PIco & Notehub disconnect

I am using a raspberry pico with the notecard. I am now piloting the setup in a cold environment. I noticed last night that the notecard rebooted more than once. I am guessing that powering the notecard via the pico may not be enough as I have had an issue previously which seem to have been resolved, but maybe not. I am going to look a powering the notecard separately.

However, the disconnect between the pico and the notecard seems to be a valid use case, so I am looking for a solution. I am using the interrupt method for the pico to request new notes from the hub. However, when the notecard disconnects and reboots, the interrupt method no longer works. Is there a suggested method to monitor the connection between the pico and the notecard to ensure they are connected and in sync?

I am using python for this project.

Hi @rksteeves,

On the RPi Pico, the regulator is an RT6150B which is capable of only 800mA, but for the 3V3 pin the datasheet says “it is recommended to keep the load on this pin less than 300mA”. The Notecard needs 2A pulses for GPS and 1A is very common, so unfortunately you can’t reliably power the Notecard via the Pico’s output. However, you can equally well power the Notecard by either connecting the V+ input to the Pico’s VSYS pad, or alternatively connect the VUSB pin to the Pico’s VBUS pad.

If you continue to see issues, make sure you use soldered wires, not header pins/sockets, because header sockets can be limited to 500mA depending upon the quality of your header wires or breadboard.

Thanks for this info Rob. You may recall I had this issue earlier and you made a suggestion that I used and it seem to be working in testing, but in the actual pilot location, I had the results I listed. I have the output from when the board rebooted, is it of any value to look at that to confirm the details of the message on the reboot, or can you safely say that it is just power supply related? Just so you know since yesterday afternoon, the board has not rebooted and it has just gotten colder at the remote location. This morning it was down to just below 2 degree C. I wont be able to retrieve the board until next week at the earliest, but in the meantime, I should have a good deal of data to see if anything else is an issue.

Is there a preference for the 2 solutions you outline below, ie VSYS, or VSUB?

Thanks for all of your help on this and previous issues.


Hi @rksteeves,

Looking back on our previous conversation (thanks for reminding me of that!) it looks like we recommended powering the Notecard/Notecarrier separately. I guess I’m a little confused because you mention “you made a suggestion that I used and it seem to be working in testing, but in the actual pilot location, I had the results I listed”, but in your current solution you are not powering the Notecarrier separately from the Pico?

Also the reboots are almost definitely a low voltage situation (depending on the battery you’re using, cold weather can be a killer to voltage levels as I’m sure you’re aware). I would consult the Pico datasheet but I don’t know that there would be a difference between VSYS or VBUS.


Sorry I didnt mean to mislead you. Yes I did say at the time, I would look into separate power. However, you had also suggested an alternate connection than what I had with the pico using 3.3v and it seemed to have worked during my testing and I completely forgot about powering separately, I will change to the separate power via the pico vusb before proceeding.

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