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Ideas to connect to devices when wifi unavailable
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Ideas to connect to devices when wifi unavailable

by drbrunner on Wed Jun 02, 2021 9:10 pm

Hi,

I work at a school (teacher of STEM) and have had a successful run teaching IOT using the Adafruit tutorials (e.g. https://learn.adafruit.com/adafruit-io- ... ital-input).

Until now, we have been relying on students and me using hotspots from our phones for wifi connections.

I had always hoped that we might find a way to connect to our school wifi but that has not come to fruition and I am led to believe that this will not be possible.

We have now reached a point where many of our projects are ready to be used full time around the school (think monitoring of fish tanks and insect enclosures, monitoring remaining hand sanitiser and soap in bathrooms, garden moisture sensing and tap control etc).

My question if anyone has a suggestion of the best ways to connect these devices to the internet when there is no wifi available. Should I invest in wifi dongles from the local providers through the school? If so, is there any idea of how many of these devices can connect to the dongles (I probably need between 10-20 connected at any time).

Is there anything else that people might suggest?

drbrunner
 
Posts: 4
Joined: Wed Dec 04, 2019 2:26 am

Re: Ideas to connect to devices when wifi unavailable

by blnkjns on Thu Jun 03, 2021 12:15 am

Are they within the LORA range (2-5km)? Then maybe your school can set up a LoRa gateway, that's the thing that I'm working on for our school to get implemented for the next school year. Modules like these can offer the needed radio, make sure it's the correct one for your local LoRa network frequencies.
https://www.adafruit.com/product/3072
https://www.adafruit.com/product/3073
We also do things with regular GSM, using SMS. Sim card with 55 SMS or 55 minutes is 5€, they are for grabs at the local grocery store, no questions asked, with true phone number, so for very low-data needs this might work well. It basically gives you 55x160 chars of data. Great for daily updates or building GPS trackers and such. If you only need to receive data, it is very cheap. If kids manage to hook data on the speech channel, you can push it to 3000-5000kB per minute, giving you like 275 kB for 5€.

Other nice developments are the new 5G data modules. They come with some very cheap data plans. Here in the Netherlands you can get free SIM cards for this network with 1MB of data. Not a big amount, but they are free and if you call the provider as school/teacher, you can get more than the usual 5 per person limit. It works with boards like these
https://www.adafruit.com/product/3998
https://store.arduino.cc/arduino-mkr-nb-1500-1413
But I advise you to check a more complete tutorial for it so see all about your local situation.

blnkjns
 
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Re: Ideas to connect to devices when wifi unavailable

by brubell on Fri Jun 04, 2021 9:27 am

+1 for Blnkjns' suggestion of running a local LoRaWAN network, but your school's IT may not be so keen about putting a what is essentially a router on their network...

Have you reached out to the IT department in your district?

brubell
 
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Joined: Fri Jul 17, 2015 10:33 pm

Re: Ideas to connect to devices when wifi unavailable

by blnkjns on Fri Jun 04, 2021 5:21 pm

Yes, they have a bunch of unused IP addresses, one is used to participate in some neutrino-detecting network, one will be reserved for the LoRa gateway. So yes, it is all discussed.

blnkjns
 
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Joined: Fri Oct 02, 2020 3:33 am

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