DHT Sensor for Gary

Gary the gecko gets a bit funny about his environment so we have to keep an eye on his temperature and humidity. We could have gone a purchased one but that would have been too easy! One ATMega328, home brewed PCB, LCD screen, DHT11 sensor and a laser cut case and we are away!

Not many notes on this one as the PCB creation was experimental and I will be writing it up fully later.

Anyway, here are some pictures.

More pics:

The button is so it doesn't burn power with the backlight

Like this

Sensor in an old mic housing.

Gary

Gary

Code if you want it, un-tidied and barely changed from Adafruits code. You will want the library on the tutorial as well.

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 // Example testing sketch for various DHT humidity/temperature sensors

// Written by ladyada, public domain

#include "DHT.h"
#define DHTPIN 13     // what pin we're connected to
#include <LiquidCrystal.h>
LiquidCrystal lcd(5,6,7,8,9,10);
#define DHTTYPE DHT11   // DHT 11
// Connect pin 1 (on the left) of the sensor to +5V
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  lcd.begin(16, 2);
  lcd.clear();
  Serial.begin(9600);
  Serial.println("DHTxx test!");
  lcd.print("Starting...");
  dht.begin();
  delay(500);
}

void loop() {
  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  int h = dht.readHumidity();
  int t = dht.readTemperature();

  // 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");
  }
  else {
    Serial.print("Humidity: ");
    Serial.print(h);
    Serial.print(" %\t");
    Serial.print("Temperature: ");
    Serial.print(t);
    Serial.println(" *C");
  }

  //LCD Display
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp    : ");
  lcd.setCursor(11, 0);
  lcd.print(t);
  lcd.setCursor(13, 0);
  lcd.print("c");
  lcd.setCursor(0, 1);
  lcd.print("Humidity: ");
  lcd.setCursor(11, 1);
  lcd.print(h);
  lcd.setCursor(13, 1);
  lcd.print("%");
  delay(1000);
}

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