Reading serial from arduino on nodemcu and "capturing" variable

Using Arduino Programming Questions
1

Hi there,
i am strugling for past few days and really dont know what am I missing.
Doing this as hobby so pls don't judge.

My set up Arduino reads sensor (light) sends data to NodeMcu who sends it to localhost.

The thing i am struggling is i cant extract variable coming from Arduino ..
the code:

how output should work:

void setup() {
// Open serial communications and wait for port to open:
Serial.begin(115200);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
}
void loop() { // run over and over
if (Serial.available()) {
Serial.write(Serial.read());
}
}

OUTPUT

520.00
710.00
1020.00
640.00

Now if i try to Serial.read() and store it as variable i get gibberish and values which i cant use. Any attempt to mess with 1st code i get this result

void loop() { // run over and over
if (Serial.available()) {			
float arrivingdatabyte = Serial.read();
delay(1000);
Serial.println(arrivingdatabyte);  
}
}

OUTPUT
55.00
13.00
11.00
44.00
19.00

so pls can someone help me what am I doing wrong. Or @ least point me to right direction.
Many thanks.

2

Please read the online documentation on this site, for the read() method of the Serial class.

3

Data is sent over a serial link one character at a time so when you receive a character and print it, which is what you are doing, you see a print of a representation of the value one character at a time, not the actual value

If you want to turn what you receive into a value that you can use then you need to read each of the characters and convert the whole thing.

Start by looking at the Serial.parseFloat() function Serial.parseFloat() - Arduino Reference

However, I would question whether you need to use a float when an integer would probably suffice

I would also question whether you need the Arduino when the NodeMcu could read the sensor itself

4

thanks for yours reply...

i'm talking in n00b perspective, that i'm baffled by it, that this:

Serial.write(Serial.read())

can give you on serial monitor the value u seek, but Good forbid you try to "catch" it and reused in code .. it goes completely beserk

like i said .. tyvm

5

It is not giving you the value, rather it is printing each character of the value in turn

Have you tried Serial.parseInt() ?

6

@tandrli

Try the following (tested) setup and sketches:
uartnanoUno

NANO Simulator and Sender

#include<SoftwareSerial.h>
SoftwareSerial SUART(10, 11);

void setup()
{
  Serial.begin(9600);
  SUART.begin(9600);

}

void loop()
{
  SUART.print(520.00, 2);
  SUART.write(0x0A);
  //---------------------
  SUART.print(710.00, 2);
  SUART.write(0x0A);
  //---------------------
  SUART.print(1020.00, 2);
  SUART.write(0x0A);
  //---------------------
  SUART.print(640.00, 2);
  SUART.write(0x0A);
  //---------------------
  delay(1000);
}

UNO Receiver

#include<SoftwareSerial.h>
SoftwareSerial SUART(10, 11);
char myData[20];
byte counter = 4;

void setup()
{
  Serial.begin(9600);
  SUART.begin(9600);
}

void loop()
{
  do
  {
    byte n = SUART.available();
    if (n != 0)
    {
      byte m = SUART.readBytesUntil('\n', myData, 10);
      myData[m] = '\0';
      float x = atof(myData);
      Serial.println(x, 2);
    }
    counter--;
  }
  while (counter != 0);
  counter = 4;
}

Output: on SM2 (Serial Monitor 2)

520.00
710.00
1020.00
640.00
7

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