# Fading Cheshire cat grin



## deadSusan (Jun 26, 2013)

I would like to add a bit of whimsy to a forest setting, so I was thinking of a fading Cheshire cat smile. I've started going through some threads about dimmer switches, but if anyone can steer me in the direction of how I would go about setting this up, it sure would be helpful.


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## RoxyBlue (Oct 6, 2008)

Hmmm, I'm wondering if this could be done with a pepper ghost set up.


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## deadSusan (Jun 26, 2013)

I didn't think about a projection. Hmmm.....I'll have to think about how I would set that up. Maybe one of those digital picture frames might work. 
Thanks Roxy.


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## corey872 (Jan 10, 2010)

Seems there would be several ways to do this, depending on how you attempt to achieve the effect.

If you use a projector I would worry internal circuitry might try to keep the lamp at the same brightness as you lower the voltage. As you near some low volt limit, you might get erratic operation such as flickering, or the lamp/projector just winking out all at once. In this instance, you might need some type of mechanical shutter to slowly close in front of the lens.

If you intend to use some type of mains / 120V bulb...possibly illuminating something from inside?... then we might be able to recommend some type of circuit depending on how complex you want the dimming to be.

If the prop can run off batteries and LED's (or low voltage power), I have a circuit sketched up (somewhere!) which gives you control of fading or 'breathing' LEDs. You can control fade in, fade out, etc. Basically a board version of this circuit:


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## corey872 (Jan 10, 2010)

...guess we were typing at nearly the same time!

If you're looking at some type of picture frame, you might also consider a computer monitor. I used to have a display years ago which ran on 3 computer monitors. It was a very old / low power computer (ie single 333MHz AMD processor... if that means much) and the monitors were 800x600 resolution. But all you need is enough power to run a slide show program, a screen saver with your custom images, or perhaps a simple movie loop, depending on the effect you want.


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## deadSusan (Jun 26, 2013)

Thanks corey872. It's funny you should mention the monitor because I was looking at those too. I like the idea of a screen saver. 
You have given me a few ideas to think about. Thanks again.


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## alewolf (Nov 5, 2012)

If it was video, could you not just have it fade in the actual footage and set the same background color as to the location of the projection. Minimum hotspot and a fading grin... No reasn to lower voltage at all. To me that would be the easiest. 

Another thought, some colors will glow under the right light combos, but vanish unter others. You might be able to paint in on and use some of those spots that are programable. I have two and they will do fades etc... thus the smile would be stronger and then weeker based on the brightness of the spot. As a Kid we would draw things on our arms etc.. and play with different light colors. Read it in a kids book on making monster magic.


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## Otaku (Dec 3, 2004)

Several years back I built an AC pulsing light circuit, it runs about 8 seconds from bright-to-dim-to-bright again. This may be too fast for what you have in mind, and the other thing is that it runs continuously. There are some Xmas light faders around that can be adjusted to run a slower cycle, but again they run non-stop. Here's an example (out of stock, though )
http://www.christmaslightshow.com/2-Channel-Fading-Light-Controller.html


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## BillyVanpire (Apr 22, 2015)

using a simple motor you could make a wheel spin to make the face visible, then disappear. 
or print a gradient from light to dark on paper to make it fade in & out as the wheel spins?

something like this by hollywood haunters






i think i would create a video loop or gif to play on a digital frame.


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