First experiment: a simple gas detector

by Marco Lamanna

Let's begin assembling some stuff from starter kit...as first example we will try to build a simple "gas detector" using MQ-4 sensor.

Here is the datasheet

The sensor has 3 pins:

- Vcc: 5V supply voltage, Arduino friendly;
- GND: ground connection;
- AD: analog output; provides a value congruent with the gas concentration in the air;
- D0: triggered digital output; provides an HIGH signal when the gas concentration exceeds a limit; you can set this limit through the trigger;

We will use only the analog output, which will be linked to an Arduino's analog input pin.

The sensor needs a pre-heating time.

In our prototype, just for example, we will use also:

- a temp sensor: LM 35
- an LCD display 16X2 backlighted with Hitachi HD44780 driver
- a Buzzer
- a led
- a pot

On the display we will show datas provided by the sensors; led and buzzer will be used to signal warnings and alerts and the pot controls the LCD display dimmer.

Here is the demonstration video: