Which LoRa Module to use


(Chris 1) #1

I am new to LoRa and have no clue which LoRa module(s) to use in my project(s).

For now, I have a Dragino Shiled with a RF96 LoRa chip, which works fine. However, the shield is too expensive to be used in multiple projects (i.e., 1 per project). So my question is, what LoRa modules are you using in your projects? Any particular recommendation?


(LoRaTracker) #2

Well, the Dragino uses an Hope RFM96, and and they are popular for projects.

There are a couple of alternatives, such as the Dorji DRF1276 or the RN2483 which has its own LoRaWAN stck built in.


(Chris 1) #3

Ok cool, thanks for your feedback!

I am currently building a beehive scale using a bare bones arduino. I will power it with a 3.7 V battery, so I guess this should work with the Hope RFM 96 (3.3 V) without any voltage regulator? However, what if I were to power my bare bones Arduino with 5 V?

Also, how do you connect the RFM96? I noticed the pin holes are not the standard 2.54 mm apart… Solder an individual cables in each hole?


(Jeff Uk) #4

I recall a forum thread starting a couple of months back where folk started listing all the LoRa/LoRaWAN modules they knew of…I don’t have time right now but may be worth you searching for that, there are also lots of examples on the forum and elsewhere on the interweb of connecting & using the modules to various MCU’s and embedded boards…Use forum search or GIYF :wink: When you find something(s) you are considering its then worth asking back here for experience & guidance/gotchas to avoid/work around etc.


(LoRaTracker) #5

I will power it with a 3.7 V battery, so I guess this should work with the Hope RFM 96 (3.3 V) without any voltage regulator?

Unfortunatly your ‘3.7V battery’ is likely a LiPo, which is actually 4.2V fully charged. That exeeds the operating voltage (3.7V) and the absolute maximum voltage (3.9V) of the LoRa device and can damage it and/or lead to unreliable operation, dont do it.

However, what if I were to power my bare bones Arduino with 5 V?

Use logic level converters, or just stick to 3.3V Arduino. 3.3V Pro Minis are popular.

Also, how do you connect the RFM96? I noticed the pin holes are not the standard 2.54 mm apart… Solder an individual cables in each hole?

Most people design their own PCBs, there are PCBs to buy out there too.


(Jac Kersing) #6

For LoRaWAN on TTN make sure to use 868/915MHz modules, 434MHz is not (widely) used.


(Ud Lo Ra) #7

There are also alternatives to RFM9x almost equivalent (or clones), one of which is HDP13. I have one version of it that is also 5V safe and breadboard friendly, plus shielded which is not bad.

A further alternative is to have a complete LoRa board like Lora32U4 or ESP32+LoRa, both relatively cheap (and complementary).


(Somsak) #8

@chris_1
You might try to look some more lora alternative products on www.tindie.com. Using lora or lorawan in searching product keyword. Even though, you do not wish to buy the product, it is sometimes useful to view source code and documentation link on product page.

Most of my work, I use Hope RFM95w. I also use LORA1276-C1 from NiceRF
and HPD13A from CFsunbird sometimes.


(Chris 1) #9

Dear All,

Thank you all very much for your feedback, that’s been really helpful!

I already have two RFM96 at hand and will probably try to make them work with an Arduino Pro Mini or with a bare bones Arduino using a logic level converter, as suggested by @LoRaTracker (as suspected by @LoRaTracker, I am using a LiPo battery having 4.2 V when fully charged).

For future projects, I will also evaluate the other modules suggested in this thread. Thanks again.


(Chris 1) #10

I had a look at how logic level converters work (never heard of them before) and as I understand it, you need e.g. a 5 V and a 3.3 V reference voltage. How do I do this with my 4.2 V battery as the only power source?


#11

1- use a 3v3 arduino and 3v3 sensors

you only need to convert your lipo voltage to 3v3 and you don’t need a level converter for I/O

you can use something like this (called buckboost)
-https://www.ebay.com/itm/2in1-Buck-Boost-0-8-6V-to-3-3V-DC-DC-Converter-Module-for-esp8266-Wifi-Bluetooth-/272426902863

you find many of these boards- step down step up buckboost ect
input from 0.8 to 6 v -> output steady 3v3

so if you drain your battery to say 2.6 v… the output is still 3v3 and your arduino still works.
if you connect your fully charged battery @ 4.2 v also the output is 3v3 no problemo

2- use a 5v arduino and 5v sensors

use 5v I/O sensors and you don’t need a level converter

you need a so called boost module to make the 5v from the lipo
best is then to choose a combination of dc dc boost converter and lipo charger.

example

now you can leave your lipo attached to the device and plug in an adapter to charge

3- a mix… 5v arduino and 3v sensors / 3v3 arduino and 5v sensors

then you make it yourself difficult :sunglasses:

add an extra dc dc converter from 5v to 3v3 so you have the 2 voltages needed for the levelconverter board

* I didn’t search for the cheapest dc dc ect. also depends on the capacity they can deliver


(Ud Lo Ra) #12

… however, this way the issue with the LoRa module remains, unless using the one I mentioned (that already include converters). To be safe, two logic level converters like this one are needed for the LoRa module (though maybe just one is sufficient for the inputs - I do not remember the number needed).

There are too many variables. Willing to use a LiPo, I would buy a LoRa32U4 that has everything inside, including LiPo charger, is 3.3, etc. And cheap.


(Chris 1) #13

Thanks for your input. I found in the past that the electromagnetic waves emitted by the coils on buck-boost converters could interfere with my HX711, as well as with LoRa.

Having done some research, I now consider using a HT7333 regulator instead, as described e.g. here:


#14

I was coming there in point 3… your to fast :wink:
And indeed the easiest setup is a complete board with all the components.

it’s nice to leave your device on while charging for example, but also think of lipo protection against overcharging ect.
a led indication on the board when your lipo is fully charged… little things, but also depends on the use case.


(Chris 1) #15

Sounds good! :+1:


(LoRaTracker) #16

You asked about using your 5V arduinos with a LoRa device, so clearly the 5V supply is available and presumably the 3.3V also.

Never tried logic level converters where one side is 4.2V and the other is 3.3V, its just so much easier these days to power everything from a 3.3V supply.


(Vtomanov) #17

I have very good experience with ESP32 LoRa module and Feather 32u4 LoRa - if you need CPU power and complicated calculations ESP32 is the way to go - fir low power consumption Feather 32u4 is a lot better - prices are about £15 for both modules in aliexpress


(Wijnand) #18

Is the CC1310 maybe an alternative? For Arduino Pro Mini + RFM95 see:

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