RS+ NMEA output to Raspberry Pi

Hello all!

I am working on a robotics project using RS+ for rover with base corrections from another RS+. I am reading NMEA (specifically using $GNRMC sentence) over serial with USB to PC settings for the reach.

I am having intermittent connection issues between the Pi and the Reach. When conditions are cooler, I seem to maintain connection alright. As temps warm up, the ttyACM address of the reach jumps around and does not remain consistent. This happens when reading serial from the Reach.

In cooler temps, I seem to be able to run my setup well enough. I have an Arduino Mega as the only other device attached to the Pi. The Arduino does not experience its’ ttyACM address shifting, it persists regardless of temperatures I’ve been working in.

I believe I read in the Community somewhere that the RS+ will pull around 500Ma. Is there a way to use the USB to PC connection without also drawing charge power?

The reach also will intermittently turn off when connected to the Pi through USB. I’ve checked every time this happens and the Reach is very close to full charge. I’ve checked for shorts or miswiring but I do not appear to have any issues there. This also seems to happen when temperatures are higher.

If there are work arounds or fixes for these issues on USB to PC communication, I’d love to hear those.

I’d also like to pursue reading NMEA over Bluetooth to the Pi but I’ve been unable to find docs or Community posts on this. I found one post about a Pi reading NMEA through BT, but it was not a how to, nor a troubleshoot on this specific issue.

I am able to establish a BT connection between the Reach and the Pi, but the Pi tells me that the device provides no services and shows to not be connected.

Would another better solution be to pursue using Navio/M+ units instead of a full on RS+ on each ground rover? I’d like to use RS+ as we have quite a few of them.

RS+ position streaming USB to PC:
115200 Baud
GNSS at 5Hz with corrections off the base at 1Hz

I’m open to using any of the position streaming methods, I just need something that will hold a consistent connection with the Pi, regardless of operating temps.

The Arduino is communicating at 500k Baud, but again I don’t think this should have much effect on the Reach connection, could be wrong.

I am currently trying a Udev rule renaming the Reach, will update when it gets hot enough to see if I’m having the same issues with turning off/bouncing ACM addresses.

Hi Bryan,

Sorry for the delayed response!

I see that you have several questions. I’d suggest starting with one of them, as others may be its consequence.

Did I get it right that your Reach RS+ sometimes turns off while it’s connected to the Raspberry Pi via USB?

May I ask you to share the Full system report from your device? It will help us check if the unit overheats. The Full system report contains sensitive information. So please send it to me via

Would another better solution be to pursue using Navio/M+ units instead of a full on RS+ on each ground rover?

All calculating and operating processes in Reach RS+ and Reach M+ are the same. The only difference between them is that Reach RS+ has some field-ready benefits: its own battery, mount-thread, IP67 protection.

Using Reach M+ instead of Reach RS+ will lead you to the same results. However, placing the module over the point might be a bit tricky because of external components and the lack of any threads for the pole.

Hi @capStaff,

How is it going? Did you have a chance to get a Full System Report?

I replied to with a full system report today. Still experiencing intermittent shutdowns as well as not being able to power the unit back on without a battery disconnect.

Hi there,

I just want to note that we’ve received the Full System Report from Bryan.

I’ll update this thread with new info as soon as we get it.

Hi there,

As we promised, I’m back with an update: we’ve found the signs of overheating in the logs. It’s tied up in the particular environmental conditions and hardware features of this receiver. At the moment, Bryan’s setup works fine.