LoRa SX1278/SX1276 modules support

Hardware Radios
1

Hi!
I wonder why there is no any FW development to support these powerful and cheap modules? There are full variety of them for 433, 868, 915, 100mw and 1w. Price is ridiculous starting from $4 to $8.
It was already implemented incredibly long range free LRS for these modules, that also supports Mavlink telemetry, but there is no any only telemetry dedicated FW.
Would be very nice to have it. Looks like it can be most cost effective link ever made.

http://www.cdebyte.net/lora-module/sx1278-lora-module/sx1278-lora-module-semtech-buy-for-water.html

2

Hello,

The main issue on Lora is the bandwidth … if you want to use Lora modulation the TX is really really low so that isn’t suitable for telemetry

3

Yes, it is slow for full telemetry, but for most main parameters it still can be very useful.
It can be used to drive AAT, or to show position on map, as well as add waypoints or lunch other mission commands. For most of the flights we don’t need raw sensors data and other bulky things.

1 Like
4

I totally agree! Even in it’s most extreme long range settings, the bandwidth is still on par with those of the Apollo missions. And crossfire is based on the SX1276 LoRa chip from Semtech.
Mostly I think the issue is that the lightest (and cheapest) modules can’t simply be connected to a serial port: They only talk SPI and that is often not broken out in an easily accessible way. Still, I hope one day someone will write a communication back-end for them!

5

No, that’s not an issue - most of the LoRa modules have UART interface.
The only issue that someone needs to code a new FW. ) That’s it.

6

I bought these: https://www.aliexpress.com/item/32852066531.html?spm=a2g0s.9042311.0.0.27424c4d3JRSBl
They are dirt cheap and absolutely tiny and light. All the ones that I found with UART are basically this, but paired with an ESP32 for communication. E.g. the ones called “E32”: They are twice the size and the antenna connector alone weighs twice as much as the whole Ra-01 module. That seems overkill to me, when my FC (Omnibus F4 Pro V3) already has a spare SPI.
For those that indeed have UART, would we really need any changes in the FW? Won’t that be rather transparent, like HC-12s? At least that is how I envision it…

7

Are you all not aware of QLRS. It’s been done and many people use them for longe range fpv.
https://www.rcgroups.com/forums/showthread.php?2837542-QCZEK-LRS-DIY-433MHz-1W-(30dBm)-LORA-RC-LINK-with-telemetry

8

I’ve mentioned Qlrs in the first message, as you can see, just without naming it. But Qlrs doesn’t work like telemetry modem, it uses mavlink encapsulation, and it requests telemetry packets, which is completely different scenario. So it doesn’t really help. We don’t discuss LRS systems here.

9

Gotcha. Not sure it will be easy or even possible as LORA seems to present some challenges. QLRS 2.0 does have a full bi-directional Mavlink option but it is only for parameter configuration. It is very slow and it cannot run RC at the same time. You can switch in and out of that mode.

If anyone wanted to further develop this I imagine Kris would be helpful (QLRS Developer).

10

there is also https://dronee.aero/products/zoon-long-range-telemetry-module?variant=21348623679566

11

Is there any updates on support of Lora on Ardupilot?

12

As it was mentioned before Lora is not capable to support really useful fast link, but for the slow one there is a perfect solution:

13

I don‘t want to buy other Tx/Rx modules to have lora chip on them.

I wanted lora for Manual flight only. I see its bit rate is enough.

14

This topic is about telemetry modems.

15

I got it.

What is the minimum bitrate required for telemetry?