A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge

Description: 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+, Model A+, Pi 2 Model B, or Pi 3 Model B). 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 5V 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.

Features:

• 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