that works with the DHT sensor.  Slowly I added the declarations from the Ultrasonic sketch. (All OK)

Then from the Void setup sketch, each line of code uploaded so I could see the incoming messages still arrived on the other UNO.  Until I added  "mySerial.begin(9600);"  Then it stopped sending.  So what was it?   Very simple.  int pinRX = 11; int pinTX = 10;   Wrong way around !!!!!  Doh!!

Hours have been burned.  Off to the PUB to drown my sorrows.  Then back to finishing the project.

Regards, Village Idiot.

I think it’s best if I summarise what happened BEFORE I started hacking / adding code.

Code from the Drone Workshop’s 2 seperate examples (JSN-SR04T sensor in Mode1 )

and from the 433Mhz Tx/Rx using the Radiohead library Demo2 where Bill uses a DHT22.

Both these sketches compile without error and work fine on the same UNO if Uploaded and run separately.

No buffer overflow issues.  No delay in transmission …. All good.

Movements in front of the Ultrasonic Sensor…..  all responded quickly.

I proceeded to combine them without changing or adding any code.

The Ultrasonic code was gradually added to the original 433Mhz code. 

In the void loop()section I added the Ultrasonic code before the Radio code.

So the only change I made then was to move the “{“ from the bottom of the Ultrasonic code

to the last line of the sketch.

No compile errors.  No code additions, no alterations (except “{“) downloaded OK.

No response at the receiver.

After that, I started experimenting and then posted where I left off.

Which I apologise, must have been confusing.

I think next I will go back and change the “original merge” within the Void Loop() and place

the Radio code first, and the Ultrasonic code last, initially, without changing anything.

****** will get back to you sometime when I have done this. ******

Cheers for now.    JimJtron 6/4/22.

Posted by: @zander

@frogandtoad I wonder what will happen if he removes 1 char from hello, that may change the memory addresses going from 5 to 4. I am still 100% convinced he has a buffer overflow issue that is stomping on some critical piece of memory. It's been decades since I used gcc, is there a compiler directive that will show the address map of the compiled code, and how do you pass compile time switches in the arduino IDE?

It's possible, but I did not review the whole code... the missing pointer was the first thing I spotted, which is 100% incorrect.  There seems to be a whole mix of legacy C code with a sprinkle of C++ code here... a great recipe for problems :-)

Posted by: @jimjtron

// ************************************************
// ADD this piece from Radiohead examples for debugging purposes.
const char msg1 = "hello"; // removed * before msg1
rf_driver.send((uint8_t *)msg1, strlen(msg1));
rf_driver.waitPacketSent();
delay(200);
// ************************************************

   // ADD this piece from Radiohead examples for debugging purposes.
   const char msg1 = "hello"; // removed * before msg1

Just an FYI: - Removing the asterisk is a complete mistake, and should not even compile.

Do you have your compiler warning turned up in your preferences?

By removing that, you're actually introducing bugs in your code.

Cheers

So I have not tampered with that section.  I'm still highly suspicious that the Ultrasonic's code method is "hogging" the time needed for the *msg to slowly transmit out. 

Anyhow, an update.

This is the receivers output with the TimeStamp feature turned ON.

Started here:-

14:13:09.484 -> Humidity:   - Temperature:

14:13:22.712 -> Humidity:   - Temperature:

14:13:31.576 -> Humidity:   - Temperature:

14:13:40.416 -> Humidity:   - Temperature:

etc.

14:41:08.972 -> Humidity:   - Temperature:

14:41:22.228 -> Humidity:   - Temperature:

14:41:26.978 -> Humidity: 50.00  - Temperature: 23.40

14:41:31.045 -> Humidity: 50.00  - Temperature: 23.40

14:41:39.909 -> Humidity: 50.00  - Temperature: 23.40

14:41:53.155 -> Humidity: 50.00  - Temperature: 23.40

14:42:02.002 -> Humidity: 50.00  - Temperature: 23.40

14:42:10.865 -> Humidity: 50.00  - Temperature: 23.40

14:42:15.255 -> Humidity: 50.00  - Temperature: 23.40

14:42:24.118 -> Humidity: 50.00  - Temperature: 23.40

etc.

So the Delay is 14:41 minus 14:13hrs. = 28 minutes !!!

It would be interesting to know WHY ?????

Regards, JimJtron.