DC Motor Control in ROV

I can't think of a way to achieve what you want with 2 DPDT switches. The left-right switch would need a center position where both motors are active (assuming you want to go straight ahead, too).

A setup that works but need a bit more thinking of the operator could be made using DPDT switches with a central OFF position:
Use switch 1 to control motor 1 for forward-stop-reverse
Use switch 2 to control motor 2 for forward-stop-reverse

By cleverly combining switch positions you can achieve all possible combinations of motor directions and thsu steer your ROV.

If you need forward-reverse as well as left-right control, you will need a bit of logic to combine the signals from the switches into suitable motor control signals (a "mixer").

by the way: why don't you just use a ready made model RC control? The bettter ones have the mixer included.

 

A simple mixer can be built from 4 relays, 4 pusbuttons and 8 diodes. Each pushbutton in connection with the diodes activates 2 relays. The diodes decouple the pushbuttons from each other such that different combinations of relays are controlled by one pushbutton each. The relays in turn control the motors:


[edit] You have to avoid to push more than one button at a time. Otherwise the relays will short the power supply (battery). A good idea would be to use an electromechanial joystick that allows only horizontal and vertikal movement of the stick. Thus at any time only one button can be activated.

Harald