I've worked with a few different GPS modules. Most of them seem to just pump out data and not really interact with the micro controller.

I have a quadcopter (Cheerson CX 20 Big Sky) It has a gps break out board that looks similar to the one I've worked with before. Is it likely that I connect another micro controller to this board? I want to add a cellular module to my quad.

I know that the answer may be "it depends" but before I start testing and researching I just want to know if it's even likely to work.

If the gps is just barfing out coordinates and not interacting with the main board I think it could work. I could just tap in and "listen" -- is this even a possibility?

1 Answer 1


You are quite wrong. The answer is not "it depends", but "yes".

You can have any number of devices listening to (receiving) the transmitted data. You can only have one device sending anything back to whatever it is that is broadcasting the data if you need to configure it in any way. That shouldn't be a problem of course if you have one main controller that does that configuration and everything else is just a passive listener. Just be sure that you don't connect the transmit pins of the passive listeners to anything (unless you want to use them for a completely unrelated purpose to transmit serial data to something else).

The only caveat is that each device you add as a listener will increase the load on the GPS's transmit pin and eventually the slew rate will become too slow and the signal will become distorted. If this ever becomes an issue reducing the baud rate can combat it to a certain extent. For serial though you would need quite a lot of devices for it to become an issue. Two devices certainly won't ever be an issue.

  • Great! Thanks. This is how I thought it might work but I wasn't certain.
    – futurebird
    Mar 18, 2016 at 18:13

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