LoRa node vs concentrator setup

Project help
1

Hi there,

I am looking for some clarifications around LoRaWAN and TTN. I find the existing documentation all a bit unclear and confusing.

My end goal is to have two Rasberry Pi using LoRa. One is supposed to be a node and send temperature data from a 1-wire thermometer via LoRa to my second Raspberry Pi which in turn sends the data to the TTN network.

For the gateway/concentrator I try to follow these instructions - Deploy a LoRa Basics™ Station gateway with TTN and balena.

I have a Dragino LoRa/GPS_HAT, but it is not working. This HAT is based on the SX1276/SX1278 transceiver. The docs for the Balena Basic Station mention SX1301 and SX1302.

So my first question is whether this is just a question of missing support for SX1276 in the Balena project or whether there is a requirement to have a HAT with SX1301/SX1302. I am trying to figure out whether the hardware required for a node and a gateway is conceptually different or whether I can use the same HAT (provided it is supported) for both, the node as well as the concentrator.

The RAK2245 RPi HAT seems to be really hard to get atm. Any idea whether this HAT from Waveshare would work? It seems to have the right chip.

Last but not least, I am looking for an example on how to code/setup the node. How do I send the temperature data via LoRa? Which library do I use and what does the payload look like? The documentation I can find is not coherent and things seems to even got harder with TTN’s v2 vs v3 protocol. This repo - GitHub - btemperli/LoRaPy: LoRaWAN implementation in python - is atm my best guess on what to use on the node side, but I am still at loss how to package my data. Assuming my Dragino LoRa/GPS_HAT is not suitable as a concentrator, would it work for the node?

Any help appreciated,
Hardy

@mpous any ideas?

1 Like
2

Hi @hardy thank you for asking! This is a very good question!

As far as I know, the hardware that you have (Dragino LoRa Hat) is using a transeiver that i think it’s single channel. Usually the concentrators for gateways use 8 channels and single-channel gateways have been deprecated (read more here). So my recommendation is not to build a gateway with that hat but instead make a node if you have LoRaWAN / TTN coverage. For that, I recommend to check the TTN coverage map.

If you still want to build a concentrator… let’s think on that :slight_smile:

If you are going to use the LoRa hat as a node with TTN, you must use The Things Stack V3.

Related with the payload formats, that’s a great question. To be honest with LoRa i don’t have a lot of experience on the node side, creating payloads from scratch. My recommendation would be:

  • send the temperature as is (in hex) and on TTN create a decoder function to convert the hex temperature into decimal (at the end you are shipping easy data).
  • use an existing payload format (e.g. Cayenne LLP) Find more information here and decode it with the methods TTN has.

I hope this helps! I would love to see a LoRa node balenified :slight_smile:

Let me know if you would like to jump into a call to learn more!

3

Hi,

As far as I know, the hardware that you have (Dragino LoRa Hat) is using a transeiver that i think it’s single channel. Usually, the concentrators for gateways use 8 channels and single-channel gateways have been deprecated (read more here ).

Ahh, that’s what I was looking for. That makes sense. I wish this kind of thing would be clearly stated somewhere. So I need a multi-channel concentrator. I took the plunge and ordered the Waveshare concentrator. I could not find a RAKxxx HAT anywhere. All stock seems sold out.

So my recommendation is not to build a gateway with that hat but instead make a node

I’ll try that next.

if you have LoRaWAN / TTN coverage.

That’s the rub. There is a concentrator 8km away. It might or might not work, but since the concentrator is not under my control I won’t have much of a way debugging the whole setup. If it just works, great. If not, then it will be hard to get to the bottom of things without also controlling the concentrator.

If you still want to build a concentrator…

Eventually, I’ll have my own :slight_smile:

If you are going to use the LoRa hat as a node with TTN, you must use The Things Stack V3.

Got you.

Related with the payload formats, that’s a great question. To be honest with LoRa i don’t have a lot of experience on the node side, creating payloads from scratch. My recommendation would be:

  • send the temperature as is (in hex) and on TTN create a decoder function to convert the hex temperature into decimal (at the end you are shipping easy data).
  • use an existing payload format (e.g. Cayenne LLP) Find more information here and decode it with the methods TTN has.

Ok, thanks for the tips. I’ll look into it.

I hope this helps! I would love to see a LoRa node balenified :slight_smile:

Same here. I could image a Balena Block which handles the LoRa communication. It could offer some form of REST API which other services in your app can use to send their payload. WDYT?

Let me know if you would like to jump into a call to learn more!

Thanks. I think I will take you up on this soon :slight_smile:

1 Like
4

I think this is a great idea! maybe over-engineered but it looks great!

if it’s ok for you and you want to build in the open sharing your fights here, it could be really nice to help you async from here :slight_smile:

looking fwd to see this! i’m about to order the same of you… need to find a place with availability :crossed_fingers:

1 Like