of flash program memory and 1KB data memory, enough space to run complicated programs. An extra 512 bytes of persistent flash memory is provided on the microcontroller for data logging or long-term learning applications. The popular, free GNU C/C++ compiler works perfectly with the 3pi, Atmel’s AVR Studio provides a comfortable development environment, and an extensive set of libraries provided by Pololu makes it a breeze to interface with all of the integrated hardware. The 3pi is also compatible with the popular Arduino development platform. We provide a number of sample programs to show how to use the various 3pi components, as well as how to perform more complex behaviors such as line following and maze solving.

Required Accessories

An external AVR ISP programmer such as the Orangutan USB programmer is required to program the 3pi.

The 3pi is powered by 4 AAA batteries, which are not included. We recommend rechargeable NiMH cells, which may be purchased here

Optional Accessories

One expansion kit features cutouts that let you view the LCD below and allow you to reach the power button, reset button, and ISP programming header on the base. The other expansion kit has no cutouts and instead replaces the LCD, giving you access to more I/O lines and more prototyping space. These kits can be purchased with PCBs that have either black or red solder masks; the pictures below show the black versions.

Pololu 3pi Expansion Board Pololu 3pi Expansion Board with cut outs


The following pictures show the 3pi’s LEDs as it drives around in the dark:

Pololu 3pi LEDs Pololu 3pi LEDs in the dark


  • Size: 3.7" diameter

General specifications

  • Processor: ATmega168
  • Motor driver: TB6612FNG
  • Motor channels: 2
  • User I/O lines: 2 (1*)
  • Minimum operating voltage: 3 V (2*)
  • Maximum operating voltage: 7 V (2*)
  • Maximum PWM frequency: 80 kHz
  • Reverse voltage protection?: Y
  • External programmer required?: Y



1* - Digital I/O lines PD0 and PD1 are available; two more analog inputs and one analog/digital pin can be made available by removing jumpers and disabling special features of the board.
2* - Designed for use with 4 x AAA NiMH or Alkaline cells. A step-up regulator boosts the motor voltage to 9.25 V.

Starting with serial number 0J5840, 3pi robots are shipping with the newer ATmega328P microcontroller instead of the ATmega168. The ATmega328 is essentially a drop-in replacement for the ATmega168 with twice the memory (32 KB flash, 2 KB RAM, and 1 KB of EEPROM), so the 3pi code written for the ATmega168 should work with minimal modification on the ATmega328 (the Pololu AVR Library now supports the ATmega328P).

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