# Flicker circuit for a pneumatic hangman ?



## House_of_horror (Aug 20, 2007)

Hello all,

I'm building a pneumatic hangman, that will be trigger by a PIR floodlight/110v solenoid. The problem is that I can't really use the 5 second test mode, otherwise, his legs will be standing up instead of shaking 

I tought of using a circuit like this hooked up to the floodlight socket.
http://www.supersoda.com/detail.php?id=00000000054

I don't want to blow up my solenoid, any ideas/suggestions?? I can't afford to pay and wait for a boobox or ready make system, I'll have to build it most likely.

Thanks for your help!!!


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## fritz42_male (May 5, 2009)

Purely depends on the current drawn by the solenoid. I wouldn't push more than 50-60 watts through a starter circuit such as this. That's about 0.5 amps. 

What does your solenoid draw?

Have you considered using some kind of DC motor with cam arrangement to get a more natural movement? You could power the motor off a wall wart connected to the PIR.


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## Restless Spirit (Oct 27, 2007)

Your solenoid isn't going to like that flicker circuit too much.
That circuit is designed for low wattage resistive loads like an incandescent lamp. Solenoids are inductive loads and don't take kindly to fluctuating power. Also when the power to an inductive load is removed, there's the collapsing field of electricity that can cause problems in other parts of the circuit.

Frizt42_male's idea my be a better option.


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## House_of_horror (Aug 20, 2007)

It's a SMC VQ2000 series solenoid, power consumtion is: Inrush 1.3 VA (12 mA), Holding 1.3 VA (12 mA)

So no worries on that side.

The hangman structure is already built, and mouvement is realistic. Here was my source of inspiration: http://www.scaryguys.com/kicker.htm

I guess I will give it a try this weekend and see the result


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## DarkShadows (Feb 6, 2006)

Id just spend the 40 bucks and get a prop-1... You get alot more control over the prop


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## Haktup (Sep 29, 2009)

That is almost exactly what I building this year I however am using a window wiper motor to actuate the legs. 12 volt dc and easily had from most junk yards.


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## fritz42_male (May 5, 2009)

House_of_horror said:


> It's a SMC VQ2000 series solenoid, power consumtion is: Inrush 1.3 VA (12 mA), Holding 1.3 VA (12 mA)
> 
> So no worries on that side.
> 
> ...


12mA probably wouldn't be enough draw for the bimetal setup inside the starter to flicker. I'd suggest hacking a flicker tea light instead - use the output from the tealight to drive a Triac to switch the 110V supply (I assume it's a 110V solenoid). Do a search on here as there was some discussion about this a while back - I think Otaku had a circuit. If not I could probably draw something up.


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## Otaku (Dec 3, 2004)

HoH,
Fritz42 mentioned the circuit I drew up for using a tea light output to drive multiple LEDs, but it's a low-voltage DC circuit. It uses a Darlington array to switch the power for the LEDs, and that won't work for your application. The fluorescent starter flicker circuit may work, but again, fritz42 is correct about the load possibly being too low to get the starter to pull up.
A suggestion - one of the Lightning F/X boxes with a CD or MP3 player would work to power the solenoid. The F/X box switches AC and if you make a sound file that has random loud sounds on it, the F/X box will send AC to the solenoid just like it powers light bulbs. If the F/X box is located near the prop, you can use the other side of the stereo sound file to provide sync'd grunts and choking sounds coming from the poor slob on the end of the rope. I know you've seen this before, but here's a link:
http://www.thingsyouneverknew.com/p...tivated+christmas+tree+lights.do?WT.svl=83002
Just might do the job...


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## fritz42_male (May 5, 2009)

At Otaku suggested, you could buy a simple sound to light board like this one and use one of the speaker outputs to drive it or use a flicker candle to drive it. Simply desolder the LED off the flicker candle and take the outputs to the sound-in connector.

http://www.electronics123.com/s.nl/it.A/id.354/.f?sc=8&category=39

Then instead of lights, just drive the solenoid.


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## craigsrobotics (Oct 12, 2009)

*Solenoid valve...*

You need to check the response time of your valve....that flicker circuit voltages fluctuate, which valves don't take nicely to....and the valve may not respond fast enough to actually open the airway....changing supply voltages quickly to a coil over a period of time may result in pre-mature burnout.


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## Otaku (Dec 3, 2004)

Craig is correct on the voltage fluctuation from a tea light flicker circuit. I measured anywhere from 2.2 to 3.6 VDC while testing the multi-LED driver circuit. I still think the light organ, driven by a random sound file, would be the best bet for controlling the solenoid on the cheap. If you're interested in the multi-LED circuit, here's a link to the thread:

http://www.hauntforum.com/showthread.php?t=17685&page=2


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## fritz42_male (May 5, 2009)

Or a picaxe board linked to an SSR. I'm just building another timer version but this time for a random flicker.


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