My rPi gateway suddenly stopped working, no idea what else to try...

[skywatch]

@frapell If you can, get some small coax cable for wifi use and use that instead of the track on the PCB- Make sure it is grounded at the sending end - As for the power, I strongly suggest making a 5v to 3.3V regulator as the pi 3.3v can be quite 'noisey' - a buck regulater will help reduve this a lot. Don't forget capacitors on the input and output of the neg board. I did this for my pi set up too as it has the advantage of the radio getting power from the psu and not cia the pi. A linear regulator like the AMS1117 will do the trick.

[frapell]

@ejlane Well, I am a software developer myself (Not engineer, and certainly not RF engineer) And by looking at my design it is clear that I can barely consider myself an electronic hobbyist :sweat_smile:

Thanks a lot for your suggestions, This is a very basic one-sided PCB I designed in order to avoid having wires, which I thought was worse... I will redesign the whole thing and will post back (If you have more suggestions, I will be more than pleased to know)

@skywatch I am trying to make this as simple as possible, and to be able to fit inside a rPi case, so I will try to get the trace as short as possible between the module and the SMA for now, and see how it goes. As per your AMS1117 suggestion, I am assuming you mean instead of getting 3.3v pin from the GPIO, use the 5V one and go through an AMS1117 to get 3.3v, right? Also, about the capacitor, may I ask what exactly is the "neg board" ?

[skywatch]

@frapell neg board should have been reg board (as in the regulator to go from 5 to 3.3V - When I did this a lot of issues I had went away. Take the 5V supply from the power supply input to the raspberry pi board. This means any current surge will be provided by the power supply and not from the pi itselff. I hope that makes sense.

[frapell]

@skywatch Ahhh, makes sense now :) thanks!

@ejlane I got the specifications from the PCB manufacturer (Attaching below), and the copper thickness is 35 microns...
I managed to get the module with the antenna pin right next to the connector, so the trace length would be just 4mm, for what I was able to find, my case for a single sided PCB would be a "Coplanar wave guide" and plugging all of those values in a calculator I found in KiCAD, it seems that I am fine with a 1 mm wide trace, with a 0.25mm gap with the GND around it.

Hope I got it right! Thank you for your suggestions!

[ejlane]

I think your numbers look good. Nice job getting the trace much shorter - that should help a bunch.

[ejlane]

Oh, and Skywatch's tips are also good. Solid power is very important. I would put a few different capacitors as close to the power pin of the radio module as possible. 100n, and then a selection from: 1u, 4.7u, and 10u. I would likely go with 2 of those microfarad capacitors, and maybe all three. I like to err on the side of overkill where power capacitors are involved.

[frapell]

@ejlane @Yveaux @skywatch So, I have found exactly what was going on, and had nothing to do with the hardware... Basically, one of my nodes was jamming the radio channel :face_with_rolling_eyes:

How I discovered the issue:
There are 2 more flags, besides MY_DEBUG which are MY_DEBUG_VERBOSE_RFM69 and MY_DEBUG_VERBOSE_TRANSPORT_HAL which I couldn't find a way to add, so I did it by editing the configure script and where it says

if [[ ${debug} == "enable" ]]; then
    CPPFLAGS="-DMY_DEBUG $CPPFLAGS"
fi

I changed it for

if [[ ${debug} == "enable" ]]; then
    CPPFLAGS="-DMY_DEBUG -DMY_DEBUG_VERBOSE_RFM69 -DMY_DEBUG_VERBOSE_TRANSPORT_HAL $CPPFLAGS"
fi

Then re-ran the script and recompiled the mysgw binary. The important flag in my case was MY_DEBUG_VERBOSE_RFM69.

When mysgw was running, and everything was working fine, I was seeing lines with DEBUG RFM69:CSMA:RSSI=-102 popping in once or twice (with different values for RSSI) and everything continued normally. Then, when the whole thing was wedged and nothing worked, I noticed that message pretty much going on forever

Sep 09 18:37:11 DEBUG RFM69:CSMA:RSSI=-52
Sep 09 18:37:11 DEBUG RFM69:CSMA:RSSI=-52
Sep 09 18:37:11 DEBUG RFM69:CSMA:RSSI=-53
Sep 09 18:37:11 DEBUG RFM69:CSMA:RSSI=-52
Sep 09 18:37:11 DEBUG RFM69:CSMA:RSSI=-52
Sep 09 18:37:11 DEBUG RFM69:CSMA:RSSI=-53

And on and on and on.... forever... Clearly there was a loop somewhere for whatever reason printing this message. As it turns out, there's a function that the RFM69 driver calls before sending a message https://github.com/mysensors/MySensors/blob/2e00bf6a10f76d6aaa1999e12313237bc3edabd3/hal/transport/RFM69/driver/new/RFM69_new.cpp#L369-L375 that pretty much checks if there is noise in the RF channel, before actually sending anything...
I was doing some modifications to one node I have, where I replaced the arduino with another one, which I thought was a 3.3v one, burned it as so, but it was a 5v. For whatever reason (maybe the different clock speed? dunno...) when doing that, the node will send garbage through the radio... I have no idea how it manages to init the radio... doesn't really matter, the thing was sending something in the same channel constantly...

And that is why the gateway was receiving data from other nodes, but was never able to send back... this other node was preventing it because it would never shut up... I have now replaced the arduino with a 3.3v one, checked in the serial monitor after burning :wink: and re-installed, and everything is back to normal and working...

Thank you all for your help and suggestions, I will nevertheless build the new PCB with the suggested changes and replace the ones I am currently using.

[mfalkvidd]

Great work everyone! I have been following this thread and it makes me very happy to see how you work together.

For the debug flags, check out the ”Advanced” section at https://www.mysensors.org/build/raspberry#advanced

[frapell]

@mfalkvidd Totally missed that! sweet !

[ejlane]

mfalkvidd gave you a great link, but if you ever need to see any possible choices, you can run

./configure --help

and it will show you. The extra flags section is one thing (of many) that it says.

Actually, this is very timely for me, as I'm trying to troubleshoot my own radio issues, so I'll use those extra two flags that you mentioned and see what they say.

Thank you!