# 3D Printing > 3D Printer Parts, Filament & Materials >  Prevent 3D Printer Fire with Smoke Signal

## Brian_Krassenstein

Many individuals leave their 3D printers unattended.  Whether they go to bed, run out to the mall, or just head outside to enjoy the nice whether, this can be a danger.  There have been several reported fires started from people doing just this.  One individual has launched a Kickstarter project for a device called Smoke Signal.  Basically it is a smoke detector that can be placed on or around the 3D printer to detect if there is smoke.  If smoke is detected it shuts all power off to the machine.  More details on this device can be found here: http://3dprint.com/18064/smoke-signal-3d-print-fire

Below is a picture showing how Smoke Signal connects to a 3D printer:

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## Geoff

Unfortunately no good if the fire has already started . Switching of the electrical won't do alot at that point .. well, it's not going to extinguish the flames.. 

Like a match starting a fire, once the fire is lit, the match is redundant.

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## Mjolinor

The best way is simply a thermal fuse on the head that opens at 300c, before a fire starts.

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## richardphat

Some extra safety would be to install the printer within an enclosure, which can resist to heat.

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## RAMTechRob

I'm thinking its a good idea if its cheap enough.  My PLA will start to smoke before a fire and my glass bed will contain the mess until the alarm goes off and shuts it down.

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## Roxy

> The best way is simply a thermal fuse on the head that opens at 300c, before a fire starts.


This is an important first step.  But what happens if the fire starts elsewhere.  For example, there is a lot of current going to the heated bed and the wires for that are always moving.  If the wires fatigue, eventually, you might end up with just a few strands of the wire bundle conducting all the current.  This could get very hot and start the wire's insulation on fire.   But the nozzle's thermal fuse is still thinking everything is OK.

And those stepper motors sure get hot!   They have that enameled motor wire in them.  That stuff actually burns if it gets hot enough.  Perhaps that would contain the heat, but in my case I have wires and plastic touching my stepper motors.   Once again, the nozzle's thermal fuse would still be thinking everything is OK.

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## 3dkarma

I would add a wifi shield to one of these (instructables.com) arduino temperature and smoke detectors and use it to send me real time reports of ambient temperature while printing, send an alarm if a temp spike or smoke detected and turn off the printer via an SSR (Solid State Relay) in case of temp spike / smoke.

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## Geoff

In 3 comments I'm convinced we can do a better job, what are we all waiting for?

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## RAMTechRob

Where do you think that guy got his ideas.  From all you smart guys that don;t know how to start a Kickstarter.  In the old days, you had to risk your own money to fund projects, now you just get other people to risk their money.

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## Geoff

> Where do you think that guy got his ideas.  From all you smart guys that don;t know how to start a Kickstarter.  In the old days, you had to risk your own money to fund projects, now you just get other people to risk their money.


I know how to start a kickstarter, but unless I was significantly ahead in my project, I would not add to the pile of steaming dung that is already on there. all I would be doing, is .. as you said, risking other peoples money and really. Some people can sleep at night doing that, me personally, I can't

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## Mjolinor

> In 3 comments I'm convinced we can do a better job, what are we all waiting for?


We already have it cracked at minimal cost and with maximum reliability. 

Don't leave your printer alone for long if it is switched on.

However you protect the thing there will always be ways that it can create life threatening havoc without triggering your alarm no matter how many sensors and cut outs you stick in there.

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## Solstie

I have thought a lot about this in the past since I am always printing big prints.

My printer has smoked for me before without lighting up... Definitely think a smoke detector right on the printer is bare minimum safety consideration.  It will at least give you a chance to check issues prior to a large fire.  But obviously won't catch all issues.  I have a regular battery operated smoke detector mounted on my printer.  I have been thinking I should hook directly to my printer to short the board if it goes off (which would then cut power).  Thought about adding thermistors, but so many potential power sources.... 

I like this product better because it is more robust by cutting off the power source on a separate system.  Seems like it would be reasonably easy to make yourself but the price also seems reasonable.  

My frame is a combo of wood and aluminum so definitely has me thinking... Good article!

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## Geoff

You know what? I think I'll stick to cutting my models into 10 hour prints.. 

I've never been a fan of leaving it on overnight, both for noise, fire and the fact my cat thinks the moving head is something to attack.  :Stick Out Tongue:

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