Arduino Temperature Monitoring System
This repository will include the code samples for an ongoing series of Arduino experiments, starting with some really basic circuits and building up over time into a more advanced system.
The topic will be temperature monitoring, with the eventual goal being a distributed Internet of Things (IoT) system with multiple monitoring "nodes", a centralised communications hub for logging and display, and a web-accessible interface.
The parts list will evolve over time as the project progresses, but for the initial few experiments you will need just a few items:
- Arduino Uno or similar (Duemilanove or Nano also work)
- DHT11 Temperature Sensor
- 10K Resistor
- Hookup Wires
To work with the DHT11 and DHT22 sensors we will need to install the Adafruit DHT Library.
If you are using the Arduino IDE v1.6.4 or above you can install the library using the Library Manager.
Manual installation instructions to follow.
Lets start simple and just get some readings from the DHT11 and pass them back to the Serial interface. The wiring for this sketch requires just 4 connections as follows:
- DHT pin 1 to Arduino 5v
- DHT pin 2 to Arduino Digital Pin 2
- DHT pin 4 to Arduino ground
- 10K resistor between DHT pin 1 and DHT pin 2
Note: DHT pin 3 is left unconnected.
Code available in /_01-dht11-serial
Upload the sketch to your Arduino and then open the serial monitor console (Tools > Serial Monitor) to view the output.
Reads the temperature and heat index (feels like temp) in Celcius, relative humidity in %.
Sample output:
DHT11 Serial
Temperature: 19.00c Humidity: 88.00% Feels Like: 18.68c
Temperature: 19.00c Humidity: 88.00% Feels Like: 18.68c
Temperature: 19.00c Humidity: 88.00% Feels Like: 18.68c
Temperature: 19.00c Humidity: 87.00% Feels Like: 19.00c
Temperature: 19.00c Humidity: 87.00% Feels Like: 19.00c
Note: This sketch requires the
OneWireandDallasTemperaturelibraries.
Building on what we started in the previous experiment, this time we are going to use a Dallas DS18B20 temperature sensor. This is a temperature only device (no humidity) but is more precise and fast than the DHT11.
The wiring for this sketch is similar to the previous example, but we are using a different value for the resistor and the pin order has changed:
- DS pin 1 to Arduino ground
- DS pin 2 to Arduino Digital Pin 2
- DS pin 3 to Arduino 5v
- 4.7K resistor between DS pin 2 and DS pin 3
Code available in /_02-ds18b20-serial
Upload the sketch to your Arduino and then open the serial monitor console (Tools > Serial Monitor) to view the output.
Reads the temperature in Celcius.
Sample output:
DS18B20 Serial
Temperature: 20.37c
Temperature: 25.31c
Temperature: 27.37c
Temperature: 28.50c
Temperature: 29.37c
Temperature: 30.00c