Hey, what's up, guys? Akarsh here from CETech.
In this article today we are going to learn about the RFM LoRa modules made by HopeRF.
We will be seeing what are the features that the RFM module has to offer, its pinout, comparison between the different RFM modules available in the market like RFM95 96 97 and RFM98.
We will also compare the RFM98 with other famous LoRa module available in the market like the Ra-02 made by Ai-Thinker or the RYLR896 by Reyax.
The RFM module is very popular due to the cheap price and availability in different frequency bands, unlike the Ra-02. Due to this, you will find the RFM module in various LoRa based products like nodes or even gateways.
I've made a tutorial video on this, I recommend you check it out.
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Step 1: Parts That You See in the Tutorial
Step 2: Get PCBs for Your Project Manufactured
You must check out JLCPCB for ordering PCBs online for cheap!
You get 10 good quality PCBs manufactured and shipped to your doorstep for 2$ and some shipping. You will also get a discount on shipping on your first order. To design your own PCB head over to easyEDA , once that is done upload your Gerber files onto JLCPCB to get them manufactured with good quality and quick turnaround time.
Step 3: About the RFM Module From HopeRF
The RFM LoRa modules are SPI based LoRa modules.
They have 16 pins with a pitch of 2mm. They have the exact same physical footprint and pin spacing as the famous ESP8266 ESP12 module. Hence you can use the same SMD to through hole adapter with both the modules to break out the pins for use with a breadboard or a standard protoboard.
You can find the detailed specs in the datasheet: https://cdn.sparkfun.com/assets/learn_tutorials/8...
If you want to use the RFM module with an Arduino or esp based board you can use this library from adafruit:
GitHub Library: https://github.com/akarsh98/RadioHead-
Step 4: Comparison Between RFM95/96/97/98
The main difference between the RFM modules is that they operate on different frequencies.
As all the countries do not support the use of the same frequency band for free you need to used different module in different country. You can find about the free to use frequency band in your country from this webpage: https://www.thethingsnetwork.org/docs/lorawan/freq..
The RFM95 & RFM96 both operate in 868/915 band. Whereas the RFM97/98 work in the 433MHz band.
There are other minor differences in the spreading factor and sensitivity which you can take a look at in the table attached.
Step 5: RFM95 Vs RA02 Vs RYLR896
Now moving on to the comparison between the LoRa modules from HopeRF, AiThinker and Reyax.
1) RFM module by HopeRF: SPI
2) Ra-01/2 by Ai-thinker: SPI
3)RYLR896 by Reyax: UART using AT Commands
1) RFM module by HopeRF: 4.2$
2) Ra-01/2 by Ai-thinker: 3.7$
3) RYLR896 by Reyax: 15$
Frequency band availability:
1) RFM module by HopeRF: 433/868/915MHz
2) Ra-01/2 by Ai-thinker: Only 433Mhz
3) RYLR896 by Reyax: 433/868/915MHz
Ease of usability:
1) RFM module by HopeRF: Moderate with a decent amount of wiring and addition of Radiohead Library
2) Ra-01/2 by Ai-thinker: Moderate with a decent amount of wiring and addition of Radiohead Library
3) RYLR896 by Reyax: Easy with 2 UART wires and no need of any libraries or complex functions.
Step 6: Summarized
So as we saw there is no real winner that has an edge in all the situations.
It mostly depends on the use case of your project/product what module suits you the best according to its price and features as discussed above.
Anyways, If you have any requests or project request you can let me know in the chat thread below and I will surely consider it.
I recommend taking a look at my YouTube channel as I have done many LoRa videos there:
Participated in the
Arduino Contest 2019