Romi 32U4 Control Board

Description

The Romi 32U4 Control Board turns the Romi chassis into a programmable robot based on the Arduino-compatible ATmega32U4 MCU. Its features include integrated dual motor drivers, a versatile power circuit, and inertial sensors, as well as connections for quadrature encoders and an optional LCD. The board also has the ability to interface with an added Raspberry Pi, making the foundation for a complete Raspberry Pi-controlled Romi robot.

Like the A-Star 32U4 programmable controllers, the Romi 32U4 Control Board is built around a USB-enabled Atmel ATmega32U4 AVR microcontroller, and it ships preloaded with an Arduino-compatible bootloader. The control board features two H-bridge motor drivers and is designed to connect to a Romi Encoder Pair Kit (available separately) to allow closed-loop motor control. It also includes a powerful 5 V switching step-down regulator that can supply up to 2 A continuously, along with a versatile power switching and distribution circuit. A 3-axis accelerometer and gyro enable a Romi 32U4 robot to make inertial measurements, estimate its orientation, and detect external forces. Three on-board pushbuttons offer a convenient interface for user input, while indicator LEDs, a buzzer, and a connector for an optional LCD allow the robot to provide feedback.

The Romi 32U4 Control Board can be used either as a standalone control solution or as a base for a more powerful Raspberry Pi controller. Its on-board connector and mounting holes allow a compatible Raspberry Pi (Model B+ or newer, including Pi 3 Model B and Model A+) to plug directly into the control board. Integrated level shifters make it easy to set up I²C communication and interface other signals between the two controllers, and the control board 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 Romi 32U4 Control Board for low-level tasks, like running motors, reading encoders, and interfacing with other analog or timing-sensitive devices.

The I/O lines of both the ATmega32U4 and the Raspberry Pi are broken out to 0.1″-spaced through-holes along the front and rear of the control board, and the board’s power rails are similarly accessible, enabling sensors and other peripherals to easily be connected.

A software add-on is available that makes it easy to program a Romi 32U4 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.

Features

• Size: 4.4″ × 3.3″ × 0.38″1
• Weight: 35 g (without included hardware)
• Current rating: 5A
  (the rating for the battery power switching circuit and limits the current available at VSW)
• Processor: ATmega32U4 @ 16 MHz
• RAM size: 2560 bytes
• Program memory size: 32 Kbytes
  (Note that 4 KB of the MCU's 32 KB of flash memory is used by the pre-installed USB bootloader.
  All 32 KB is available when programming via the ISP header rather than the bootloader)
• Motor driver: DRV8838
• Motor channels: 2
• Minimum operating voltage: 2.5V
• Maximum operating voltage: 10.8V
• Continuous output current per channel: 1.8A
• Logic voltage: 5V
• Reverse voltage protection: YES
• External programmer required: NO
• Identifying markings
• PCB dev codes: rom04a
• Other PCB markings: 0J10217