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.
For instructions on setting up and programming the 3pi, including sample code, contest ideas, and more, see the 3pi User's Guide.
An external AVR ISP programmer, such as our USB AVR programmer is required to program the 3pi.
The 3pi is powered by 4 AAA batteries, which are not included. We recommend rechargeable NiMH cells.
Expansion kits for the 3pi that give you room to augment your 3pi with your own custom electronics are available. A basic kit that simply gives your 3pi a second level (with prototyping space and key electrical connections to the 3pi base) to which you can add your own electronics. The version with cutouts lets you view the LCD below and allows you to reach the power button, reset button, and ISP programming header on the base. The picture below basic expansion kit.
Another option, the m3pi expansion kit, makes it easy to significantly upgrade the capabilities of your 3pi by converting it into an m3pi robot. 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 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.
Since June, 2009 (starting with serial number 0J5840), 3pi robots have been shipping with the newer ATmega328P microcontroller instead of the ATmega168 that was on original units. 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 instead of 16 KB flash, 1 KB RAM, and 512 bytes 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).
(Note that we have no experience with this particular charger and are not specifically endorsing it.) The downside to a charger like this is that you have to remove the batteries from the 3pi to charge them.
The mbed NXP LPC1768 is an easy-to-use MCU development board designed for rapid prototyping.
This device is a programmer for AVR-based controllers, such as the 3pi robot. The programmer emulates an STK500 on a virtual serial port, making it compatible with standard AVR programming software.
Ready to ship prebuilt all-terrain enclosed platform! This is a heavy-duty robotic platform with IG42 078 RPM motors, an enclosed chassis, and RC control system. Powered by DeWalt batteries.
This is powerful wheelchair motor. They make great heavy-duty robot motors. 250W 75RPM motors with 17mm keyed shaft output. They are sold individually and have an electric brake mounted on the back.