# MQ3 Gas Sensor(EF05032)

## Introduction

The MQ3 Gas sensor is tin dioxide (SnO2), which has a low conductivity in clean air. While the sensor being put in an environment that exists the alcohol vapor, the electrical conductivity of the sensor increases as the concentration of alcohol gas in the air increases.

![](./images/05032_01.png)
## Products Link

[ELECFREAKS PlanetX MQ3 Sensor](https://shop.elecfreaks.com/products/elecfreaks-planetx-mq3-sensor?_pos=1&_sid=c15ac07d8&_ss=r)


## Characteristic


 Designed in RJ11 connections, easy to plug.

## Specification


Item | Parameter 
:-: | :-: 
SKU|EF05032
Connection|RJ11
Type of Connection|Analog output
Working Voltage|3.3V


## Outlook



![](./images/05032_02.png)

## Quick to Start


### Materials Required and Diagram

 Connect the MQ3 Gas sensor to J1 port and the OLED to the IIC port in the Nezha expansion board as the picture shows.


![](./images/05032_03.png)

***Note:*** A preheating for 3 minutes after powering on is required before using.

## MakeCode Programming


### Step 1

Click "Advanced" in the MakeCode drawer to see more choices.

![](./images/05001_04.png)

We need to add a package for programming, . Click "Extensions" in the bottom of the drawer and search with "PlanetX" in the dialogue box to download it. 

![](./images/05001_05.png)

***Note:*** If you met a tip indicating that the codebase will be deleted due to incompatibility, you may continue as the tips say or build a new project in the menu. 

### Step 2

### Code as below:

![](./images/05032_06.png)


### Link
Link: [https://makecode.microbit.org/_A0b2Ri6Lp4aD](https://makecode.microbit.org/_A0b2Ri6Lp4aD)

You may also download it directly below:

<div style="position:relative;height:0;padding-bottom:70%;overflow:hidden;"><iframe style="position:absolute;top:0;left:0;width:100%;height:100%;" src="https://makecode.microbit.org/#pub:_A0b2Ri6Lp4aD" frameborder="0" sandbox="allow-popups allow-forms allow-scripts allow-same-origin"></iframe></div>  


### Result
 The value detected from MQ3 Gas sensor displays on the OLED screen.

## Python Programming 


### Step 1

Download the package and unzip it: [PlanetX_MicroPython](https://github.com/lionyhw/PlanetX_MicroPython/archive/master.zip)

Go to  [Python editor](https://python.microbit.org/v/2.0)

![](./images/05001_07.png)

We need to add enum.py and ethanol.py for programming. Click "Load/Save" and then click "Show Files (1)" to see more choices, click "Add file" to add enum.py and ethanol.py from the unzipped package of PlanetX_MicroPython. 

![](./images/05001_08.png)
![](./images/05001_09.png)
![](./images/05032_10.png)

### Step 2

### Reference

```
from microbit import *
from enum import *
from ethanol import *
ethanol = ETHANOL(J1)
while True:
    display.scroll(ethanol.get_ethanol())
```


### Result
 The value detected from MQ3 Gas sensor displays on the micro:bit.

## Relevant File


## Technique File