Simple msgs over RF 433 cheap modules using RH-ASK

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1

Hi!
I'm trying to send simple messages over the cheap RF 433MHz kit.
Using RadioHead library's examples it works just fine. I can receive the msg in hex numbers.
The thing is when I change the msg. The receiver still receive the msg, but I can't see it in serial monitor.

The example codes are the following:

Transmitter:

// ask_transmitter.pde
// -*- mode: C++ -*-
// Simple example of how to use RadioHead to transmit messages
// with a simple ASK transmitter in a very simple way.
// Implements a simplex (one-way) transmitter with an TX-C1 module
// Tested on Arduino Mega, Duemilanova, Uno, Due, Teensy, ESP-12

#include <RH_ASK.h>
#ifdef RH_HAVE_HARDWARE_SPI
#include <SPI.h> // Not actually used but needed to compile
#endif

RH_ASK driver;
// RH_ASK driver(2000, 4, 5, 0); // ESP8266 or ESP32: do not use pin 11 or 2
// RH_ASK driver(2000, 3, 4, 0); // ATTiny, RX on D3 (pin 2 on attiny85) TX on D4 (pin 3 on attiny85), 

void setup()
{
#ifdef RH_HAVE_SERIAL
    Serial.begin(9600);	  // Debugging only
#endif
    if (!driver.init())
#ifdef RH_HAVE_SERIAL
         Serial.println("init failed");
#else
	;
#endif
}

void loop()
{
    const char *msg = "hello";

    driver.send((uint8_t *)msg, strlen(msg));
    driver.waitPacketSent();
    delay(200);
}

Receiver:

// ask_receiver.pde
// -*- mode: C++ -*-
// Simple example of how to use RadioHead to receive messages
// with a simple ASK transmitter in a very simple way.
// Implements a simplex (one-way) receiver with an Rx-B1 module
// Tested on Arduino Mega, Duemilanova, Uno, Due, Teensy, ESP-12

#include <RH_ASK.h>
#ifdef RH_HAVE_HARDWARE_SPI
#include <SPI.h> // Not actually used but needed to compile
#endif

RH_ASK driver;
// RH_ASK driver(2000, 4, 5, 0); // ESP8266 or ESP32: do not use pin 11 or 2
// RH_ASK driver(2000, 3, 4, 0); // ATTiny, RX on D3 (pin 2 on attiny85) TX on D4 (pin 3 on attiny85), 

void setup()
{
#ifdef RH_HAVE_SERIAL
    Serial.begin(9600);	  // Debugging only
#endif
    if (!driver.init())
#ifdef RH_HAVE_SERIAL
         Serial.println("init failed");
#else
	;
#endif
}

void loop()
{
    uint8_t buf[RH_ASK_MAX_MESSAGE_LEN];
    uint8_t buflen = sizeof(buf);

    if (driver.recv(buf, &buflen)) // Non-blocking
    {
	int i;

	// Message with a good checksum received, dump it.
	driver.printBuffer("Got:", buf, buflen);
    }
}

Does anyone have an idea why it's not working when I change the msg?

2

Post the code that fails, using code tags.

3 
// ask_transmitter.pde
// -*- mode: C++ -*-
// Simple example of how to use RadioHead to transmit messages
// with a simple ASK transmitter in a very simple way.
// Implements a simplex (one-way) transmitter with an TX-C1 module
// Tested on Arduino Mega, Duemilanova, Uno, Due, Teensy, ESP-12

#include <RH_ASK.h>
#ifdef RH_HAVE_HARDWARE_SPI
#include <SPI.h> // Not actually used but needed to compile
#endif

RH_ASK driver;
// RH_ASK driver(2000, 4, 5, 0); // ESP8266 or ESP32: do not use pin 11 or 2
// RH_ASK driver(2000, 3, 4, 0); // ATTiny, RX on D3 (pin 2 on attiny85) TX on D4 (pin 3 on attiny85), 

void setup()
{
#ifdef RH_HAVE_SERIAL
    Serial.begin(9600);	  // Debugging only
#endif
    if (!driver.init())
#ifdef RH_HAVE_SERIAL
         Serial.println("init failed");
#else
	;
#endif
}

void loop()
{
    const char *msg = "hola";

    driver.send((uint8_t *)msg, strlen(msg));
    driver.waitPacketSent();
    delay(200);
}

That's the code I'm having trouble with.
The only modification is a change on the message.
The receiver code is the same I posted.

4

If the ONLY thing you changed is "hello" to "hola" in the transmitter code, then there can be no problem.

You must have changed something else.

Start with fresh copies of the original example programs, and try again.

5

You were right.

I tried again and it worked.
The problem was the distance between the transmitter and receiver.
When they're a Little bit far from each other, the rx light still blinks, but the serial doesn't show the msg.

6

Use antennas on the modules. A 17 cm piece of straight wire connected to the ANT terminal works well.