433MHz-Using RadioHead constructor argument to change rx/tx pins

aw410 · January 15, 2023, 2:13pm

Hi all,

I am having a hard time getting RadioHead Library with the (RH_ASK Class) to change from its default pin parameters. RadioHead states that Pin 12 is default for Tx and 11 is default for Rx, but I need to change Rx to pin 10.

I am using arduino nano and a cheap set of 433MHz Transmitter and Receiver linked below on amazon:

According to RadioHead, I should be able to use the command below to change the parameters but I am having no luck:

RH_ASK driver(2000, 10, 12, 11);

My Transmitter Code:

// Include RadioHead Amplitude Shift Keying Library
#include <RH_ASK.h>
RH_ASK driver(2000, 10, 12, 11);
// Include dependant SPI Library 
#include <SPI.h> 
 
// Create Amplitude Shift Keying Object
RH_ASK rf_driver;

void setup()
{
  Serial.begin(9600);
    // Initialize ASK Object
    rf_driver.init();
}
 
void loop()
{
    const char *msg = "test message";
    rf_driver.send((uint8_t *)msg, strlen(msg));
    rf_driver.waitPacketSent();
    delay(1000);

}

My Receiver Code:

// Include RadioHead Amplitude Shift Keying Library
#include <RH_ASK.h>
RH_ASK driver(2000,10,12,11);
// Include dependant SPI Library 
#include <SPI.h> 

// Create Amplitude Shift Keying Object
RH_ASK rf_driver;
 
void setup()
{

    delay(1000);
    rf_driver.init();
    // Setup Serial Monitor
    Serial.begin(9600);

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

} 

void loop()
{
    // Set buffer to size of expected message
    uint8_t buf[12];
    uint8_t buflen = sizeof(buf);
    // Check if received packet is correct size
    if (rf_driver.recv(buf, &buflen))
    {

      // Message received with valid checksum
      Serial.print("Message Received: ");
      Serial.println((char*)buf);         
    }


}

I can post schematics as needed, but note receiver data pin -> 10, ad transmitter data pin -> 12.
Any help is much appreciated.

jremington · January 15, 2023, 4:21pm

What does that mean? Please explain what you expect to happen, what happens instead, and what you have done to debug the problem.

Such constructions with RH_ASK have always worked for me.

By the way, you don't need radios to bench test your work. Use wires to make the connections for testing (be sure to connect the grounds).

aw410 · January 15, 2023, 4:37pm

Thanks for your help. I was expecting to have the message "test message" come through on the Serial monitor. Instead my serial monitor stays blank. My goal is similar to the tutorial: Using 433MHz RF Modules with Arduino | DroneBot Workshop, if that helps.

Question for you if you have done this in the past, am I making a mistake calling for RH_ASK twice?
1st time: RH_ASK driver(2000,10,12,11);
2nd time RH_ASK rf_driver;

I am new to Arduino as a whole so please go easy on me.

jremington · January 15, 2023, 4:39pm

Yes. Get rid of the second. Why did you change the name of the instance, when you added the first?

It is always a good idea to verify that one of the examples from the library runs, before making ANY modifications to the code.

aw410 · January 15, 2023, 5:05pm

I was using the instance "rf_driver" from the tutorial, and "driver" from RadioHead's website. That was definitely some of my issue.

Thank you for the tip on examples. So in the new changes, I used RadioHead's examples for both the transmitter and receiver, then edited the driver for my pins. Below is the updated code for both. Unfortunately I am still not receiving anything, I used a multimeter and found a fluctuating current between GND and Data on the transmitter, so I have reason to believe it is transmitting. Any other thoughts?
Transmitter:

#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, 10, 12, 11); 
 
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:

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

RH_ASK driver(2000, 10, 12, 11);
 
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[5];
    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);

      Serial.print("Message Received: ");
      Serial.println((char*)buf);  
    }
}

jremington · January 15, 2023, 5:27pm

Did that work as expected?

Any other thoughts?

Test without the radios, using wires as already suggested.

Connect TX on the transmitting Arduino to RX on the receiving Arduino, and GND to GND.

aw410 · January 15, 2023, 5:51pm

After trying that, I am still not receiving anything. I am assuming you meant attaching TX to RX and not pin 12 to pin 10 (transmitter to receiver).

I noticed (with the multimeter) that I do NOT see any current or sign of a signal being sent from the TX pin on my transmitter arduino.

jremington · January 15, 2023, 5:57pm

Have you still not established that the RadioHead library example works "out of the box", with the default wiring?

aw410 · January 15, 2023, 6:12pm

I have and it does NOT. Is the built-in arduino Tx led supposed to signal when it is transmitting? With the original code provided by RadioHead, I see no signal to the Tx pin.

anon57585045 · January 15, 2023, 6:20pm

No. That is the serial port TX.

jremington · January 15, 2023, 6:23pm

If that test was done with radios, then the radios are at fault. Test the default library code using direct wire connections, as previously described.

If none of those things work, post a clear, focused picture of your setup. The wiring is probably at fault (poor solder connections, wrong breadboard connections, etc.).

It really helps if you answer the questions forum members ask. Reduces the amount of back and forth required to pry out the needed information.

aw410 · January 15, 2023, 7:21pm

My transmitter is already on a pcb and uses the exact connections default with RF_ASK. I have gone ahead and tested each circuit for a good connection and it looks great. This is pictured below:

My receiver however is attached with jumpers (the male ends are soldered to the receiver), I also tested these for good connection and they were fine. I don't have a breadboard so this was the best I could do with a camera. Black>5v, Brown>GND, White>D11:

Just to reiterate, this setup is not functional with the code posted on RadioHeads website for Receiver and Transmitter.

I apologize, I assumed since you requested that in post #4, that we had covered that.

anon57585045 · January 15, 2023, 7:24pm

Is there an antenna on the receiver? It's a tiny fuzz ball in the image. Oh, now I see one side. What is the CS pin supposed to connect to?

aw410 · January 15, 2023, 7:28pm

In the picture no, I removed it so it would fit through the roll of solder for a camera stand. I have tested it however with the antenna and still nothing.

I also just swapped it for a different receiver and it didn't change the result.

jremington · January 15, 2023, 7:28pm

How do you know the PCB is correct? We can't tell anything from those photos. The PCB adds one more completely unknown quantity to debug.

I strongly recommend to get the setup working on a breadboard, verifying proper connections and functions of all components, before committing to a PCB.

Two comments: 9V batteries are a poor choice for Arduino projects, and those coiled wire antennas are terrible -- even useless when laid alongside a conductive surface, like a PCB ground plane.

anon57585045 · January 15, 2023, 7:29pm

and what is the CS pin

Also have you done the wire only test that was suggested (post #2)?

anon57585045 · January 15, 2023, 7:35pm

Is there a ground plane on your board? If not, your TX antenna will radiate strongly into the Nano. Even if there is, it will. You need to move it away from there. If nothing else, the location will kill the effectiveness of the antenna, as mentioned.

Ditch the coil-ey appendage and replace it with a 7" or so straight wire. Also put the same on the receiver.

aw410 · January 15, 2023, 7:41pm

Because I can test each circuit for resistance and get a positive result. I also made them with fusion, and can verify that the connections are correct. Here is a screenshot:

I don't actually know, but the tutorial I have found online (linked in post #3)suggests I don't need it.

I have, it was suggested in post #2 and tested in post #7 (still having an issue)

There is not, and I was unaware of that. Can I change the direction of the antenna or am I better off moving the entire component? I will replace the antenna to a 7" wire as well.

anon57585045 · January 15, 2023, 7:42pm

You have information you didn't post? Post everything you can.

anon57585045 · January 15, 2023, 7:43pm

Depends on the final purpose and direction of your project. If you are aiming for a good final outcome, you need to ditch the existing PCB completely.

Back off and do a few weeks of R&D and experimentation to get it right before you make another one. And do some research on everything.

Right now, you should do the wire only test to rule out software.

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433MHz-Using RadioHead constructor argument to change rx/tx pins

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