Need help Grove LoRa 433mhz


I have a problem with the module Grove LoRa 433mhz Module’s link

I plugged the module on a UART of Grove Meda shield, I use sketch examples (RF95_client / RF95_server) of seeeds library and it says “Init failed”.

What should I do to correct it?

Thank for your help

(I hope you can understand me, I’m french and I can’t speak english very well)

Here is the sketch
[code]// rf95_client.pde
// -- mode: C++ --
// Example sketch showing how to create a simple messageing client
// with the RH_RF95 class. RH_RF95 class does not provide for addressing or
// reliability, so you should only use RH_RF95 if you do not need the higher
// level messaging abilities.
// It is designed to work with the other example rf95_server
// Tested with Anarduino MiniWirelessLoRa

#include <SoftwareSerial.h>
#include <RH_RF95.h>

// Singleton instance of the radio driver
SoftwareSerial ss(5, 6);
RH_RF95 rf95(ss);

void setup()
Serial.println(“RF95 client test.”);

if (!rf95.init())
    Serial.println("init failed");

// Defaults after init are 434.0MHz, 13dBm, Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on

// The default transmitter power is 13dBm, using PA_BOOST.
// If you are using RFM95/96/97/98 modules which uses the PA_BOOST transmitter pin, then 
// you can set transmitter powers from 5 to 23 dBm:
//rf95.setTxPower(13, false);



void loop()
Serial.println(“Sending to rf95_server”);
// Send a message to rf95_server
uint8_t data[] = “Hello World!”;
rf95.send(data, sizeof(data));


// Now wait for a reply
uint8_t buf[RH_RF95_MAX_MESSAGE_LEN];
uint8_t len = sizeof(buf);

    // Should be a reply message for us now   
    if(rf95.recv(buf, &len))
        Serial.print("got reply: ");
        Serial.println("recv failed");
    Serial.println("No reply, is rf95_server running?");



Dear Customer

For your question, I did an experiment, which really reproduced what you said, such as graph.

This link will fail, because the hard serial port is used, and we need to use the soft serial port, so initialization failure will occur.

The following is the application of software serial port, which is able to run successfully.

,If you can not solve your problem, please affix your link circuit diagram, convenient for us to communicate.


seeed techsupport team


here is the picture of the connection

it is plugging into D4 and D5, so i change softwareserial ss (5, 6) by (4, 5) in the sketch RF95_server

still the same

Dear Customer

Please change ss(5, 6) to ss(10, 11).


seeed techsupport team


thanks it works

rf95 client test fails with 433MHz modules


Can I do the same setup as Damder (the initial one) but plug the Lora Grove to the I2C.
It is written in the documentation of Seeeduino V4.2 that I2C SCL and SDA are connected to A4, A5.
Why it doesnt work if I do

SoftwareSerial SSerial(A4, A5); // RX, TX
#define COMSerial SSerial
#define ShowSerial Serial
RH_RF95 rf95(COMSerial);


Hello, can I connect the Grove - LoRa Radio 433 MHz to my Arduino Uno R3 directly through RX and TX ports present in the board, if I don’t have the UART interface? I want to communicate two LoRa Radios successfully. Kindly someone assist me. It’s very urgent.

Hi @tiwari73rajesh, Sorry I didn’t get your question. if you looking for UART port’s, then you can use the SoftwareSerial() and you can use your GPIO pins as UART!

The Arduino hardware has built-in support for serial communication on pins 0 and 1 (which also goes to the computer via the USB connection). The native serial support happens via a piece of hardware (built into the chip) called a UART.

This hardware allows the Atmega chip to receive serial communication even while working on other tasks, as long as there room in the 64 byte serial buffer.

The SoftwareSerial library has been developed to allow serial communication on other digital pins of the Arduino, using software to replicate the functionality (hence the name “SoftwareSerial”). It is possible to have multiple software serial ports with speeds up to 115200 bps. A parameter enables inverted signalling for devices which require that protocol.

I am using Arduino Uno R3. Actually, I don’t currently have UART interface devices like Seeeduino lotus or Grove Base Shield V2.0. So I am trying to use the Grove - LoRa Radio 433 MHz by connecting it to the RX (0) and TX (1) ports available on my board (as you know that one RX and one TX port is available in an Arduino Uno Board). But I’m not able to perform successful client test.

This is my question. How to perform successful client-server test and use the the LoRa radio, without any UART interface, by connecting it directly to the Arduino UNO board?
I am facing problems and for clearing my confusions, I need a detailed procedure and guidance. I’d be very grateful to you.

Are you getting any error or something? If yes please share the error!

Since the Grove LoRa Radio is requiring UART port, you need to use that, otherwise, you need to use the RFM95 Module via SPI, which required modification and soldering and all.

@tiwari73rajesh You can post here, So others can also suggest a better solution if there is avilable :slightly_smiling_face::+1:

This is my connection pattern. Take a look at the images.

2nd image

This is the 3rd image

@tiwari73rajesh, what problem you are facing while using the module? Any compilation or uploading error?

Nope… Codes of both the client as well as the server were compiled and uploaded successfully to the boards.
As seen in the pictures uploaded by me, I am not using any UART interface or SPI or converters. Neither I have any of these devices available with me right now nor can I get them now, so I am trying to use the transceiver with the help of the RX(0) and TX(1) ports available on the arduino boards. Kindly assist me on how to use this without any extra conversion devices. If you want I can send you my connecting pattern also.

Waiting to hear from you…

@tiwari73rajesh The UART interface has the pin’s named Rx and Tx since you already connected to Rx and Tx , so you already connected via UART interface.

If you facing transmission issues, check the jumper cable continuity and make sure that all are good.

I’ve fitted all the jumper cables precisely and in the right manner…
What to do?
This is the most I could do… Not beyond this :woozy_face:… I’m trying…
Attached the output of failed communication :roll_eyes:

Please look into this.

Hi @tiwari73rajesh, Can you check the Jumper wire continuity!