send dht11 data from arduino to another arduino and print to lcd

Other Hardware Displays
1

hi guys . .

i've two arduinos, dht11, and lcd
the consept is to print dht11 data from arduino 1 to arduino 2 lcd . .

  • read dht11 ( done )
  • arduino 1 and arduino 2 connected ( done )
  • print on lcd arduino 2 ( problem )

tx --- rx
rx --- tx

arduino 1

#include <DHT.h>
#define DHTPIN 8
#define DHTTYPE DHT11

DHT dht(DHTPIN, DHTTYPE);

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

void loop() {
float kelembaban = dht.readHumidity();
float suhu = dht.readTemperature();
delay(400);
Serial.print(temperature);
Serial.print("*C");
Serial.print(" || ");
Serial.print(humidity);
Serial.println("%");

}
}

arduino 2

#include <LiquidCrystal.h>
LiquidCrystal lcd(6, 7, 2, 3, 4, 5);

int dat;

void setup()
{
lcd.begin(16, 2);
Serial.begin(9600);
delay(400);
}

void loop()
{
if (Serial.available()){
dat = Serial.read();
Serial.write(dat);
}
lcd.setCursor(0, 0);
lcd.print("Suhu||Kelembapan");

lcd.setCursor(0, 1);
lcd.print(dat);

}

helps :confused:

2

Hi Fadli, - I have just posted three ways for communicating data (temperature from a Dallas DS18B20) from one Arduino via standard serial, or Soft serial, or I2C serial communication to a secons Arduino. Display is on a 128x32 OLED, but that is secondary matter. Please visit

Wiring diagrams and sketches in the article!
Succes, Floris

3

Hi Fadli, the examples on theSolaruniverse.wordpress.com site deal with sending one float variable from Arduino 1 to Arduino 2.

What you want is to send two float variables, i.e. suhu and kelembapan, from Arduino 1 to Arduino 2
As serial communication only sends ASCII characters you must 'code' the floats into a string of ASCIi characters, transmit the string and in the receiving Arduino split the string, decode the two substrings into floats and voila - you got what you want.

Now reality. I am a newbie myself, but with help from posts on this fantastic forum I managed to write two sketches that work with Arduino 1 with a DHT11 sensor on pin 10, and with Arduino 2 with a 16x2 LCD display - note the wiring: lcd(12, 11, 5, 4, 3, 2)

connect TX of Arduino 1 with RX of Arduino 2 via an interruptor switch
connect RX of Arduino 1 with TX of Arduino 2 via an interruptor switch
(set switch in 'disconnected' position during uploads of sketches - or else you will get gibberish on the LCD display)
Do not forget to connect GND of both Arduinos

good luck.

Fahli_Arduino_LCD_serial.ino (2.72 KB)

Fahli_Arduino_DHT11_serial.ino (1.83 KB)