Sonar/IR distance sensor on Navio+


I’m building a rover using raspi B+, Navio+ and APM software. Right now, I’ve all the pieces working, except one: the distance sensor.

I guess that one of the ADC channels in the bottom of the board can be used for this (as APM board also use analog ports for this feature), but not sure if this is true and how to map this ADC channels on Navio+ and APM software…

Any idea about this?



We have not tested the distance sensor yet. Those two spare channels on the bottom of the board are already implemented in APM and we will do a short setup guide in the next few days. You will be the first to test the sonar :smile:


My guess that the only thing you need to do to get a sonar running is setting RNGFND_PIN to 4 or 5 (these are the channels that are not currently used by any sensors.) and setting RNGFND_TYPE to 1 (the analog type). The spare pads are marked ADC2 and ADC3 on the Navio+ board. You could hook up a sonar there.

I would also like to use an analog rangefinder on my Navio+. So the ADC2 and ADC3 can be used by setting RNGFND_PIN to 4 or 5 respectively? Would these pads also work for reading RSSI using 0-3.3v? What about an airspeed sensor?

Hi, I’ve just got my board through and I’m in the process of setting it up from an APM2.5 set up, is it as simple as what @george.staroselskiy says?
Thanks, Ollie

Yes, there are two contacts on the bottom of the NAVIO+ board that are on pins 4 and 5. In this picture they are labeled ADC2 and ADC3. I was able to use them for analogue RSSI and a range finder.

@slackr31337 thanks! Excuse my ignorance but what is analogue RSSI? O

RSSI is receive signal strength indicator. Some radio receivers will output voltage on a pin to indicate how strong of a radio signal it is receiving. 0 volts is 0% and 3.3 or 5 volts is 100% signal.

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Are there any obstacle avoidance programs that could run on the pi too or on a separate controller interfacing with it?

Maybe opencv or simplecv

Maybe like this. Using a Rpi–-how-implement-obstacle-avoidance-single-camera

(PDF) This one uses a px4 and opencv.

Has anyone tried something like this with a navio?

Btw, Pixhawk running AC3.2 or higher - work with Maxbotix MB1242 ultrasonic rangefinder sensor. The sensor connected via I2C. It might be interesting at Navio+ also.

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I want to use L9R receivers which do not have telemetry.
Nevertheless, they have a RSSI output.
Does this mean, I just have to connect the ground of the RSSI output to the GND socket on the picture and the signal of the RSSI output to one of these ADC2/3 pins?