Jump to content
UltiMaker Community of 3D Printing Experts

Made a PLA smoke detector cap and it set it off

Recommended Posts

Posted · Made a PLA smoke detector cap and it set it off

Hello Everyone,


Got a bit of an odd question based on an odd experience.


I made some black smoke detector caps in an attempt to get some cheaper than $5 a piece, since We're looking to get a whole bunch of them and I can print them for $0.17 a piece in a printer.


It's a photoelectric sensor with an eye inside and if that sensor's shot gets interrupted or dispersed, it triggers the device and puts it into alarm.


So I made some and went to try one and it set the device off as if there was smoke all over it, I made it out of Bumat PLA, there was no logical reason for it to have happened but now I'm wondering why it happened.


Any of you guys have any experience on this? Original cap looks like the attached picture.




  • Link to post
    Share on other sites

    Posted · Made a PLA smoke detector cap and it set it off

    ... maybe first Google how a photoelectric sensor works...


    The original orange cap seems to be translucent, the black one you printed isn't! Don't play arround with smokedetectors, better be safe than sorry!

  • Link to post
    Share on other sites

    Posted · Made a PLA smoke detector cap and it set it off

    I did, the light originates from within the detector, I tested it on other ones with no problems.


    If you turn the lights off in a room and close the doors and there's no windows, the smoke detector doesen't go off, so the idea of the new cap blocking all light crossed my mind but didn't make much sense in the end.


    Can't seem to get another one to go off, perhaps the detector itself was faulty.

  • Link to post
    Share on other sites

    Posted · Made a PLA smoke detector cap and it set it off
    The "lightsource" is inside the smoke detector so it doesn't matter if you turn on/off the lights and if there is a window or not. 

    In an optical point smoke detector there is a photodiode and a light source. When smoke is added, the light is disrupted which is seen by the detector. In the direct method, the light source and detector are directly opposite each other. In the absence of smoke, light can easily reach the photodiode. If smoke particles are present between the light source and the photodiode, the amount of incident light will decrease and the detector will sound the alarm. Most smoke detectors work according to the indirect method. The light source and the detector are diagonally opposite each other. In the event of smoke, the light bounces off the smoke, causing more light to fall on the detector and sounding the alarm. An internally polluted smoke detector that works according to the direct method will, in principle, become increasingly sensitive and alarm.


  • Link to post
    Share on other sites

    Posted · Made a PLA smoke detector cap and it set it off

    Right, I'm aware of that.


    The cap should have no effect on it's function, which is why it's odd. 


    It was a one off, tried putting the same detector in and tried it with the same cap, nothing happened. Tried 3 other smoke detectors, nothing happened.


    People put blue tape, electrical tape, plastic bags, foil tape, etc. on these things and it doesn't set them off, but for some reason, this one time, it did for whatever reason.

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • UltiMaker Cura 5.3 stable released
        In this stable release, Cura 5.3 achieves yet another huge leap forward in 3D printing thanks to material interlocking! As well as introducing an expanded recommended print settings menu and lots of print quality improvements. Not to mention, a whole bunch of new printer profiles for non-UltiMaker printers!
          • Thanks
          • Like
        • 22 replies
      • Here it is. The new UltiMaker S7
        The UltiMaker S7 is built on the success of the UltiMaker S5 and its design decisions were heavily based on feedback from customers.
        So what’s new?
        The obvious change is the S7’s height. It now includes an integrated Air Manager. This filters the exhaust air of every print and also improves build temperature stability. To further enclose the build chamber the S7 only has one magnetically latched door.
        The build stack has also been completely redesigned. A PEI-coated flexible steel build plate makes a big difference to productivity. Not only do you not need tools to pop a printed part off. But we also don’t recommend using or adhesion structures for UltiMaker materials (except PC, because...it’s PC). Along with that, 4 pins and 25 magnets make it easy to replace the flex plate perfectly – even with one hand.
        The re-engineered print head has an inductive sensor which reduces noise when probing the build plate. This effectively makes it much harder to not achieve a perfect first layer, improving overall print success. We also reversed the front fan direction (fewer plastic hairs, less maintenance), made the print core door magnets stronger, and add a sensor that helps avoid flooding.

        The UltiMaker S7 also includes quality of life improvements:
        Reliable bed tilt compensation (no more thumbscrews) 2.4 and 5 GHz Wi-Fi A 1080p camera (mounted higher for a better view) Compatibility with 280+ Marketplace materials Compatibility with S5 project files (no reslicing needed) And a whole lot more  
        Curious to see the S7 in action?
        We’re hosting a free tech demo on February 7.
        It will be live and you can ask any questions to our CTO, Miguel Calvo.
        Register here for the Webinar
          • Like
        • 18 replies
      • UltiMaker Cura Alpha 🎄 Tree Support Spotlight 🎄
        Are you a fan of tree support, but dislike the removal process and the amount of filament it uses? Then we would like to invite you to try this special release of UltiMaker Cura. Brought to you by our special community contributor @thomasrahm
        We generated a special version of Cura 5.2 called 5.3.0 Alpha + Xmas. The only changes we introduced compared to UltiMaker Cura 5.2.1 are those which are needed for the new supports. So keep in mind, this is not a sneak peek for Cura 5.3 (there are some really cool new features coming up) but a spotlight release highlighting this new version of tree supports.  
          • Like
        • 22 replies
    • Create New...