LoRa with Electron v Arduino Mini

Troubleshooting
1

Hi Everyone,

I am using an electron with a SX1276 lora module to act as a receiver and I’m having a strange issue.

When I connect up the LoRa module to a Arduino mini, I get good range (100m in built up city).

When I connect up the electron to the same LoRa module the range drops to about 25m.

Would anyone have and idea why this might be?

Thanks!

2

@PeaTearDial, you may be getting RF interference from the Electron GSM modem. You may want to test with the the modem turned off.

2 Likes
3

thanks,

is

SYSTEM_MODE(MANUAL);
and
Cellular.off();

enough to turn off the modem? if so, it doesn’t seem to be of much help .

4

@PeaTearDial, yes, that should be enough. Can you provide a picture of your setup? How are you powering the SX1276 module?

5

Hey, powering the LoRa from the 3v3 pin on the particle. I tried power the sx1276 from the output of the mini while using the particle for communications but it didnt improve anything.

Capture.PNG468×616 427 KB

6

@PeaTearDial, can you also provide a picture of your arduino setup to compage against?

2 Likes
7

It’s ugly as hell but seems to work pretty good.

Capture.PNG433×725 432 KB

8

it seems that when the particle is connected, I don’t get values below -100 RSSI. When the Arduino is connected I can get values all the way down to an RSSI of -127.

9

Those radios can consume a good amount of current, so I don’t think the 3.3v rail on the Electron can supply the full power transmission rate on the LORA radio.

Try powering the radio from the Arduino power source while connecting the grounds between all units. This should tell you if it’s a power supply issue to the Lora Radio.

Also, are you using the same code that you are using on the Arduino on the Electron? I know I had to change some settings to get max range on my RFM95w radios + Photon setup.

10

Hey!

Yes I tried using the Arduino as VCC to no avail… had the same problem.

Yes im using the exact same code (just changed the SS and reset pins.)

https://go.particle.io/shared_apps/59e7cbeb07cb7f8ed1001451

11

No idea then.

I did get the RFM95w radios working if you don’t get this figured out.

1 Like
12

Thanks,

I might have to if i cant get this figured out!

13

Here is an overview of how to get the RFM95w up and running should you go that direction.

1 Like
14

Anyone else have any ideas?
Would really appreciate it!!

15

@PeaTearDial, the Arduino Mini runs at 8MHz while the Electron runs at 120MHz. This affects SPI bus speed. Power requirements on 3V3 may also be an issue.
Do you have a link to the code you are running?

16

Hey, here's the link!

Shouldn't the electron be able to supply 800mA? From datasheet:

This pin can be used as a 3.3V power source with a max load of 800mA.

17

@PeaTearDial, code looks good and you are correct about the current capacity on 3V3. How are you powering the Electron?

18

I’ve powered the electron a few different ways.

  1. through a micro to USB phone connector
  2. battery & micro to usb phone connector to see serial data
  3. phone connected through a USB battery pack.
  4. Connected to PC – > took the sender for a walk.
19

@PeaTearDial, in all cases, did you have a fully charge LiPo connected to the Electron?

20

Well I’m not sure if it was fully charged but definitely over 90%.

When I had it connected to my PC I didn’t have the LiPo connected.