Koi is our previous ROV for piloted missions. She first competed in the 2012 MATE competition and has also entered competitions in 2013, 2014, and 2015.
She has two electronics enclosures, one front and one back. The front contains an onboard Windows PC, an Arduino Mega Mini microcontroller, a webcam, a pressure sensor, and an IMU to monitor acceleration and heading. The rear contains power converters, speed controllers for the claw, a second webcam, and an Arduino Mega microcontroller.
The front microcontroller takes in data from the pressure sensor and IMU and controls the servo on the front camera. The rear microcontroller controls the thrusters and claw. Each thruster is connected to a custom enclosure wired by the team that contains a speed controller and power converter. This way, each thruster is modular and can be mounted and demounted independently.
To control the robot, the pilot connects an Ethernet line on the surface end of the tether to their laptop, sends a wakeonlan signal to the onboard PC to turn it on, then connects to it using Remote Desktop Connection. From there, they activate a custom program on the robot that allows them to view camera feeds and sensor data and pass down the control signal from an Xbox controller. The tether also contains lines for 48V power supply from the surface (with a 20A fuse at top) and a second Ethernet line carrying up to four analog video signals.