The Deliverator – Wannabee

So open minded, my thoughts fell out…

Another checkmark for the ROV project

Posted by Deliverator on November 18th, 2005

Met up with Erik today at school and headed over to Larry’s garage (by way of Jack in the Box) to work on the ROV. Larry took the plastic backing off the mini controller board to examine the power regulators for the board. Though the power plug on the housing says +9v, the regulators are of a type that will happily run off higher voltages just fine. We were concerned that we might have to have a bunch of power supplies for the control unit, lights, camera, etc. Larry hooked the controller up to a bench supply just to make sure and the controller ran happily on 12v. He scrounged around on one of his computers and found some code that he had written for it 3-4 years ago, while waiting for the full-size FIRST boards to arrive. Larry hooked up the controller to a neat circuit that simulates PWM input from a radio-interfaced operator interface (Joystick) and the controller with his code responded to it. It is questionable whether we can run PWM over such a long tether wire as will be used, but I think we will give it a try. If not, the control board has a TTL port and we can probably get some TTL->RS485 chips that do differential voltage signalling for longer distances.

After playing around with the controller for a while, we figured out where to mount everything on the “sled.” We will have 2 cameras, 3 motor speed controllers, the controller and a fuse panel. The only fuse panel I had been able to find was total overkill for the job and would not have fit. It had mounts for about a dozen fuses. Rather than scrounge for a smaller panel (Larry though IS might have a 4 fuse unit somewhere in the rat-sized Labyrinth that is the TRC room), Larry solved the problem by cutting the panel in half with the bandsaw! Larry is definitely a master of quasi destructive creation! Perhaps he is the American version of Shiva, ala American Gods. After figuring out where to mount everything, we used the drill press and created some threads and bolted everything in place. We test fit the sled (with all electronics mounted) in the cavity and everything fit, with a planned 1/4″ margin for error. Measure twice, cut once, indeed! There will definitely be quite the rats nest of wires inside once we get everything wired up. Next time, we will have to unmount all the electronics, get the sled welded, drill and tap the holes for the electronic connectors and start wiring everything up. I think this sled idea is really going to work out quite well, as we can remove all the electronics from the cavity by simply pulling off the end cap and disconnecting the tether. Should make things simple to replace if we burn out a fuse or something. Here are some pictures from tonight’s events.