ARM/AVR-based rover with video feed, controlled via USB gamepad analog sticks. Raspberry Pi Zero with RedBear IoT pHat (which could be replaced by a Raspberry Pi Zero W) and PiCamera handles wifi, video, and command conversion. ATMega328P connected via UART for DC/servo motor control (PWM outputs) and battery voltage monitor. Camera mounted on micro-servo pan-tilt module for independent look control (+/- 90 degrees vertical and horizontal from straight ahead). Powered by 7 AA NiMH batteries providing ~8.4 volts to DC motors via L293D H-bridge and 5 volts to the rest of the circuit using a LM2575T-5.0 1A switching regulator.

(additional notes are provided in each directory)

Atmel Studio 7 project for ATMega328P motor control code. Converts serial message to motor control values on PWM pins. Also reads battery voltage with ADC pin.

Python application for converting gamepad input to 4 integer values, trasmitted over ZeroMQ REQ/REP socket to Raspberry Pi. Display MPEG feed from Pi Camera and battery voltage from AVR. Allows snapshots and video recording on controller device. OpenCV decoding and processing allow general computer-vision additions before frame is provided to display thread.

1. ZeroMQ<->UART interface, converts 4-integer values to 11-byte UART command w/ CRC, replies with voltage.
2. /dev/video0 (RPi Camera configured with l4v2-ctl) piped to netcat for MPEG video stream.

MotorControl board handles interfacing RPi control of dc and servo motors through AVR via PWM outputs, voltage conversion from battery to 5v, and level shifting between 3.3V and 5V for UART communication between AVR and RPi.

Electrical schematics and pcb layout files made with gEDA. Board ordered from OSH Park.

Version 1 tested and functional, though some holes should be enlarged in version 2 (LM2575, 4-pin terminal block, L293D, 1N5819).

• python3
• pygame
• opencv
• numpy
• ZeroMQ
• avr-libc
• v4l2-utils (for v4l2-ctl)

• For general use, RPi can run on a local network. As long as the controlling computer is on the same network, it's just a matter of connecting to the correct IP. For portability, RPi should be set up as a network access point, and controlling computer should connect to that network. The control program can then connect to the network gateway.

• Since gEDA appears to have a limited user base, future revisions of the MotorControl board will be done in Eagle or KiCad.

• Current version of controller program requires gamepad input to function. Future version to include keyboard control as fallback/secondary input.