Description
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 AVR microcontroller. 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.
Overview
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.
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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 ATmega328P AVR microcontroller from Microchip (formerly Atmel) 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.
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For instructions on setting up and programming the 3pi, including sample code, contest ideas, and more, see the 3pi User’s Guide.
Required Accessories
An external AVR ISP programmer, such as our USB AVR programmer v2.1 is required to program the 3pi.
The 3pi is powered by 4 AAA batteries, which are not included.
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!
Dimensions
| Size: | 3.7" diameter |
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General specifications
| Processor: | ATmega328P |
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| Motor driver: | TB6612FNG |
| Motor channels: | 2 |
| User I/O lines: | 21 |
| Minimum operating voltage: | 3 V2 |
| Maximum operating voltage: | 7 V2 |
| Maximum PWM frequency: | 80 kHz |
| Reverse voltage protection?: | Y |
| External programmer required?: | Y |
Notes
- 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.
Resources
- Pololu 3pi Robot User’s Guide (Printable PDF)
- Pololu AVR Programming Quick Start Guide (Printable PDF)
- Pololu AVR C/C++ Library User’s Guide (Printable PDF)
- Pololu AVR Library Command Reference (Printable PDF)
- Building Line Following and Line Maze Courses (Printable PDF)
- Programming Orangutans and the 3pi Robot from AVR Studio 4
- Programming Orangutans and the 3pi Robot from the Arduino Environment (Printable PDF)
- Sample Project: 3pi Wall Follower (Printable PDF)
- Sample Project: RC 3pi (Printable PDF)
- Application Note: Using the Motor Driver on the 3pi Robot and Orangutan Robot Controllers (Printable PDF)
- 3pi Robot Videos
- 3pi quick-start sheet and schematic
- Pololu 3pi Forum Section