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Automatic fire suppression?

hazmatt99
(@hazmatt99)
Trusted Member

Hello! Just wondering if i can get some advice setting up some cheap automatic fire suppression for my printers. I'd like to avoid setting up octoprint right now because limited brainpower but I will if I have to. Lemme know if there's something effective and user friendly I can buy.

I have TRONXY XY-2 pros in case that matters, heard there might be something firmware related to shut the machine down if there's thermal runaway detected? Not sure if I have that.

Thanks!

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Topic starter Posted : 28/09/2021 7:34 pm
Luke
 Luke
(@lmf5000)
Expert Moderator

Hi Hazmat!

For automatic fire suppression, I've seen a couple of spherical heat-sensitive powder extinguishers, like this - https://www.elidefire.fr/home or this - https://www.amazon.com/Automatic-Extinguisher-Mounting-Bracket-Suppression/dp/B074KZDNKY/ref=sr_1_1?dchild=1&keywords=fire+ball&qid=1632855529&sr=8-1

(NB: I haven't tried one personally, but from the videos I got the idea that one could be mounted above the printer, perhaps from the top member of the frame, and it would burst and spray the powder all over the printer if it caught fire).

Of course there's no guarantee that it will put out an electrical fire if the electrical supply is still operational and generating heat, so for that I strongly recommend a smart plug that you can disable remotely from your phone - I personally use this one: https://sonoff.tech/product/smart-plug/s26/ but there's a huge selection that will do fundamentally the same thing.

Last thing you need is a way to look at your printer remotely, to know when to pull the plug. I used to use a webcam connected to my desktop, running Yawcam to show the feed from the webcam, and remote in from my phone using TeamViewer or Google Chrome Remote Desktop... but these days you can get relatively inexpensive 360° security cameras that will let you monitor live on your phone and even look around the room, and listen and talk through the camera. Here's the one I use (about $60) - https://www.mi.com/global/camera-360/ . Again, lots of different models to choose from that will do the job ;).

A note about the firmware protection - those are all great things to have, but will not protect against every eventuality. If the firmware crashes, the protetion might crash with the firmware. If the MOSFET powering the hotend gets stuck in a conductive state, software won't be able to stop it from melting your hotend and possibly starting a fire with the plastic in the nozzle. If the power supply short-circuits, no kind of software will be able to stop the fire, and if it's a mild short it may be enough to ignite the insulating of the wiring but not enough to pop the fuse in the plug or in the supply - which is why you should actively monitor your printer and kill its supply if anything is wrong.

To slightly automate that a little more, some smart plugs or smart switches have power monitoring. In theory you could set an upper limit beyond which it will assume the worst and cut power. For instance, my CR-10 mini draws up to 330W max (all heaters on). So if it suddenly draws say 450W it's probably safe to say that something's not right. I use this power-monitoring smart switch which can perform this function - https://sonoff.tech/product/diy-smart-switch/powr2/ (you have to wire it to a plug and socket yourself if you want it to be usable for any appliance around the house, or you could cut the printer power cable and wire it inline but then you'll only be able to use it with your printer or anything that uses the same cable). However, I haven't actually tested it in this kind of usage because of concerns that it will false-trigger and ruin a long print - I just wanted to make you aware of this possibility 🙂

You might want to look into a WiFi-Equipped smoke detector too to warn your phone in case a fire is detected. I don't have one personally, but I did find this one that looks like it will do the job - https://www.theverge.com/circuitbreaker/2016/5/4/11593448/roost-smoke-detector-alarm-connected-battery

Based on how reliable it is, you might be able to use an automation app like IFTTT to automatically kill the printer (via the smart plug) if the smoke detector goes off. Obviously you'll want to thoroughly test the smoke detector for false alarms before trying that though!

Hope this helps! Let me know what you think!

 

Regards,
Luke

ReplyQuote
Posted : 28/09/2021 8:16 pm
hazmatt99
(@hazmatt99)
Trusted Member

I forgot to subscribe to this so I didn't see the response lol. I'll look more in depth at all of these when I get back to work but it already sounds like octoprint with some cheap webcams is gonna be the cheaper option lol. Or at least it won't cost that much more but opens the door for more functionality in the future.

I have seen the fireballs that release the fire suppressant on the interwebs, partly that's what caused me to asked because from what I've heard it just causes more of a mess than actually solve any problems. Like the chemical inside is garbage and it goes EVERYWHERE not just where you need it.

Anyway I'll get back to this in a bit, thanks for all of the info this is a fantastic place to start.

ReplyQuote
Topic starter Posted : 05/10/2021 5:50 pm
hazmatt99
(@hazmatt99)
Trusted Member

Ok this is good stuff. So a camera and a smart plug is definitely a good start. For the fire aspect i actually totally forgot that my apartment complex uses something similar to the fire ball for kitchen fires, but its about the shape of a tuna can. They both activate only in the presence of a fire but the difference is the tuna cans spray straight down, and they're cheaper you can get 2 for the same price as 1 ball, and i think some brands attach magnetically.

Tbh now that im thinking about it im less concerned about running it overnight. If a fire starts my smoke detectors will probably catch it and I have extinguishers.

I do wish i could just buy a smart plug with a thermistor or something. Don't need to think about rigging up or programming something just plug it in a trip a breaker when the thermistor reaches a certain temp or if some kind of sensor detects a fire.

I did find this guy tho https://www.kidde.com/home-safety/en/us/products/fire-safety/safety-accessories/auxiliary-devices/sm120x/ its a relay connector so if you have a wired smoke detector (or maybe thermistor?) And a relay enabled power strip like this https://www.amazon.com/gp/product/B00WV7GMA2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 you should just be able to put them together and then when the detector activates the power switch activates. Maybe i'll put in the time to figure that stuff out.

 

ReplyQuote
Topic starter Posted : 05/10/2021 7:19 pm
Luke
 Luke
(@lmf5000)
Expert Moderator

Hi Hazmat,

Correct - octoprint will open up a lot more possibilities than just a standalone camera since you can use volumes of add-ons to do a lot of things (some even detect when the print turns to spaghetti and automatically warn you or halt it).

And yes, powder extinguishers generally make a huge mess when they go off. It's safe to say that any office equipment in the vicinity of the printer (like computers) will probably be destroyed by the extinguisher. All things considered though, it's better than a full-on house fire especially if buildings are constructed of wood in your country (in our country buildings are made of limestone and cinderblock, so fires tend to be more self-limiting since the walls and ceiling themselves are pretty much non-flammable).

In theory your idea of the relay and the extension could work, but you'd have to test it well. You don't want nuisance false-detections that kill your printer mid-print ;). That extension seems like a great find actually!

 

Regards,
Luke

ReplyQuote
Posted : 05/10/2021 9:27 pm
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