Basic RYLR890/896 test circuit not working

Other Hardware Sensors
1

I'm making an attempt to use an RYLR896 module, however it is not working. Any input would be much appreciated.

I have looked at a number of tutorials, both video and text, and have tried to boil it down to a simple proof-of-concept design.

The connections seem quite simple:

Arduino - RYLR896:
3.3v to Vdd
gnd to gnd
Tx to Rx
Rx to Tx

This is my code. It reads a "sensor" (variable resistor.) Distilled from this page:

(Note however, I could not get the code as written in the article to work either. I also tried another example which used SoftwareSerial, but couldn't get it to work either.)

Transmitter:

int vresistor = A0; 

void setup() {
  Serial.begin(115200); 
  pinMode(vresistor,INPUT); 
}

void loop() {
  int sensorvalue = analogRead(vresistor);
  String sensorvaluestr = String(sensorvalue);
  String datalength = String(sensorvaluestr.length());

  String mymessage = "AT+SEND=0," + datalength + "," + sensorvaluestr + "\r\n";
  
  Serial.println(mymessage); 

  delay(100); 
}

Receiver:

void setup() {
  Serial.begin(115200); 
  Serial.print("AT\r\n");
  delay(100); 
}

void loop() {
  if (Serial.available()) { 
    String rcvdData = Serial.readString();
    Serial.println(rcvdData); 
  }
}
2

A schematic would be appreciated.
Can you see the transmitter messages on the serial monitor?

(And why Strings?)

4

RYLR_schem

That is the transmitter, the receiver is the same except without the pot.

(And why Strings?)

Because I was getting errors when I just tried concatenating the ints.

5

You don't need to concatenate anything.
The serial line will do that for you :wink:

6

"You don't need to concatenate anything.
The serial line will do that for you :wink:"

But doing it the way I did shouldn't make it not work, should it?

7

It shouldn't, I agree, but I like to keep things simple.

Anyway, good luck.

8 
String mymessage = "AT+SEND=0," + datalength + "," + sensorvaluestr + "\r\n";
Serial.println(mymessage);

is not as simple as this?

Serial.print("AT+SEND=0,");
Serial.print(int);
Serial.print(",");
Serial.print(int);
Serial.println("\r\n");

Or is there another way of doing this of which I am unfamiliar?

9

IMO, the second is simpler.
And it has the huge (IMO) bonus that it doesn't use Strings.

10

Oh, I get it now. I assume Strings use a lot of processing/memory.

11

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