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

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

This programmable module combines with a Raspberry Pi to serve as the control center of a small robot or electronics project. Its Atmel ATmega32U4 microcontroller comes preloaded with an Arduino-compatible bootloader, and the board includes dual motor drivers that can deliver 1.8 A per channel to two brushed DC motors. An efficient voltage regulator and level shifters enable it to power and communicate with a Raspberry Pi. This version (item #3117) is assembled with selected through-hole connectors and components installed for use as a Raspberry Pi add-on.

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+, and Pi 2 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 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).

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.

The robot controller is available in two configurations:

• With surface mount components only (no through-hole components or mounting hardware)
• Assembled with selected through-hole components for use as a Raspberry Pi add-on (Raspberry Pi mounting hardware included)

Details for item #3117

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

This version of the A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge is assembled with selected through-hole connectors and components for use as a Raspberry Pi expansion board, as shown in the picture above. A 2×20-pin 0.1″ female header is preinstalled to serve as a Raspberry Pi GPIO connector, and a 6-pin strip of terminal blocks and a DC power jack are mounted for motor and power connections. Abuzzer is also installed, along with two 2×1-pin male headers and shorting blocks for the buzzer and battery level jumpers.

This version ships with a set of four M2.5 standoffs (11 mm length), screws, and nuts that can be used to secure the board to the Raspberry Pi at the proper height for the GPIO connector.

For a version with SMT components only, making it more suitable for standalone use and allowing customization of through-hole components, see item #3116.

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:
  • Can be powered from USB or from a 2.7 V to 11 V external source (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

Driving motors with an A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge on a Raspberry Pi Model B+.

Arduino compatibility

Like our other A-Star 32U4 programmable controllers, the A-Star 32U4 Robot Controller ships with a preloaded Arduino-compatible bootloader (which uses 4 KB of flash memory, leaving 28 KB available for the user program). We provide a software add-on that enables the board to be easily programmed from the Arduino environment and an Arduino library to make it easy to use the additional on-board hardware.

The A-Star 32U4 Robot Controller has the same microcontroller as the Arduino Leonardo and Arduino Micro, and it runs at the same frequency, so most code examples intended for those boards should also work on the A-Star.