This is based on Arduino. Four displays show the time. At the time a modified relay strikes a fire extinguisher which provides a bell-like sound. It has to be a CO2 type : powder or liquid types do not work.

It looks a bit Al-Qaedian, so be careful as to where you display it.

Also, fire extinguishers are under pressure so be careful not to hit them too hard.

The circuit board:

This is the clapper made with a modified relay :

This is the schematic : the circuit is intended to be connected to an Arduino board. The name on connectors are Arduino’s.

This is the sketch to be downloaded into the microprocessor: Fire extinguisher striking clock

And this is a video of the clock in action :

8 Responses to “A fire extinguisher striking clock”

  1. Ben Brockert says:

    Nice. I like the relay idea, cheaper than most solenoids and less likely to punch a hole through the tank.

  2. This just makes me want to do the same thing but put it on mock TNT sticks (made of aluminum to get the same sound effect)

  3. Erik Frank says:

    That’s a good one!

  4. Harvie says:

    Looks lika bomb huh…
    Put gun round between solenoid and fire distinguisher and it can be real one ;)

  5. Charlie says:

    Great project!

    You refer to the ‘relay’ but I’m having trouble finding the right parts, or maybe I’m just not clear on how you’ve modified it. Would you be willing to explain, or maybe just post a parts list?

    thanks!

    C

  6. admin says:

    What a relay is described here :
    http://en.wikipedia.org/wiki/Relay

    A general purpose relay (2-5 $) should do provided that the clapper can be glued to the moving armature.
    In the third picture from top, the greenish top PCB board is glued to the white moving armature of the relaly. When the coil of the relay is energized, the armature moves (and closes the electric contact we do not use) together with the greenish PCB.
    Hope this helps
    Alessandro

  7. Charlie says:

    Hey Alessandro, thanks! I actually meant what specific relay are you using, but a friend of mine hypothesized that it’s a standard “ice cube” type relay with the cover taken off.

    Anyway, cool creative hack. I’ll let you know if/when I get a slightly related project done/documented. Ciao!

  8. admin says:

    Ciao Charlie, now I understand : yes, it is a standard ‘ice cube’ relay with the cover taken off ! Never too late …
    Best
    Thank you
    Alessandro

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