empowering creative people

Sensors > Gas & Smoke

Alcohol Gas Sensor MQ-3


$6.76 AUD, inc GST
$6.15 AUD, exc GST

More Views

Alcohol Gas Sensor MQ-3
6.76 AUD


$6.76 AUD, inc GST
$6.15 AUD, exc GST
Shipping Offer


  • $6.95 Standard (2-4 days, tracked)
  • $8.95 Express (Overnight*, tracked)
  • $3 Economy Post* (3-7 days, no tracking)
  • FREE Pickup (Newcastle only)

Shipping costs may increase for heavy products or large orders.

Exact shipping can be calculated on the view cart page.

*Conditions apply, see shipping tab below.


This alcohol gas sensor detects the concentration of alcohol gas in the air and ouputs its reading as an analog voltage. The concentration sensing range of 0.04 mg/L to 4 mg/L is suitable for breathalysers (the legal limit of breath alcohol concentration, or BrAC, in most US states is 0.08 grams per 210 liters, or 0.38 mg/L). The sensor can operate at temperatures from -10 to 50°C and consumes less than 150 mA at 5 V. Please read the MQ3 datasheet (153k pdf) for more information about the sensor.

Gas sensor with orange plastic case bottom view.


Connecting five volts across the heating (H) pins keeps the sensor hot enough to function correctly. Connecting five volts at either the A or B pins causes the sensor to emit an analog voltage on the other pins. A resistive load between the output pins and ground sets the sensitivity of the detector. Please note that the picture in the datasheet for the top configuration is wrong. Both configurations have the same pinout consistent with the bottom configuration.The resistive load should be calibrated for your particular application using the equations in the datasheet, but a good starting value for the resistor is 200 kΩ.

Pololu offer two breakout boards that make it easier to interface with these sensors: a Pololu carrier board and a SparkFun carrier board. The Pololu version is shown below.

Pololu MQ gas sensor carrier with sensitivity-setting resistor soldered in the vertical orientation.

Note: These sensors could have orange or blue plastic cases. There is no functional difference between the two colored cases.

This product is listed in:

Documentation and Resources:

Product Comments

Exact shipping can be calculated on the view cart page (no login required).

We deliver Australia-wide with these options:

  • $3 for Small Items (3-7 days, not tracked, only available on selected small items)
  • $6.95 for Standard Post (2-4 days, tracked)
  • $8.95 for Express Post (Overnight for Australia Post Next Day Network, tracked)
  • Pickup - Free! Only available to customers who live in the Newcastle region (only after we email you to notify your order is ready)

International Orders - the following rates are for New Zealand and will vary for other countries:

  • $11.49 for Pack and Track (3+ days, tracked)
  • $16.50 for Express International (2-5 days, tracked)

If you order lots of gear, the postage amount might increment based on the weight of your order.

Our physical address:

Unit 18, 132 Garden Grove Parade
NSW, 2289

Please checkout our customer service page if you have other frequently asked questions such as "do we do purchase orders" (yes!) or "are prices GST inclusive" (yes they are!). We're here to help - get in touch with us to talk shop.