The A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge is a programmable module well-suited for robotics applications, designed to work either as an auxiliary controller mounted to a Raspberry Pi or as a standalone control solution for a small robot. This A-Star (abbreviated A*) is based on Atmel’s ATmega32U4 AVR microcontroller, which has built-in USB functionality, and it ships with a preloaded Arduino-compatible bootloader. Its complement of peripheral hardware includes dual motor drivers capable of delivering a continuous 1.8 A per channel, along with pushbuttons, LEDs, and an optional buzzer for building a user interface. An efficient switching voltage regulator allows the controller to work over a wide range of input voltages (2.7 V to 11 V).
The robot controller board conforms to the Raspberry Pi HAT specification, allowing it to be used as an add-on for a Raspberry Pi with a 40-pin GPIO header (Model B+ or newer, including Pi 3 Model B and Model A+) . On-board level shifters make it easy to set up I²C communication and interface other signals between the two controllers, and the A-Star automatically supplies 5 V power to an attached Raspberry Pi. In this setup, the Raspberry Pi can handle the high-level robot control while relying on the A-Star for low-level tasks like reading analog sensors and controlling timing-sensitive devices (e.g. servos).
We provide a library that helps establish communication between the A-Star and a Raspberry Pi, as well as a tutorial that demonstrates how to use the library and its included example code to build such a robot.
Our comprehensive user’s guide provides the basics you need to get started with the A-Star as well as detailed technical information for advanced users.
This product requires a USB A to Micro-B cable (not included) to connect to a computer.
A-Star 32U4 Robot Controller LV (2.7 V to 11 V) configurations:
- Item #3116: Surface mount components only (no through-hole components or mounting hardware)
- Item #3117: Assembled with selected through-hole components for use as a Raspberry Pi add-on (Raspberry Pi mounting hardware included)
A-Star 32U4 Robot Controller SV (5.5 V to 36 V) configurations:
- Item #3118: Surface mount components only (no through-hole components or mounting hardware)
- Item #3119: Assembled with selected through-hole components for use as a Raspberry Pi add-on (Raspberry Pi mounting hardware included)
- Dimensions: 65 mm × 56 mm (2.6″ × 2.2″)
- Programmable ATmega32U4 MCU with 32 KB flash, 2.5 KB SRAM, 1 KB EEPROM, and native full-speed USB (clocked by precision 16 MHz crystal oscillator)
- Preloaded with Arduino-compatible bootloader (no external programmer required)
- All 26 general-purpose I/O lines from the ATmega32U4 are broken out (including PB0, PD5, and PE2); 7 of these can be used as hardware PWM outputs and 12 of these can be used as analog inputs (some I/O lines are used by on-board hardware)
- Convenient 0.1″-spaced power, ground, and signal connection points
- Dual bidirectional DRV8838 motor drivers (1.8 A per channel)
- Buzzer option for simple sounds and music
- 3 user-controllable LEDs
- 3 user pushbuttons
- Reset button
- Level shifters for interfacing 5 V logic to 3.3 V Raspberry Pi
- Power features:
- 5 V power can be sourced from USB or from a 2.7 V to 11 V external supply through on-board regulator (with several access points for connecting external power)
- Switching 5 V regulator enables efficient operation
- Power switch for external power inputs
- Reverse-voltage protection on external power inputs
- Power selection circuit allows for seamless switching between power sources while providing overcurrent protection, and feedback about which power source is selected
- Provides 5 V power to Raspberry Pi
- 6-pin ISP header for use with an external programmer
- Comprehensive user’s guide