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 ATmega328P microcontroller running at 20 MHz and featuring 32 KB of flash program memory, 2 KB RAM, and 1 KB of persistent EEPROM memory. The popular, free GNU C/C++ compiler works perfectly with the 3pi, Atmel 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.
- An external AVR ISP programmer is required to program the 3pi
- The 3pi is powered by 4 AAA batteries, which are not included. We recommend rechargeable NiMH cells.
We currently offer three expansion kits for the 3pi that give you room to augment your 3pi with your own custom electronics. Two are basic kits that simply give your 3pi a second level (with prototyping space and key electrical connections to the 3pi base) to which you can add your own electronics. These basic expansion kits are available with black or red solder masks and with or without cutouts. The version with cutouts (MCM Part# 28-17629
) lets you view the LCD below and allows you to reach the power button, reset button, and ISP programming header on the base. The version without cutouts (MCM Part# 28-17631
) is a full circle that replaces the LCD, giving you access to more I/O lines and more prototyping space. The pictures below show the black versions of these two basic expansion kits.
The third option, the m3pi expansion kit (MCM Part# 28-17628
), makes it easy to significantly upgrade the capabilities of your 3pi by converting it into an m3pi robot (MCM Part# 28-17627
). This expansion board enables the use of ARM's powerful 32-bit mbed development board as the robot's high-level controller (mbed has an m3pi library that makes this easy), which offers significantly more processing power and free I/O lines than the 3pi's built-in 8-bit AVR microcontroller. There are also sockets for Wixel (MCM Part# 28-17702
and XBee wireless serial modules, prototyping space for additional sensors and electronics, eight more user-controllable LEDs, and more. If you already have a 3pi robot, you can use the m3pi expansion kit to upgrade it to an m3pi robot. Otherwise, you can get the m3pi robot directly, which includes a 3pi robot connected to a fully-assembled m3pi expansion board (no soldering is required).