More Servos on the ROV


#1

Hey all! I was wondering if there was away to use more servos on the OpenROV boards. I bought the experimental developer kit and will not be using the regular kit. I am not using the servo camera and all that jazz but wanted to use more servos for maybe a gimbaled camera and manipulators. The problem is that I don’t think the board has enough servo channels. Thanks for your help.


#2

Hi:

The 2.8 controller brings wiring for one servo (+5V, GND, PWM) out to the DB-25 connector, and from there out of the endcap, as part of a normal build.

On the controller board itself, there are breakouts for six standard 3-pin servo plugs. Three of these are used by the ESCs, and one for the camera tilt servo, leaving two spare. One of these spare channels is the one brought to the DB-25 connector.

If you need more servo channels, it is easy to get them by just tapping into the uncommitted digital I/O lines that are on the prototyping headers. Servo PWM outputs are nothing more than digital I/O lines that have been linked in software to a timer via the Arduino servo library. You can do this for many of the digital I/O lines on the prototyping headers. The controller board mimics a Arduino Mega board, so you can develop any app you need on an Arduino Mega first, then easily port it to the controller board.

Hope this helps.

-W


#3

Another option would be to add one of these Adafruit PWM boards (https://www.adafruit.com/products/815) to the I2C lines which I believe are available on the DB-25 connector. It might be overkill for what you need though.


#4

Hey! Thanks a lot for the info. Makes much more since now. Cool!


#5

Hey! Thanks for the thought! Will definitely look into that if I need a lot of servos, haha!