serial interface between uno+nodemcu ,reading data

Projects Programming
1

hello,

I interfaced the arduino uno with esp8266 nodemcu, and triying to read data from esp8266 which received data from arduino uno .

I want to read those data from Esp8266 and process it for next further process ,but unable to trad those data which i receive through Softwareserial.h RX ,TX
my code is like this,

#include <SoftwareSerial.h>
SoftwareSerial mySerial(2, 3); // RX | TX


#include <DHT.h>

#define DHTPIN 6                           //Pin D1
#define DHTTYPE DHT11
int incomingByte = 0;
DHT dht(DHTPIN, DHTTYPE);

char c = ' ';
void setup()
{

Serial.begin(9600);

mySerial.begin(115200);

 dht.begin();
  while (!Serial) {
    ; 
  }
  Serial.println("hi esp");
  float h = dht.readHumidity();                       
  Serial.println(h);
  float t = dht.readTemperature(); 
  Serial.println(t);

}

void loop()
{
if (mySerial.available())
{
mySerial.write('t');
delay(1000);
mySerial.write('h');
delay(1000);
}
}

I change all data pattern like hex ,binary decimal but it hasn't worked.

2

Have a look at the examples in Serial Input Basics - simple reliable ways to receive data. There is also a parse example to illustrate how to extract numbers from the received text.

The technique in the 3rd example will be the most reliable.

You can send data in a compatible format with code like this

Serial.print('<'); // start marker
Serial.print(value1);
Serial.print(','); // comma separator
Serial.print(value2);
Serial.println('>'); // end marker

...R

3

thanks for reply ,

but i still not understood it that how to recognise the data receive by the node mcu.

i just want to read the temperature data for arduino uno and receive by nodemcu to process further for task.

In order to do that what can I change in program for receive data from uno .....

pin connection are like these,

arduino uno pin 3 as TX - RX of nodemcu

arduino uno pin 3 as RX -TX of nodemcu

arduino uno pin Gnd - Gnd of nodemcu

arduino uno pin 3.3 - 3.3 of nodemcu

my nodemcu code arel like these......

#include <SoftwareSerial.h>
#include <ESP8266WebServer.h>
#include <ESP8266WiFi.h>

const char* ssid = "Vaahaka@321";
const char* password = "vaahaka@22018";

SoftwareSerial mySerial(13, 15);

IPAddress staticIP (192, 168, 1, 22);
IPAddress gateway (192, 168, 1, 9);
IPAddress subnet (255, 255, 255, 0);

void setup() {
  Serial.begin(57600);
  Serial.begin(9600);
  pinMode(4, OUTPUT);
  Serial.println();
  Serial.println("Server started");

  WiFi.begin(ssid, password);
  WiFi.config(staticIP, gateway, subnet);


  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}
void loop()
{
  
  Serial.println(t);
  Serial.println(h);

}

so,what can i change in code to receive those data on nodemcu..............

4 
mySerial.begin(115200);

Software serial may not work well for that high of baud rate.

5

Implement robin's code at the receiver side. Write complementing code for the transmitter

Based on his example 3 / 5, the basics of the transmitter:
1)
Print '<'
2)
Print temperature
3)
Print comma
4)
Print humidity
5)
Print '>'.

6

Start with SoftwareSerial working at 9600 baud. When you get everything working try a higher baud rate. I believe it should work at 38400 baud.

...R