Air Quality Sensor. Carbon Dioxide, Carbon Monoxide, Oxygen, Temperature, Humidity

I wanted know the air quality at home so I designed a sensor for it.

With this detector I can monitor the CO2 (carbon dioxide), CO (carbon monoxide), O2 (oxygen), Temperature and humidity.

Also I've put buzzer, relay, 0-10v output and LED in it, to don't only monitor them but also be able to control something by threshold values.

The temperature alarm is adjustable and the LCD backlight is auto adjusted.

The main ingredients:

- PIC16F1939

- MH-Z19

- LM358

- OPA2333

- LCD 16x2

- DHT22

- ME2 CO

- ME2 O2

-Relays

-Buzzer

-LEDs

-Photoresistor (LDR)

The schematic is in the video with all the components.

I first drew the schematic and after I designed the PCB layout.

I used the Easy-PC designer.

I ordered the PCB from a PCB manufacturer and I soldered the components by hand, because I don't have pick and place machine :) 

I imagined how I want this sensor to work and I interpret this for the microchip in C language, so I wrote the software for the chip.

For this I used the MPLAB.

I've put everything together and programmed the microchip.

You can see the result in the video on the top of the page.