Pi Hat PCB
The Pi Hat PCB board controls the ROV. It is similar to a drone flight controller but developed specifically for our software stack and marine robotics applications.
The Pi Hat, a custom-designed PCB, interfaces with the Raspberry Pi 4 and acts as the main interface for all the electronics. It connects the Raspberry Pi 4 to a Raspberry Pi Pico using the UART protocol to control our sensors and thrusters via a micro-ROS bridge, providing direct control of the Pico to the ROS network. The Pi Hat also connects to external temperature and depth sensors and a status LED. The Pico sends PWM and Dshot signals to the Lumineer ESCs. Although the Dshot protocol is not fully implemented yet, it would allow us to obtain telemetry data on the thrusters, such as power consumption and RPM. To control the pneumatics, cooling fans, and lights, 12V and 5V transistor switching circuits were included in the design. The Pi Hat has slots for additional breakout boards, such as the BNO085, BME280, and another custom PCB expansion board, because we did not have time to make a second revision with connections for all the extra sensors we needed to add. In the physical stackup, it sits neatly on top of both the Raspberry Pi and the power distribution board, allowing communication between the power board and the Pi Hat using the SMBus protocol.
Current Status
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V1.0tested and functional. Some bugs with the PCA servo driver, but this is only in use for the status LED, as we are using the Pico for all PWM
Sensors and parts
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- This is used to check ambient temperature of the box. It is a good inductor of if the fan is running correctly. The humidity sensor ensures safe operating conditions
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BME280
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Internal Temp sensor on power board
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Leak detection pcb
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Cooling fan
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External Temperature Sensor
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Bar02 Pressure Sensor
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Status LED
(TODO: need to add links and descriptions)
To Do
V2: In design phase
- will carrier an CM4 instead to of using a RPi4 to increase space efficiency and eliminate bloat that is not needed