32. MQ3 Gas Sensor(EF05032)

32.1. 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.

32.2. Products Link

ELECFREAKS PlanetX MQ3 Sensor

32.3. Characteristic

Designed in RJ11 connections, easy to plug.

32.4. Specification

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

32.5. Outlook

32.6. Quick to Start

32.6.1. 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.

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

32.7. MakeCode Programming

32.7.1. Step 1

Click “Advanced” in the MakeCode drawer to see more choices.

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.

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.

32.7.2. Step 2

32.7.3. Code as below:

32.7.4. Link

Link: https://makecode.microbit.org/_A0b2Ri6Lp4aD

You may also download it directly below:

32.7.5. Result

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

32.8. Python Programming

32.8.1. Step 1

Download the package and unzip it: PlanetX_MicroPython

Go to Python editor

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.

32.8.2. Step 2

32.8.3. Reference

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

32.8.4. Result

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

32.9. Relevant File

32.10. Technique File