Description
The Pololu 3pi+ 32U4 robot is a complete, high-performance mobile platform based on the Arduino-compatible ATmega32U4 MCU. Its many features include dual quadrature encoders for closed-loop speed or position control, line sensors, front bump sensors, and a full IMU (3-axis accelerometer, magnetometer, and gyro), all packed into a robot that fits in the palm of your hand.
The 3pi+ 32U4 is a versatile, high-performance, user-programmable robot that measures just 9.7 cm (3.8″) in diameter. At its heart is an ATmega32U4 AVR microcontroller from Microchip (formerly Atmel), and like our A-Star 32U4 programmable controllers, the 3pi+ 32U4 features a USB interface and ships preloaded with an Arduino-compatible bootloader, so all you need to program it is a USB A to Micro-B cable (not included). A software add-on is available that makes it easy to program the robot from the Arduino environment, and we have Arduino libraries and example sketches to help get you started. For advanced users who want to customize or enhance their robots with additional peripherals, the robot’s power rails, power system controls, and microcontroller’s I/O lines can be accessed via several 0.1″-pitch expansion ports.
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The 3pi+ (or 3𝜋+) features two H-bridge motor drivers and a variety of integrated sensors, including a pair of quadrature encoders for closed-loop motor control, a complete inertial measurement unit (3-axis accelerometer, gyro, and magnetometer), five downward-facing reflectance sensors for line-following or edge-detection, and left and right bump sensors along the front face of the robot. Three on-board pushbuttons offer a convenient interface for user input, and an LCD, buzzer, and indicator LEDs allow the robot to provide feedback.
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The robot also features a unique power system that runs the motors at a constant 8 V independent of the battery charge level, so the speed of the motors does not vary with the battery voltage.
The 3pi+ 32U4 robot is available as a kit or fully assembled with three different motor options:
| 3pi+ 32U4 Version | Products | Micro Metal Gearmotor | Top Speed | Comments |
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| Standard Edition | assembled or kit | 30:1 MP 6V | 1.5 m/s | good combination of speed and controllability |
| Turtle Edition | assembled or kit | 75:1 LP 6V | 0.4 m/s | longest battery life, easiest to control, good for swarm robots or introductory robotics courses |
| Hyper Edition | assembled or kit | 15:1 HPCB 6V | ~4 m/s | very fast and difficult to control, easy to damage; only recommended for advanced users |
What else you will need (not included)
- four AAA batteries: the 3pi+ robot works with both alkaline and NiMH batteries, though we recommend rechargeable NiMH cells
- a USB A to Micro-B cable to connect the robot to your computer for programming and debugging
Details for item #3736
This Hyper Edition version is assembled with high-speed 15:1 HPCB 6V Micro Metal Gearmotors. It is very difficult to control and fast enough to damage itself from impacts, so it is only recommended for advanced users. We strongly recommend keeping motor speeds below 50% on this version.
Details for item #3737
This Standard Edition version is assembled with 30:1 MP 6V Micro Metal Gearmotors, which offer a good combination of speed and controllability.
Details for item #3738
This Turtle Edition version is assembled with 75:1 LP 6V Micro Metal Gearmotors, which allow for longer battery life than the other editions. The maximum robot speed is approximately 0.4 m/s, making it well suited for applications where slow, controlled speed is important, such as coordinated swarm robots and introductory robotics courses.
Dimensions
| Size: | 97L × 96W × 36H mm |
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| Weight: | 100 g1 |
- Notes:
1: Of assembled robot without batteries.
Comparison with the original 3pi
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Original Pololu 3pi robot. |
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The 3pi+ 32U4 offers many major improvements over the original 3pi, including:
- ATmega32U4 microcontroller with Arduino-compatible bootloader can be programmed directly through a USB connection
- Quadrature encoders on both motors for closed-loop position and speed control
- Full 9-axis IMU (three-axis gyro, accelerometer, and compass)
- Bottom-loading battery holders keep batteries accessible even if additional levels are added
- Full wrap-around bumper to protect electronics from collisions
- Two bump sensors on the front
The 3pi+ 32U4 uses a different microcontroller with different pin mappings compared to the older 3pi, and some of the software library interfaces are different, so programs written for the original 3pi will not work on the 3pi+ 32U4 without modification.
Resources
- Pololu 3pi+ 32U4 User’s Guide
- Schematic diagram of the 3pi+ 32U4 Control Board
- Pinout and power distribution diagrams of the 3pi+ 32U4 Control Board
- Dimension diagram of the 3pi+ 32U4 Robot
