Home (Room) Temprature and Humidity Monitor With Web Based Chart - Raspberry Pi

Simple way to monitor your, Home ,room, garage small factory or any other places Temperature and Humidity from anywhere in the world via internet.

It very fun and very simple.

Step 1: The Concept

The Raspberry Pi will get the Home(Room) Temperature and the Humidity from the DHT11 sensor.
All the data will be POST to the web server via JSON RAW data method.
Data will store in a data base and publish to a chart.
We can monitor the Temperature and Humidity with the chart.

Step 2: Required Items and Pre Requests

1 X DHT11 Sensor
1 X Raspberry Pi B board (New) with Raspbian installed.
Cable to connect
Need an internet connection
Installing Python And GPIO libraries : Install Python and GPIO Libraries
Setup a Web Server :
- Setup Apache, MySql and PHP on Ubunutu
- Setup Apache, MySql and PHP on Centos

Step 3: Connecting the Device

Make sure the power is switched off.
Connect the VCC to the +3 V.
Connect the DATA to the GPIO 4.
Connect the GND to the GND.
Power on the Raspberry Pi

Step 4: Setup the Python File in the Raspberry Pi

Connect to the Raspberry Pi via SSH or connect directly. select a proper folder or location to create the file.

example :Desktop

nano dht11.py

And Download the attached dht11.py file and copy the source to your file in the Raspberry Pi.

All the functions and methods i have explained in the code with comments.

My web server IP address is "104.236.91.122" and the web service PHP file is "/rpi/rpi.php"

dht11.py
Download

Step 5: Setup the PHP Web Service

Download the rpi.rar file and extract the files.

Open phpMyadmin and create a new database example : "rpi_themo".

Download the "pi.sql" file and import to your new database. (i have inserted few sample data)

Change the data base credentials in the following files

\rpi\db-con.php
\rpi\temp\assets\php\getTemp.php

Step 6: Testing the Device

Connect to the Raspberry Pi and go to your dht11.py file location.

run the below comand

sudo python dht11.py

you will get something like this :

New record created successfully

if you get something like this :

no_data

don't worry this has a chance to lose data. This is because Raspberry Pi is not running at a real-time system, the delay in the program is not accurate enough, and sometimes that leads to a failure of transmission.we can run the program for several times can pick the correct result.

Step 7: Automating This Process

As you know in Linux we can run any script using cron jobs hence i have added a record in the cron jobs for run the script every minute. Use the following script for add the script.

crontab -e

add the following line in the bottom

*/1 * * * * sudo python /home/pi/Desktop/dht11/dht11.py

save and exit, for make sure the record has added. type the following comand

crontab -l

then you can see the record.