Halloween Forum banner

1 - 20 of 565 Posts

·
Bête noire
Joined
·
2,631 Posts
Discussion Starter #1
I'm starting this thread to allow Mr. Grimsley's "Dead Ringer" thread to get back on track. His idea for a ringing coffin bell evolved into a brainstorming session on how to create glowing and fading "footsteps" walking around a graveyard. I like Grimsley's concept and it needs to keep going in it's original location. So, with that said -

Long story short, I came up with a LED chasing/fading circuit based on a cheap board that's available at All Electronics. After working with it for a while, it was obvious that many new parts and some hacking would be needed to get this effect to work reliably. By the time you got done, the cost would be around $25 - $30, not including the LEDs, the wires, and a control system (555 timer circuit or similar) to turn the thing on and off.
I had been in touch with Jeff at Simple Circuit Boards to get some advice on an auto-shutdown method I was working up, and he mentioned that he could do this effect using a PIC-based circuit. He sent me a layout of the prototype and I think it looks very good. Easy to trigger, shuts off automatically after lighting and fading LEDs 1 through 10, and no assembly required except for the LED wires. The user would supply the current-limiting resistors (value dependent on the chosen LED), the LEDs and the wires. And, of course, the feet. He and I are tossing some details back and forth at this point, but he should have pricing info available very soon. Jeff could also supply the LEDs and wires for an additional price.

More to come...
 

·
Bête noire
Joined
·
2,631 Posts
Discussion Starter #3
I'm very interested in this project...keep us updated, Otaku!

When you say we would have to provide feet, what are you thinking of (I mean, I've put a lot of myself into my props before, but...:p)?
LOL! That would be the acrylic "footprints" that the LEDs light up. I know what you mean, I'm lucky to not have left some appendages in my props, too.

I'll update as I get more info from Jeff.
 

·
Bête noire
Joined
·
2,631 Posts
Discussion Starter #5
You got it, Mr. C. If you were usng 1/8" sheet you'd need to use T1 (3mm) LEDs. For a 5mm LED you'd need 1/4". The LED should probably go in the heel of the footprint, but the best location is still being looked into.
 

·
Registered
Joined
·
71 Posts
Let me start by saying I'm a big fan of Jeff's stuff and have been using it for years.

If you can live with a max of 7 footprints, an alternative would be a Prop-1 from EFX-Tek. The cost would be $40.

I'm sure that the guys at EFX-Tek would write the program if you need it.

Otherwise, it seems to be a simple program to write. Watch for the trigger event, pwm the lep up on the first step, pause, pwm down..... rinse and repeat for each step. The advantage to the Prop-1 is that you could adjust how long each foot step took and how fast the footprint fades in and out based on your preferences and condtioins.

With the ULN onboard to handle current you can drive several LED's per footprint.

Just and alternate idea

SteveC/ScaryTinker
 

·
Bête noire
Joined
·
2,631 Posts
Discussion Starter #8
1/4" sheet with a 5mm LED only gives about 1/16" of acrylic around the LED. Do you think that's enough?
My first thought was the heel, too, but I think you'll get more even lighting if you put the LED on the side of the foot.
Sure, plenty of room, but you'll need to pretty handy with your drill. Low speed, slow feed - acrylic melts easily when drilled. The best location probably will depend on the LED. A clear-case LED will have a more focused beam and will project further into the acrylic.
 

·
Registered
Joined
·
94 Posts
an idea...

what about phosphorescent painted footprints along and blacklight system that would travel along the prints? just a thought...
 

·
Registered
Joined
·
275 Posts
I would also be interested in the leds and wiring. If i can avoid using a Prop1 on this, that would be a good thing. I have too many other things that need my beloved microcontrollers. When Otaku gets this sorted out with Jeff, I think it will be a no-brainer to just purchase this prop as a plug and play. By the way, I tried lighting footsteps(3/16's) with an ultrabright led and it does in fact look and work best from the heel area. It could however use more light. It is quite bright at the heel but fades rapidly after the arch/instep area. I don't like adding more led's to it. They really don't work well with the idea that these are glowing residual aftereffects of a ghost walking. I am still looking into UV reactive plastics. They might just be the ticket for the best "glow". Problem I see is how to hide the edges of the plastic. They appear to glow the most. Maybe black paint. Here's a little article I found on plastic and UV. Doesn't explain all, but sure seems to be something to pursue. UV Penetration and Plastic
 

·
Banned
Joined
·
3,040 Posts
Regarding the LED method,

I seem to remember a youtube video...can't find it at the moment...that dealt with spreading the light source evenly; with just one LED. in the video the clear plastic was slightly scored/cut with a dremel tool. The evenly spaced cuts/scores helped to spread the light source evenly. It also used reflector tape...Could this work for the ghostly footprints?

*I found the youtube link www.youtube.com/watch?v=0JSMQk61xQ8]
 

·
Bête noire
Joined
·
2,631 Posts
Discussion Starter #14
One of the ideas for spreading the light was to buff the surface of the footprint with fine sandpaper or a scotchbrite pad. I plan to test this when I get a chance. It may solve the light spreading issue without havng to add LEDs to the mix.
Using UV LEDs with reactive plastic is interesting, as well, but UV acrylic can be costly. A coating of Clear Neon UV paint would probably light up very well, but might interfere with the fade effect because the paint will have a residual glow. The fade effect works best if the footprint disappears quickly, IMO. Lots of good ideas are being posted here - keep 'em coming!
 

·
Bête noire
Joined
·
2,631 Posts
Discussion Starter #16
I wonder if a fluorescent light diffuser panel would work. They usually have one side flat and one side faceted for spreading the light. Bond two panels together to get the thickness you need to mount an LED. These things get tossed out regularly so the cost is nil.

Dave, do you have any pics of the effect?
 

·
Funeral Crasher
Joined
·
7,445 Posts
That's a good idea about using flourescent light panels. My problem would be trying to cut the shapes out of them without them cracking.

I don't have any pics, but I was going to try to take some tonight. I coated a piece of plexiglass with liquid laundry detergent. I'm letting it dry and I put together a UV LED circuit to try on it. If I can get pics I'll also take pics of the green and blue LEDs also.
(My digital camera is pretty cheap--For dark pics I usually have to manually edit them on the computer to brighten them back to how bright I remember them being.)
I'll post whether it works or not.
 

·
Funeral Crasher
Joined
·
7,445 Posts
OK--I took some pics of the effect on a piece of plexiglass about 5 inches long, 2 inches wide. Surprisingly enough light was put out where I didn't need to edit the pics any.
Using a UV LED with laundry detergent on the glass didn't seem to work for helping it glow. Just diffusing the plexi with some sandpaper seemed to help a lot more. Maybe the clear UV paint would work better?? The blue LED is rated at 7000 mcd. I'm not sure of the rating of the green one. Also the plexiglass I'm using here is only about 1/16th of an inch thick. It seems like the green LED with the sanded (diffused) plexi gives the best glow.

Here's a pic of the UV LED on clear plexiglass:



Here's a Green LED on clear plexi:



Here's a blue LED on clear plexi:



I then sanded the same piece of plexi to diffuse the light.

Here's the UV on sanded plexi:



Here's a Green LED on sanded plexi:



Lastly is the Blue LED on sanded plexi:

 

·
Registered
Joined
·
139 Posts
more expensive but....

I did an effect like this about 2 years ago, and I used a video projector hidden up in a tree, to project the ghostly footprints down to the graveyard grounds. I realize LED's are cheaper than a projector and video production time, but the result was killer!

Bill.
 

·
Bête noire
Joined
·
2,631 Posts
Discussion Starter #20
Dave - Thanks for the pics, they're very instructive. It looks like you could use either sanded or non-sanded plexi, depending on the effect you want. I like both effects, but the sanded plexi would probably be better if you were using scrim to hide the unlighted footprints.

I've heard from Jeff, and he has a PIC-based design that will light and fade 10 LEDs sequentially. The board is triggered by a dry contact, and will shut down after one cycle. The LEDs, current-limiting resistors, and wires for the LEDs are provided by the user (see below).

Here's what Jeff says:

"The LEDs (wires to) are attached by screw-down terminals. There is one pot to control the rate. It is actually controlling the fade rate which, in turn, controls the overall rate. The LED sequence happens like this. LED1 comes on for one second. LED 2 then comes on and then LED 1 fades out at the rate determined by the pot. When LED1 has faded out, LED3 comes on and LED2 fades out. This way, there is always one "foot" on the ground."

He can provide the board for $36, assembled and tested. I don't know if this price includes shipping. Given that the cost of DIY comes in around $30 (buying parts at AE) this looks pretty good to me. Jeff can also provide wired LEDs for an additional charge. You can contact Jeff at [email protected] or at his website - Electronics.
 
1 - 20 of 565 Posts
Top