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Forum Index : Microcontroller and PC projects : Odd RPi PICO Watering controller problem

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MrDomingo
Newbie

Joined: 20/02/2024
Location: Australia
Posts: 5
Posted: 08:46am 15 Sep 2025
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I built two Watering Controllers last year and used one of them last summer. With spring in the air I checked if it was working and found that its web server was inaccessible.  I checked it and the RPi was blinking as usual but the PCB Status led was off.  I extracted the PCB and connecting via USB showed that I could access the WebMite console.  All internal files were in place and I extracted them and compared them to spare RPi Watering controller and all checked out OK. Only difference was in the content of configuration file.  I deployed spare RPi Watering controller and I am curious about how reliable is the WiFi module used on RPi Pico?   I can only imagine that it may have failed.  Note that RPi Controller in question has occasionally gone off-line last summer and I had to power cycle it to restore operation so, it may be that it was unreliable to start with.

As I was about to post this, I re-connected the faulty RPi Controller and it came up good! When not working, the PCB status stays off. What caused that?
 
Geoffg

Guru

Joined: 06/06/2011
Location: Australia
Posts: 3303
Posted: 12:00pm 15 Sep 2025
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I'm not sure of the cause of your particular problem however I have had similar issues in the past.  It seems that the root cause was not the hardware but the TCP/IP protocol stack used in the MMBasic firmware.  MMBasic V6.00.01 and later uses a different protocol stack and that has made a world of difference.  I have a system based on V6.00.01 that has been running for six months and it has been rock solid.

I have updated the Watering Controller BASIC program to V1.5 and this is much more resilient to Internet and TCP/IP issues and it is worth upgrading to this along with the latest version of MMBasic.  V1.5 will automatically upgrade your configuration file and can be downloaded from https://geoffg.net/retic.html (scroll to the bottom of the page).

Geoff
Geoff Graham - http://geoffg.net
 
MrDomingo
Newbie

Joined: 20/02/2024
Location: Australia
Posts: 5
Posted: 12:38pm 15 Sep 2025
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Geoff,
Thank you for that advice.  I did notice that there have been updates but did not want to jump without some guidance.  I will upgrade the 'flaky' controller as soon as possible and see what it gets me.  It's still possible that this particular RPi Pico may have some hardware issue.   BTW, my intent was to use both controllers eventually for our garden as 8 valves are not quite adequate.  Also, I would like to add some LED displays to actually see activity when watering cycle is in progress.  Another concern I have about design is that should it lock-up, I suspect that it will leave some valve running until someone intervenes.

Ned
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2711
Posted: 01:47pm 15 Sep 2025
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  Quote   should it lock-up, I suspect that it will leave some valve running until someone intervenes.
A possible solution is a master relay in the supply to all valves which is controlled by a NE555 timer wired as a 1 shot.

Add code to the Watering Controller to send a pulse, via a capacitor, to reset the 555 at the start of the main loop. If the Pico locks up the 555 will soon timeout shutting off all valves.

The reason for coupling via a capacitor is to ensure that even if the Pico locks up while delivering the reset pulse the 555 will still timeout.
 
Geoffg

Guru

Joined: 06/06/2011
Location: Australia
Posts: 3303
Posted: 03:30pm 15 Sep 2025
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The BASIC program uses the watchdog feature so MMBasic will automatically reboot if the program becomes unresponsive (ie "locks up") and the reboot will automatically turn off all the solenoids including the master.  If the controller does hang it will be in the startup before any valves have been opened.

All the issues (in V5 of MMBasic) caused a reboot, which was a pain but never left a solenoid on.  So, I would not worry about the controller digging a hole in your garden.

Geoff
Geoff Graham - http://geoffg.net
 
MrDomingo
Newbie

Joined: 20/02/2024
Location: Australia
Posts: 5
Posted: 09:40pm 15 Sep 2025
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I was considering adding hardware as per phil99 suggestion and still have a bag of components to do just that but it being already taken care of is good news.

Ned
 
MrDomingo
Newbie

Joined: 20/02/2024
Location: Australia
Posts: 5
Posted: 09:58pm 15 Sep 2025
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Actually, I still have the issue of one controller not communicating even after several power cycles but that may be a hardware issue that may require replacing it. Watchdog feature won't fix that, whether internal to controller or external.  As I type this, my laptop has been on for about 30 minutes and flaky RPi Pico is accessible via IP.  I suspect its some solder joint on the RPi Pico that is a problem.

Ned
 
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