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discussion / Sensors  / 21 April 2021

(Arctic Fox) trap alarm based on LoRa Adafruit

Lars Holst Hansen

Lars Holst Hansen

Aarhus University
Biologist and Research Technician working with ecosystem monitoring and research at Zackenberg Research Station in Greenland
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I managed to get a working protoype of a LoRa based trap alarm system. 

I based it on Adafruit Feather M0 RFM96 LoRa Radio (433 MHz) tranceivers based on a little experience with other Adafruit M0 microcontrollers.

I designed the system with a "base station" and a number of "trap nodes". 

The sensor on the trap nodes are simple reed or magnet switches that will trigger when a magnet is moved away and I use a combination of beeps and blinks on the base to indicate the various states of the traps.

The hardest part was to make the arduino codes to make this all happen but I got some help from my wife (used to programming). 

I could not find many examples of useful code using these particular boards but I found something similar I could learn from. I really ought to properly docement me own project and share it...

My code is not very clean at all and probably much longer than it needs to be to accomplish what I want but the main thing for me is that it works... 

I have had a few looks at freaklabs.org and freakduino boards. It seems chibiarduino really take some of the complexity out of the coding and will make it much easier for people not used to programming. I consider watching the bould you own data logger videos and might consider these for future projects - but I believe the 900 MHz frequency used is not allowed in Europe so unless there will be a 433MHz I might have to pass.   

Cheers,



Akiba
@Freaklabs
Freaklabs
I'm an engineer and product designer working on wildlife conservation technology.
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22 April 2021 12:29pm

Hi Lars.

Thanks for checking out the FreakLabs boards. Actually we are planning product lines specifically for conservation technology and the wireless products will be based on LoRa with both 433 MHz and 900 MHz support. Also you may be interested in the follow-on course to the Buid Your Own Datalogger course which will be Build Your Own Sensor Network featuring LoRa as the main wireless protocol. The name is still a work in progress, ha ha ha. This is slated for later this year, once the DataLogger course is wrapped. 

In any case, looking forward to working with the conservation community to develop useful tools that specifically address community needs :)

Akiba

Robin Sandfort
@capreolus  | he/him
Capreolus e.U.
wildlife biologist with capreolus.at
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22 April 2021 2:07pm

Hi Lars and Akiba,

did I miss something? The "standard" LoRaWAN frequency in Europe is 868 MHz. Most networks do not work with the also allowed 433 MHz. So please also consider 868 Akiba ;-)

Greetings,
Robin

Paul Geraghty
@PaulG
tinkerer / programmer
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23 April 2021 5:53pm

As stated, LoraWAN is 868/900mhz, and while more complex, can certainly be more useful in terms of nett coverage providing you are willing to invest in a more power hungry gateway. I am using the simpler 433mhz in P2P (point to point) mode which is what I think you are alluding to. I use this partly because I read somewhere (on here I think) that the signal from 433mhz is slightly better through woodland. I cannot attest to it being better, but it certainly does work well with no LOS (line of sight) through the canopy - only tested at about 1km so far (plateau to valley). Even simple P2P LoRa radios have quite a few settings which let you play with channels, power and much more. Essentially with LoRa though you have to pick a single channel and stick with it. I've been using these things : https://www.electrodragon.com/product/atmega328p-arduino-plus-lora-sx1278-board-loraduino/ a 433mhz radio and essentially an Arduino pro-mini, with a few hacks you can get the power use right down too. These are as cheap as chips whereas the Adafruit kit is usually really nice, good docs etc but a get bit expensive once you try and scale up. This future course sounds good.