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Help With A Timed Delay Switch

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Fallen

New Member
I need some electronics for a magic show, but unfortunately all I really know is that you need to form a circuit to make things work.

For the show, I need to press a secret button, which makes a circuit with the device and a 12volt battery,, and of course activates it (easy enough, even for me).

Now the hard part is, I'd like it to turn itself off/break the circuit after 15 to 30 seconds. Ideally I'd like some kind of countdown timer which I can put in between the switch and device, which automatically disconnects itself 20 seconds after a charge starts going through it.

If anyone could give me any advice it would be appreciated, although I should mention again that I really know very little about electronics, so I might not understand a lot of common terms, ect.
Thanks :)
 

MikeMl

Well-Known Member
Most Helpful Member
What type of load does the device supply while it is ON? Voltage/current?
Do you want it to shut itself off completely (so it doesn't drain the battery even though the load is off)?
 

Fallen

New Member
It's a tiny device that makes smoke powered by a 12 volt battery. Unfortunately it doesn't give any info about the current or such, however I'll try to contact the creator and ask.

Also it's fine if the battery is still being drained.
Thanks
 

MikeMl

Well-Known Member
Most Helpful Member
I need to know how much current the smoke generator draws to know how to size the battery, and the switching device that turns it on/off.
 

Fallen

New Member
Gah sorry, that should have been powered by a 9 volt battery, not 12. For the switch I was just going to get a standard toggle or rocker switch - basically any will do so long as it's quiet and easy to press. I still had no luck finding out the current though sorry.
I
'm been looking at some different products, and was wondering if something like this might do the job? https://jaycar.com.au/productView.asp?ID=KJ8202


Another thing I was considering is would it be easier to have a remote control set up of some sort? I've seen quite a few different types for sale, but I don't know if it's just a matter of soldering two wires and then it's done, or if it's more tricky than that.
https://jaycar.com.au/productView.asp?ID=KV3570
 
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MikeMl

Well-Known Member
Most Helpful Member
Here is a circuit that takes a momentary button push [V(On)], and then powers the smoke generator for ~20sec[V(Out)]. The 555 draws a few mA, so you will have to disconnect the battery to prevent it from running down the battery while not in use. The 555 is capable of switching about 200mA, so if your smoke gen requires less than that, it should work. If you need more current, I can add a power switch between the 555 and the load.
 

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