The Pololu Zumo 32U4 robot is a versatile tracked robot based on the Arduino-compatible ATmega32U4 MCU, and this kit contains most of the parts you need to build one—all you need to add are a pair of micro metal gearmotors and four AA batteries .
The Zumo 32U4 is a highly integrated, user-programmable and customisable tracked robot. It measures less than 10 cm on each side and weighs approximately 275 g with batteries (170 g without), so it is both small enough and light enough to qualify for Mini-Sumo competitions, but its versatility makes it capable of much more than just robot sumo battles.
At the heart of the Zumo 32U4 is an Atmel ATmega32U4 AVR microcontroller, and like our A-Star 32U4 programmable controllers, the Zumo 32U4 features a USB interface and ships preloaded with an Arduino-compatible bootloader. 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. A USB A to Micro-B cable (not included) is required for programming. For advanced users who want to customize or enhance their robots with additional peripherals, the robot’s power rails and microcontroller’s I/O lines can be accessed via 0.1″-spaced through-holes along the sides and front of the main board.
The Zumo 32U4 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 downwards-facing reflectance sensors for line-following or edge-detection, and front- and side-facing proximity sensors for obstacle detection and ranging. Three on-board pushbuttons offer a convenient interface for user input, and an LCD, buzzer, and indicator LEDs allow the robot to provide feedback.
The Zumo 32U4 robot is available fully assembled with three different motor options (see the Motors section below for more information on how these different gear ratios perform):
The Zumo 32U4 robot is also available as a kit (without motors) for those who would prefer to assemble it themselves or who want to use different motors than those in the three assembled versions.
This version of the Zumo 32U4 robot (item #3124) is a kit; assembly (including soldering) is required. Motors and batteries are sold separately. A USB A to Micro-B cable (not included) is required for programming.
New blade! As of August 27, 2015, we are shipping these kits with a new blade style (as shown in the kit contents picture below). Unlike the previous blade, which shipped flat, this version has its chassis mounting tabs pre-bent to the appropriate angle. It also features cutouts around the general-purpose mounting holes, allowing them to be bent to different angles if the application calls for it (e.g. to tilt the proximity sensor emitters up or down).
With the exception of motors, batteries, and a USB A to Micro-B cable, this kit contains everything necessary to build and operate a Zumo 32U4 robot:
See the Zumo 32U4 robot user’s guide for detailed assembly instructions.
The Zumo chassis uses two micro metal gearmotors, one for each tread. The ideal motors for your robot depend on your desired torque, speed, and current draw, so motors are not included with the kit version of the chassis (motors are included with the assembled versions of the Zumo 32U4 robot). We generally recommend using high-power (HP or HPCB, which have long-life carbon brushes) versions of our micro metal gearmotors since the tracks require a decent amount of torque to move effectively; higher gear ratios of the non-HP motors might work if you want lower current draw, but they will be slower and offer less control. Specifically, we primarily recommend the 50:1, 75:1, or 100:1 HP (or HPCB) motors for use with this chassis, and these are the versions we include in our assembled Zumo 32U4 robot. Additionally, be sure to get a version with extended motor shafts if you want to be able to use the Zumo 32U4’s encoders.
You can use the following table to compare these three gear ratios in more detail. The first four columns are specifications of the motors themselves, while the last column is the measured top speed of a Zumo chassis loaded to a weight of 500 g and driven with these motors. Note that the specifications are for 6V operation, which is approximately the voltage you would get with four alkaline batteries; four NiMH AA cells will typically provide less than 5V.
Micro Metal Gearmotor |
Free-Run Speed @ 6V |
Stall Torque @ 6V |
Stall Current @ 6V |
Top Zumo Speed @ 6V and 500g |
|
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50:1 HP or 50:1 HPCB | 625 RPM | 15 oz·in | 1600 mA | 40 in/s | (100 cm/s) |
75:1 HP or 75:1 HPCB | 400 RPM | 22 oz·in | 1600 mA | 25 in/s | (65 cm/s) |
100:1 HP or 100:1 HPCB | 320 RPM | 30 oz·in | 1600 mA | 20 in/s | (50 cm/s) |
The Zumo 32U4 robot runs off of four AA batteries. It works with both alkaline and NiMH batteries, though we recommend using rechargeable AA NiMH cells.
Our older Zumo robot for Arduino, built with a Zumo Shield, is another Arduino-compatible robotic platform based on the Zumo chassis. The Zumo Shield mounts to the Zumo chassis and features motor drivers and various sensors, but it does not have an integrated microcontroller; rather, it is designed to interface with boards that have a standard Arduino form factor, like an Arduino Uno, Arduino Leonardo, or A-Star 32U4 Prime, and these boards serve as the main controller for the robot.
By contrast, the Zumo 32U4 includes an on-board ATmega32U4 microcontroller (the same one used in the Leonardo and A-Star 32U4 boards), combining the functions of the Zumo Shield and the separate Arduino controller into a single, compact board that is just as easy to program as a standard Arduino or A-Star thanks to its USB interface and preloaded Arduino-compatible bootloader. The Zumo 32U4 retains all the features of the Zumo shield (e.g. dual motor drivers, inertial sensors, and buzzer) while adding many new features, including dual quadrature encoders, proximity sensors, an LCD, and two extra user pushbuttons.
Some of the pin mappings and software libraries differ between the Zumo 32U4 and Zumo robot for Arduino, so programs written for one robot generally need to be modified to work on the other.
Version: | kit — assembly required, motors not included |
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We have noticed that the accelerometer in the LSM303D is particularly sensitive to brown-out conditions. If power is removed and the voltage on the 3.3 V power supply line falls significantly, but is not allowed to drop completely to 0 V, the accelerometer can be put into a bad state. When power is reapplied to the LSM303D, the accelerometer then returns readings on some or all axes that are large values and do not change much or at all. (We have often seen readings like -32760 and 24539.)
To prevent this problem from occurring, the voltage on the 3.3 V line must be allowed to fall to about 0 V when power is removed from the LSM303D. Depending on other loads and the amount of capacitance on the 3.3 V line, it can take up to several seconds for this to happen, meaning that you should avoid interrupting power to the LSM303D for any shorter period, and if such a short interruption does occur, you should remove power again for a longer period to allow the accelerometer to reset properly.
If the voltage takes too long to fall, you can add a resistor between 3.3 V and ground (a “bleeder resistor”) to discharge the 3.3 V line more quickly when power is removed. We suggest trying a resistor in the 1 kΩ to 10 kΩ range. (Note that a stronger bleeder resistor will cause the voltage to fall more quickly when power is removed, but it will also waste more power when the supply is present.)
The Zumo 32U4 includes a bleeder resistor on the 3.3 V line.