This is more than an instructional is a review of what I learned from this chassis, although it is easy to assemble and there are already control boards, there are experiences that I like to share if you want to make your ROV from scratch, now I leave some comments on My experience was 5 years ago.

Step 1: The Motor Control

My options was:

SN754410 Description

The SN754410 is a quadruple high-current half-H driver designed to provide bidirectional drive currents up to 1 A at voltages from 4.5 V to 36 V. The device is designed to drive inductive loads such as relays, solenoids, DC and bipolar stepping motors, as well as other high-current/high-voltage loads in positive-supply applications.

The L293B and L293E are quad push-pull drivers
capableof deliveringoutputcurrents to 1Aperchannel. Each channelis controlledby a TTL-compatible logic input and each pair of drivers (a full bridge) is equipped with an inhibit input which turns off all four transistors. A separate supply input is provided for the logic so that it may be run off a lower voltage to reduce dissipation.

knowing that they have a strength of 1 amp, I wanted to not stay with that limit, what I thought was to weld one above the other with good results

Step 2: 1rst Test, Going Fordward

Here the test of how it worked, send a fixed signal to the pins of front, back (or making a routine so that they were not active at the same time), calm, the diodes protect the engines well, I understood that there is no need to maintain a fixed signal but you have to insert a pulse and synchronize

Step 3: The Power

I only use a lipo battery, this is good for this type of loads, which in turn now there are more circuits to charge the lipo cells with a simple usb

Step 4: The Mounted Add-ons

In the video I show how it was with a servo motor mounted on the tip of it, I liked how it worked xq was very clean, plus a rf signal to which I will devote a good post

Step 5: The Controller

I made many variations of a control, with 4 buttons with six with d-pad, analogous, the important thing is that we understand that so that we can save on hardware with programming, it is much better, we have to use creativity, and the same energy that we use to create the problems is the same as we will use to solve them

I Used:

https://www.sparkfun.com/products/retired/155

Great Results

https://www.sparkfun.com/products/10535

https://www.sparkfun.com/products/10533

Good results

https://arduino-info.wikispaces.com/Nrf24L01-2.4GH...

good results

Step 6: Explanation (Spanish)

If you speak spanish this is a explanation. if you dont ill soon will upoload a better instructable

Step 7: One Step Higher

This was my last creation with this chassis

in conclusion it is very good equipment, compatible with your ideas, whether you want to make it work with plates that are ready or do something from scratch, I wish you success in the next robotics projects, thanks for reading!