Configuring a Pico and Lora P2P

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Hi There,
I have a Pico connected to a Lora SX126X module and a second Pico W connected to another SX126x module. I have them talking to each other using Lora with a library I found here.

The library appears really well written.

I’m just running the Ping example to start with and it seems to be working.

However I’m not sure what I should change to be compliant with Australian rules.

This page Australia
Has the following details

For AU915, we use Frequency Sub Band 2, also known as channels 8-15, or 916.8MHz through to 918.2MHz.

So do I simply change the freq=923 to something inbetween 916.8 and 918.2 say 917 as it’s roughly in the middle.

Configuration section from the ping example

# LoRa
sx.begin(freq=923, bw=500.0, sf=12, cr=8, syncWord=0x12,
         power=-5, currentLimit=60.0, preambleLength=8,
         implicit=False, implicitLen=0xFF,
         crcOn=True, txIq=False, rxIq=False,
         tcxoVoltage=1.7, useRegulatorLDO=False, blocking=True)

Thanks
David

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Hi David,

Great question!

It looks like you’ve fallen into the trap of LoRa vs LoRaWAN.
Since your devices are communicating outside of the LoRaWAN stack (i.e. not connected to a gateway). you should be good to send packets.

HOWEVER, since you are on the airwaves you still have to comply with ISM regulations (let me preface, I’m no lawyer and haven’t thoroughly studied these regulations).
This document outlines the usable frequencies for IoT applications and the maximum allowed power output, to be polite its best to setup P2P devices outside of local LoRaWAN frequencies.

PS: you can check local gateways with https://ttnmapper.org/

Keen to see your project done! You should send it through to Core to go on the projects page once you’ve finished it :slight_smile:

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Hi Liam,
I have read through that PDF and nothing leapt out at me saying that I shouldn’t pic something between 915 - 928 Mhz. I also checked out that Lora Wan map and there is nothing within 300km of me so I’m not likely to interfere during testing. :slight_smile:
I’m in the country in the NSW Northern Rivers area. Buying a ~$500 LoraWan router would be ridiculous for my project.
I’m not quite sure why I should be “polite” and choose some other frequency in fact I probably can’t choose another valid one legally or the devices are not capable of doing that anyway. Even with the prospect that LoraWan will enter my neighbourhood over time I doubt my application will cause any problems.
It’s a remote gate sensor that will send a signal when the gate is opened. At most 4-6 times a day.
I’m also considering sending some heart beat style status notifications every few hours. It also seems I’m using these modules as intended.

I have been thinking about sending in a project document to Core Electronics for publication as this seems like an interesting use of the technology.
Thanks for your input.
David

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Hi David,

Between 915-928 MHz is perfect, agree on the LoRaWAN router, definitely not necessary for your project (if ever you need to manage upwards of 50 or so nodes it might be nice to have but definitely out of scope).

Great to see a heartbeat signal included and yeah the due diligence of looking out for regulations and asking these questions is great!

Please do! It sounds like an amazing project and we’d + other Makers would love to see it :smiley:
Liam

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