The code below displays the temperature and humidity from a DHT22, but also receives that same data from another arduino or atmega through an RF Link using VirtualWire and displays it as well.
VirtualWire can be downloaded from:
airspayce.com/mikem/arduino/VirtualWire/index.html
DHT22 Library from Adafruit: github.com/adafruit/DHT-sensor-library
LCD Library and DFR Key from Linksprite: Linksprite Wiki
// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain
#include "DHT.h"
#include
#include "DFR_Key.h"
#include
// PIN 11 = RX
#define DHTPIN 12 // what pin we're connected to
#define LCD_BACKLIGHT_PIN 10 // D10 controls LCD backlight
//some example macros with friendly labels for LCD backlight/pin control, tested and can be swapped into the example code as you like
#define LCD_BACKLIGHT_OFF() digitalWrite( LCD_BACKLIGHT_PIN, LOW )
#define LCD_BACKLIGHT_ON() digitalWrite( LCD_BACKLIGHT_PIN, HIGH )
#define LCD_BACKLIGHT(state) { if( state ){digitalWrite( LCD_BACKLIGHT_PIN, HIGH );}else{digitalWrite( LCD_BACKLIGHT_PIN, LOW );} }
// Uncomment whatever type you're using!
//#define DHTTYPE DHT11 // DHT 11
#define DHTTYPE DHT22 // DHT 22 (AM2302)
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
LiquidCrystal lcd( 8, 9, 4, 5, 6, 7 );
DFR_Key keypad;
DHT dht(DHTPIN, DHTTYPE);
int localKey = 0;
boolean displaycelsius = false;
boolean isstart = true;
boolean backlight = true;
boolean displayold = false;
float oldt = 0;
float oldh = 0;
float mint = 0;
float minh = 0;
float maxt = 0;
float maxh = 0;
float remt = 0;
float remh = 0;
float rempI = 0;
float rempM = 0;
float remt2 = 0;
float oldcelsius = false;
unsigned long previousMillis = 0;
long interval = 5000;
float h = 0;
float t = 0;
int displaymode = 4;
byte smiley[8] = {
0b00000,
0b00000,
0b01010,
0b00000,
0b00000,
0b10001,
0b01110,
0b00000
};
byte frownie[8] = {
0b00000,
0b00000,
0b01010,
0b00000,
0b00000,
0b00000,
0b01110,
0b10001
};
void setup() {
Serial.begin(9600);
// set up Receiver (first because it may set unused pins to wrong mode)
vw_setup(2000); // Bits per sec
vw_rx_start(); // Start the receiver PLL running
// set up LCD
lcd.begin(16, 2);
//Serial.println("DHTxx test!");
lcd.print("Getting Temp!");
dht.begin();
keypad.setRate(10);
digitalWrite( LCD_BACKLIGHT_PIN, HIGH ); //backlight control pin D3 is high (on)
pinMode( LCD_BACKLIGHT_PIN, OUTPUT ); //D3 is an output
// create a new character
lcd.createChar(1, smiley);
// create a new character
lcd.createChar(2, frownie);
LCD_BACKLIGHT(backlight);
}
void loop() {
uint8_t buf[VW_MAX_MESSAGE_LEN];
uint8_t buflen = VW_MAX_MESSAGE_LEN;
localKey = keypad.getKey();
if (localKey == LEFT_KEY)
{
lcd.clear();
displaymode = (displaymode + 1) % 6;
}
if (localKey == UP_KEY)
{
lcd.clear();
//displayold = !displayold;
}
if (localKey == RIGHT_KEY)
{
backlight = !backlight;
LCD_BACKLIGHT(backlight);
}
unsigned long currentMillis = millis();
if(isstart || (currentMillis - previousMillis > interval)) {
previousMillis = currentMillis;
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
h = dht.readHumidity();
t = dht.readTemperature(!displaycelsius);
/*LCD_BACKLIGHT_OFF();
delay(200);
LCD_BACKLIGHT_ON();*/
}
if(isstart || localKey == SELECT_KEY)
{
isstart = false;
oldh = h;
oldt = t;
minh = h;
mint = t;
maxh = h;
maxt = t;
if(backlight)
{
LCD_BACKLIGHT_OFF();
delay(200);
LCD_BACKLIGHT_ON();
}
}
minh = min(minh, h);
mint = min(mint, t);
maxh = max(maxh, h);
maxt = max(maxt, t);
lcd.setCursor( 0, 0 );
// check if returns are valid, if they are NaN (not a number) then something went wrong!
if (isnan(t) || isnan(h)) {
//Serial.println("Failed to read from DHT");
lcd.print("Sensor Error ");
lcd.setCursor( 0, 1 );
lcd.print(" ");
} else {
if(displaymode == 0)
{
lcd.setCursor( 0, 0 );
lcd.print("Temp.: ");
lcd.print(t,1);// Serial.print(t);
lcd.print("F ");
if((int)t>=68)
lcd.write(1);
else
lcd.write(2);
lcd.setCursor( 0, 1 );
lcd.print("Humid.: ");
lcd.print(h,1);// Serial.print(h);
lcd.print("%");// Serial.print(" %\t");
}
if(displaymode == 1) // show saved temps
{
lcd.setCursor( 0, 0 );
lcd.print("T: ");
lcd.print(t,1);// Serial.print(t);
lcd.print("F (");
lcd.print(oldt,1);// Serial.print(h);
lcd.print("F)");// Serial.print(" %\t");
lcd.setCursor( 0, 1 );
lcd.print("H: ");
lcd.print(h,1);// Serial.print(h);
lcd.print("% (");
lcd.print(oldh,1);// Serial.print(h);
lcd.print("%)");// Serial.print(" %\t");
}
if(displaymode == 2) // show min/max temps
{
lcd.setCursor( 0, 0 );
lcd.print("Max T: ");
lcd.print(maxt,1);// Serial.print(t);
lcd.print("F");
lcd.setCursor( 0, 1 );
lcd.print("Min T: ");
lcd.print(mint,1);// Serial.print(t);
lcd.print("F");
}
if(displaymode == 3) // show min/max humid
{
lcd.setCursor( 0, 0 );
lcd.print("Max H: ");
lcd.print(maxh,1);// Serial.print(h);
lcd.print("%");
lcd.setCursor( 0, 1 );
lcd.print("Min H: ");
lcd.print(minh,1);// Serial.print(h);
lcd.print("%");
}
if(displaymode == 4) // show local and remote
{
lcd.setCursor( 0, 0 );
lcd.print("LT:");
lcd.print(t,1);// Serial.print(t);
lcd.print(" LH:");
lcd.print(h,1);// Serial.print(h);
//lcd.print("F");// Serial.print(" %\t");
lcd.setCursor( 0, 1 );
lcd.print("RT:");
lcd.print(remt,1);// Serial.print(h);
lcd.print(" RH:");
lcd.print(remh,1);// Serial.print(h);
//lcd.print("");// Serial.print(" %\t");
}
if(displaymode == 5) // show Remote
{
lcd.setCursor( 0, 0 );
lcd.print("P:");
lcd.print(rempI,1);// Serial.print(t);
lcd.print("in ");
lcd.print(rempM,1);// Serial.print(h);
lcd.print("m");
//lcd.print("F");// Serial.print(" %\t");
lcd.setCursor( 0, 1 );
lcd.print("T: ");
lcd.print(remt,1);// Serial.print(h);
lcd.print(" (");
lcd.print(remt2,1);// Serial.print(h);
lcd.print(")");
//lcd.print("");// Serial.print(" %\t");
}
/*if(!animfirst || localKey == SELECT_KEY)
{
animfirst = true;
for (int positionCounter = 0; positionCounter < 16; positionCounter++) {
// scroll one position left:
lcd.scrollDisplayRight();
// wait a bit:
//delay(150);
}
// scroll 29 positions (string length + display length) to the right
// to move it offscreen right:
for (int positionCounter = 0; positionCounter < 16; positionCounter++) {
// scroll one position right:
lcd.scrollDisplayLeft();
// wait a bit:
delay(50);
}
}*/
}
if (vw_get_message(buf, &buflen)) // Non-blocking
{
int i;
digitalWrite(13, true); // Flash a light to show received good message
// Message with a good checksum received, dump it.
Serial.print("Got: ");
for (i = 0; i < buflen; i++)
{
Serial.print(buf[i], DEC);
Serial.print(" ");
}
Serial.println("");
digitalWrite(13, false);
if(buf[0] == 200)
{
remh = (float) buf[1] + ((float) buf[2]) / 100.0;
remt = (float) buf[3] + ((float) buf[4]) / 100.0;
rempI = (float) buf[6] + ((float) buf[7]) / 100.0;
rempM = 100.0 * (float) buf[8] + (float) buf[9] + ((float) buf[10]) / 100.0;
remt2 = (float) buf[11] + ((float) buf[12]) / 100.0;
}
}
if(localKey != SAMPLE_WAIT)
delay(200); // delay to avoid key getting registered multiple times.
}
