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A smoke detector module for 3D printer


A smoke detector module for 3D printer

One of the easy to find module for this purpose is displayed here.

Those sensors are often capable of detecting several types of Gaz/smoke/molecules.





Sensor main caracterisitics:

This model is a MQ2 gaz sensor module for arduino.

It can detect

  • Smoke
  • Hydrogen
  • Alcohol
  • MethanePpropane
  • I-buane
  • LPG.

It has 2 types of outputs:

  • Analog
  • Digital

The input voltage is 5V and the power consomption is about 800mw when « heating ».

Why does it consumes 800mW?

It can consume up to 800mW because the sensor needs to be at a certain temperature to operate properly.

In order to be warm enough, it’s equipped with a heating element that requires the 800mW to increase the sensor inner temperature.

The sensor needs a few seconds to be ready after switch on.

As the sensor needs to be at a certain temperature, you need to wait a few seconds so that it gives you the proper information.

If you both switch on the 3D printer and the sensor at the same time, the printer might detect from the very beguining some false alarm.

To prevent this:

  1. Power on the sensor module
  2. Wait a few seconds
  3. Power the 3D printer

The anolog output:

The sensor has an analog output.

The output voltage is proportional to the amount of particles detected.

On this output you cannot adjust the sensibility of the sensor as all is handled by a microcontroler or an electronic circuitry afterward.

The digital Output:

This output mainly uses the analog output value to operate and is triggered based on some voltage limit.

WIth this output you can adjust the sensibility of the sensor based on the blue trim at the back of the sensor.





Adjusting the trigger limit:

In addition to the blue trim, a red led will also switch on once the limit has been reached.

So you can adjust the level of this trigger by placing the sensor in the desired test environement and manually adjust the trim so that the led switches on or off.

You can use some humidificator to create smoke,smoke machine, cigarette smoke or even acetone or air spray to trigger the sensor.

Note: It’s important to know that the sensor reacts to the alcohol contained inside airspray as well as Acetone vapors.

So applying airspray during a print might trigger the alarm!

Also cleaning your heatbed with acetone while the sensor is on might also trigger it.

The wiring diagram:

This diagram shows an example on how to wire the module to a Ramps 1.4 board.

The board on the left allows to convert a 12V power supply into a 5V 1A power output.

The already available output pins are very nice to wire the sensor with a simple set of wires with connectors.

The current firmware of the Scalar 3D printers is able to use this sensor.

A ground wire also links the 5V breadboard with the ramps board.

In this example we are using the Digital output of the sensor as we can easily adjust the trigger level with a simple screw driver.

You can also use the analog output of this sensor, but you will need to play a little bit with the firmware settings as well as the debug outputs in order to adjust the trigger level.

The plastic housing

We already made some plastic housing models available on thingiverse:

The current housing are specialy made so that you can fix all the different boards into 3030 aluminum extrusions (used in Scalar 3D printers)

Full kits available:

Full kits are available on our store:


  • 12V to 5 V 1A regulator board
  • MQ2 sensor module
  • 1 set of wires with dupont terminals