IN DEVELOPMENT Fire Protection

Discussion in 'Guides, Mods, and Upgrades' started by Dr Jeep, Nov 21, 2016.

  1. Dr Jeep

    Dr Jeep Well-Known Member

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    This started as a conversation about machines left running overnight and the associated risks. My machine is pretty much exclusively run unattended overnight and although it's in an outbuilding I started to wonder if there was a fire (or at least lots of smoke damage) risk from leaving it unattended.

    I still think the risks are pretty low, but for the sake of a smoke alarm and a few bits of electronics I had kicking about I thought it might be fun to build a fire alarm cutout device.

    Pretty much this device will sit inline and powered by the mains lead going to the BigBox. A standard smoke alarm with a relay output triggers the device to cut power to the printer via a spark-less solid-state relay.

    You can use either the type of low voltage smoke alarm designed to be interconnected (as per the box in the picture I'll attach in a moment) or if you prefer you could use a smoke sensor designed for a fire alarm panel.

    It also doubles up as a standard smoke alarm when the BigBox isn't in use and as a more convenient to access power switch/emergency shutdown button.

    Life keeps getting in the way so progress is glacial...So far I have built a little Bistable switch on a front panel PCB, mounted a little off the shelf 12v PSU and found a suitable off the shelf relay and smoke alarm.

    The bistable switch uses a 555, but if you want to build it out of a few transistors (or even one transistor if you are clever) instead that would do equally well, I just happen to have 555's kicking around with no use for them at the moment so I used a 555 :)

    Diagrams and a printable case design will appear once I have it finished and all working well. Usual caveats about working with Mains voltages apply.
     
    Ephemeris and Paul Begley like this.
  2. Dr Jeep

    Dr Jeep Well-Known Member

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  3. Dr Jeep

    Dr Jeep Well-Known Member

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    Probably worth pointing out that there is an even simpler way of doing this with just the smoke alarm, power supply and a DPDT relay. But I didn't want a spark gap on a fire alarm type device (as if there are leaking gasses as as result of the fire then the alarm itself could cause a gas explosion).

    Also if you use the same workshop for dusty stuff then consider the ionising type of smoke alarm not the optical type I bought.
     
  4. Stigern

    Stigern Well-Known Member

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    I used a smoke alarm module from ebay, and a nexa remote kit. Just hooked up the remote to the smoke alarm module. And attached one remote-socket to each printer.
     
    #4 Stigern, Dec 3, 2016
    Last edited: Dec 3, 2016
  5. Dr Jeep

    Dr Jeep Well-Known Member

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    Hmm nice solution, I wanted something a bit more hand-built than that but your way certainly is a neat way of doing it :)
     
  6. Dr Jeep

    Dr Jeep Well-Known Member

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    Just some wiring to tidy, a lid to print and it's done.

    [​IMG]
     
  7. Stigern

    Stigern Well-Known Member

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    Now that looks way better than what I did hehe.

    Great work :)
     
  8. Dr Jeep

    Dr Jeep Well-Known Member

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    Thanks, it's not going to win any awards for industrial design....but it'll do the job well I think. I'll put up a schematic and some links to the design files in case anyone fancies building one, but there is nothing revolutionary here...just a bistable circuit (of any kind) a PSU and a Solid State relay.
     
  9. Dr Jeep

    Dr Jeep Well-Known Member

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