Weather Monitoring System – 2018

Project Goal

To build a weather monitoring system to measure temperature and humidity using a TIVA C Series launchpad.

Components

 

 

 

1. TIVA C Series Microcontroller (TM4C123GH6PM)

 

 

 

 

 

 

 

2. DHT22 Sensor

 

 

 

 

 

 

 

 

3. 16×2 LCD Display

 

 

 

 

 

4. 10k resistor

 

 

 

 

Description

In this project, we monitor weather parameters such as temperature and humidity using a DHT22 sensor.The sensor is interfaced with TM4C123GH6PM micro controller and the measured value is displayed on LCD module.

Block Diagram

 

Methodology

DHT22 humidity and temperature sensor gives a precise value of both temperature and humidity measurement.Humidity measurement range is 0 to 100% RH(Relative Humidity) and temperature range is -40 to 80 degree celsius. Single-bus data is used for communication between MCU and DHT22, it costs 5mS for single time communication. Data is comprised of integral and decimal part. DHT22 send out higher data bit first. DATA=8 bit integral RH data+8 bit decimal RH data+8 bit integral T data+8 bit decimal T data+8 bit check-sum. If the data transmission is right, check-sum should be the last 8 bit of “8 bit integral RH data+8 bit decimal RH data+8 bit integral T data+8 bit decimal T data”. when MCU send start signal, DHT22 changes from low-power- consumption-mode to running-mode. When MCU finishes sending the start signal, DHT22 will send response signal of 40-bit data that reflect the relative humidity and temperature information to MCU. Without start signal from MCU, DHT22 will not give response signal to MCU. One start signal for one time’s response data that reflect the relative humidity and temperature information from DHT22. DHT22 will change to low- power-consumption-mode when data collecting finish if it don’t receive start signal from MCU again.

 

 

 

 

 

 

 

Experimental Set-Up and Results