I am trying to think of ways to measure the distance an objects is from an ROV. My end goal is to have a bunch of distance sensors around the ROV to help with object avoidance and maneuvering. I was hoping for each sensor to cost less than 40$ and able to measure up to 10ft. The resolution is less important, but an inch of resolution would be ideal.
Well one thing you can do is to use small transducers to ping and range gate on the ping.
You would have to have a detector circuit which could be very simple to make.
What you would need to do, because of the voltage to drive all of them, is maybe make a switching circuit and you rotate between transducer heads. You ping / listen to calculate if an object is within your ten foot standoff distance and act upon that if it is the case. Considering that sound travels on average around 4850 feet per second in saltwater (or a little slower in freshwater), the amount of time is going to be REALLY small. This would give you plenty of time to cycle between all of your sensors. You are looking at a couple of milliseconds per sensor to create your standoff zone.
One of the things you are going to have to do is to seal off the area where the electrical connection is and create a mount for them.
Well that is my initial two cents on the situation.