I am particularly interested in robotics and control, hence the GUI, RS232 umbilical and automatic depth control.
Initially I had hoped to have an un-tethered ROV. I tried to transmit data using Bluetooth from a laptop to the ROV but as soon as it went under the surface all communication stopped. I also tried data communication using two radio transceivers operating at 438Mhz but got the same result.
So..... back to the tethered approach using an ethernet cable consisting of 4 pairs which makes it easy for the camera as wireless cameras don't transmit underwater either, (I tried that as well). I may experiment in the future with a surface buoy with a wireless camera and data transceiver aerial which will allow semi un-tethered control. Perhaps having a cable direct to the surface will be less restrictive on the ROV's underwater movement control than having a 'semi rigid' control cable following behind to a PC / laptop.
The ROV submerging technique was originally using part of a bicycle inner tube and a car windscreen washer pump. However this method was very slow to respond and difficult to control and ended up either dropping the ROV like a stone to the bottom or rising to the top. Probably a little worrying having water pumped into the same chamber as the electronics but I tried to make it as reliable as possible and with this in mind I incorporated a leak detection unit which alarms on the GUI and automatically surfaces the ROV. I gave up on this submerging method when pumping water inside caused excessive internal pressure and blew off the end cap on the ROV.
My modified ROV includes all learning points, the main one being to use a thruster to submerge the ROV. This photo is the nearly finished design, (I will be continually improving it). Several photos on this site show the ROV in various states of development, some didn't work as well as I had hoped. All the learning points gained are listed on the last page of this site.
New improved ROV is under construction. 4 vectored thrusters controlled via joystick, camera tilt control, battery voltages, compass etc on new GUI.
Please feel free to email me if you would like any further information or explanation.