LCD_Weather

Arduino UNO project that displays the temperature and humidity on an onboard LCD display.

License

This software is licensed under the MIT License.

Hardware

This project utilizes the following parts:

• Integrated Circuits, Boards, Active Components
  • Arduino UNO R3 (or similar)
  • LCD1: 16x2 character LCD screen, 16-pin HD44780 interface.
• Electromechanical Components and Sensors
  • S1: Switch (I'm using an ON-ON SPDT)
  • U1: Potentiometer. (This is used as a variable voltage divider, so almost anything works. However, I'm using a single-turn 1/2 watt 1K ohm pot. It's available here: https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=2118803)
  • RHT1: DHT11 Digital Temperature and Humidity Sensor (I'm using a sensor module from a kit where the RHT1 sensor, R1 resistor, and associated wiring that's on Breadboard2 is all attached to the sensor, similar to this: http://www.jameco.com/z/HUMI-01-OSEPP-DHT11-Humidity-and-Temperature-Sensor_2237116.html. If your sensor is an independent 4-pin sensor, the one on Breadboard2 is set up the way you need.)
• Passive Components
  • R1: 5 ohm resistor. See RHT1.
  • R2: 10 ohm resistor.
  • VCC1: 9V battery and snap connector.

Circuit Diagrams

Software

The software is fairly straightforward.

Prerequisite Libraries

• LiquidCrystal, included with Arduino, to run the LCD display.
• SimpleDHT to run the DHT sensor.

The Code

The code is broken into four sections.

• Intro Comments describe the purpose of the code and lists the pin arrangement.
• Globals contains the global variables and objects used by the code.
• Arduino Code contains the setup() and loop() functions that Arduino uses to run.
• Helper Functions contains helper functions that are called by the setup() and loop() functions.