Can Mycodo be operated offline?

Hi there,

I installed Mycodo on a Raspi 4. It shows me analog voltages from a sensor collected via a Waveshare AD/DA 1256 board on a dashboard. This works well as long as in the house where Wi-Fi is available. If I take it to the garden, Wi-Fi signal is lost and the browser Chromium) tells me „ERR_INTERNET_DISCONNECTED“.

Is there a configuration possible that allows an operation of the system without internet connection?

As far as I understood the manual Mycodo uses a local host and does not need a connection for operation?

Any idea?

Thanks to all reading this question.

Best regards,

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You will face two issues without a network (and internet):

  1. The Pi will not be able to set its clock to the proper time. Since the Pi does not have a real tie clock, it will not be able to restore the time after a reboot and thus will not be able to record the correct timestamp for measurements and there may be SSL certificate errors as a result of the wrong time. You may not notice issues at first, but there exists a chance that the time gets reset to a period that it has already recorded measurements to, causing a reading of measurements that were previously recorded in the past but are now being re-read as the present due to the time being incorrect. This can be disastrous if your measurements are being used for any crucial system, like growing plants or keeping animals alive. If it is, do not ever let the Pi use the wrong time.

  2. You cannot connect to it. This should be obvious, if there is no network, you cannot connect to it.

You can solve this by:

  1. Add a Real Time Clock.

  2. Make the Pi broadcast a WiFi hotspot that you can connect to, allowing it to host its own network. RaspAP is a beginner-friendly system to enable an access point, but you might experience port conflicts when you install Mycodo (port 80, HTTP), so make sure you set the RaspAP port to something different. There are also more basic configurations (you won’t use 95% of what RaspAP offers), such as wifi-ap.

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@KyleGabriel can you help walk me through this? What exactly is going on when the pi hosts it’s own network? Is this to satisfy Mycodo’s connectivity requirements? I like Mycodo, but I want to control a fruiting room that has no wifi…

@ManBearElk mycodo will work on it’s own, as long as you follow Kyle’s advice of adding a RealTime-Clock so it has a consistant timings without the need to connect to NTP-Servers.

you will then only need to connect to mycodo for maintenance reasons.
for that you could use a raspberry with a display attached, or you connect to the AP of the raspi. or you connect that raspi to a wifi-AP, meshed all the way to your house, like i would suggest (unifi for example has a wide range of APs)


What happens when mycodo loses it’s internet connection? On a side note, I am using the Kasa wifi power strips as outputs to turn on/off a heater, humidifier, and exhaust fan. I know that when the power strip loses it’s connection, I can’t control the outlets. Is there a way around that? Do I need to switch to relays? I have chosen to add a mesh of wireless APs to get me to my fruiting room, but I want to be prepared in case I lose connection to the pi.
Thanks again for your collective efforts. I’m now a patron!

well mycodo needs a way to speak to the kasa strips, or not ?! if this is over wifi, wifi needs to work :smiley:
relays directly connected to the mycodo-pi would work without wifi.

but since this is basic knowledge for this kind of application (and tinkering with it), i guess you will stumble upon many other problems down the way :confused:

You can set up a local network, either via wifi or ethernet, to a wifi router that would allow communication to wifi outlets or power strips.

For any critical application, I always use wired relays. There are far to many points of failure for wireless communication.

If there is no real time clock and no internet, a reboot can cause the clock to reset to an incorrect time. If this is a future time, then only timers will be negatively affected. If this jumps to a past time, where measurements already exist in the database, this can cause a huge number of issues, as functions will be potentially pulling measurements that should be current, but are in fact old measurements.

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