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.
The diagrams below highlight the important features of the 3pi. Click on either picture for an expanded view.
For instructions on setting up and programming the 3pi, including sample code, contest ideas, and more, see the 3pi User’s Guide.
The 3pi is powered by 4 AAA batteries, which are not included. We recommend rechargeable NiMH cells, which may be purchased from Pololu or at a local store carrying electronics. (We also carry a battery charger that works well with these NiMH cells and can be used to charge the batteries while they are still in the robot.)
3pi Robot Video Gallery
The following videos from Pololu and our customers show some of the things you can do with the 3pi robot. The first video in the playlist introduces the 3pi’s basic features and operation.
The second video shows a 3pi prototype autonomously solving a line maze, first by exploring the maze and then by running the learned shortest path from start to finish, and the third video shows six 3pi prototypes simultaneously participating in a line-following exhibition at a local robotics competition (last one remaining on the line wins!). Please note the 3pis in the last few videos are using additional hardware for things like RC control and obstacle detection.
The above videos (with descriptions) and more can be found on our 3pi videos page. These videos show many more things that you can do with the 3pi, including RC control, following a laser pointer, wall following, solving looped mazes, and driving around line courses with kinks, gaps, and obstacles. Check out what some of our customers have done with this amazing little robot and get inspired!
Note: The 3pi robot currently ships with an LCD with a black bezel as shown in the main product picture, not the silver-bezeled LCD shown in some of the product photos and videos.