Homebuilt ROVs Forum

Howdie,

Now my ESC have arrived and i am planning to purchase an IP webcam. I start to wonder how I am going to start it all when it is inside a closed ROV.

The plan:
- Reed switch which will power the Arduino with the network shield.
- Connected to the Arduino a I2C or whatever bus driven relay board to allow me to switch on 4 other devices. Currently 3 ESC and 1 IP Webcam.
- Each ESC will have its own Lipo. And one lipo is shared between the Arduino and the IP Webcam.
- Arduino can be powered directly from the lipo, the IP Webcam will use a DC/DC converter.
- After the Arduino is powered on the landside laptop can connect and send the command to arm the ESC one by one, preventing huge AMPS. And the same goes for the Cam.

A big question remains for me, anybody knows a good board which is capable of switching different voltages 3x5v (ESC) and 1x12V (Webcam) and not using four separate ports for this. All boards I have seen so far need four imputs to switch on or off and I am not sure that the can handle different voltages on the switched side (could be my lack of understanding).

Thanks for you thoughts.

Most relay boards can handle a fairly wide range of voltages. It all depends on the relay, the ones on the board I picked up can handle up to 30V DC or 250V AC both at 10A. Either far exceed anything I can see myself asking of them. In total it has 8 relays and as such will require 8 inputs. I am however planning on using another board to control those pins over I2C so it will effectively only take two data lines plus ground and power.

There are relay boards you can buy that have built in I2C but all of the ones I have looked at are stupid expensive. The relay board I went with was like $11, the boards with the built in I2C were somewhere around $80. From everything I could tell the only real difference was that they had the I2C baked in. So between the Relay board itself and the I2C board (that is also going to be handling a few other tasks) I only ended up spending around $25 and with all I'm currently asking of it will still have 7 open lines. At least that is the plan If that doesn't work out I still really haven't touched any of my GPIO pins so I can easily spare 8 to run the relay board directly.

The other alternative is putting together your own relay/power board. Originally I was going to go with some opto-isolated power MOSFETs and an ATmega or ATtiny (or two) to handle the I2C. They really aren't that complicated but for $11 with opto-isolation and a board I already had I couldn't say no

Hi Zaibach,

Thanks for the input, will start hunting Ebay and the chinees manufactures again. So I will put it down to my misunderstanding the boads so far

Regards