Homebuilt ROVs Forum

I've been trying to design a manipulator for my project, but cannot figure out how to control closing the gripper. I originally planned to use a standard DC motor and some worm gears.

What would happen if I inadvertently tried to over-rotate the gripper mechanism once it was fully open or closed? If the gears were strong enough to sustain the force would the motor burn up applying a constant load without the shaft spinning?

I will have kids using the ROV consistently and am worried that the gripper could be damaged. I looked into servos, but do not want to use a computer for control. Is there anyway to control servos without a computer? Ideally I'd want to use a joystick for arm movement and buttons for open and closed.

You can measure current that flows throu DC motor. If it grab object to much, current rise. So you can use two buttons to close and to open gripper. I think that without any logic, you can not control underwater gripper. If the gripper is on shore, you can use end-switches and some relays.

With Arduino that will be simpl project. You must measure voltage drop on resistor (shunt, I think that every resistor from 10E to 15E will do as long it has 10W or more), and uC can calculate the current with ohm law.

Regards,
fluffy