Light Emitting Border tutorial

[~arph]

I use a dremel too:

Wear goggles and old clothes.

...seriously

[CodeMonk]

I use a dremel too:

Wear goggles and old clothes.

...seriously

And one of those dust covers for your face. double seriously

[chicago_mike]

What thickness plexi do you guys use?

[Arn C.]

I am using 1/4 inch plexi.  I have tried thinner but I like the 1/4 inch better. You can bury most of the led in the 1/4 inch.

Arn C.

[sleepybrighteyez]

Ooooooooooh...

Very nice. Very, very nice. How hard would it be to get the plexi LED to vary in brightness based on the guitar signal? Would it be as simple as putting the LED in series with the audio signal path, so varied voltages coming from the guitar vary its brightness? It would be killer to have all my pedals visually reacting to my playing. Bwahahaahahahah!

[CodeMonk]

2 questions about this process....

1.  Where does one find plexiglass?  Would the average super-hardware store (ie Home Depot) carry it?

2. How hard is it to cut?   Does a Dremel work well for the task?

Thanks
-Chris

Dremel works fine for fine tuning the size
I did this too.
What I also did was rough cut the plexi, then did the screw mounting holes, then wrapped duct tape around the box.
I then trimmed my plexi with a dremel cutting wheel, and one of the barrel sandng whees. and it turned out fine.  The plexi didn't melt signifcantly, just some of the small bits that came off became really warm and soft.  Nothing liquid.

[~arph]

Ooooooooooh...

Very nice. Very, very nice. How hard would it be to get the plexi LED to vary in brightness based on the guitar signal? Would it be as simple as putting the LED in series with the audio signal path, so varied voltages coming from the guitar vary its brightness? It would be killer to have all my pedals visually reacting to my playing. Bwahahaahahahah!

You'll have to build something called an envelope follower. The signal from the quitar itself is to weak.
A good simple follower for this can be found for example in the nurse quacky (the bottom part of the schematic)

http://www.home-wrecker.com/nurse-quacky.html

[Uma Floresta]

This is just about the coolest thing ever as far as visuals go.

[sleepybrighteyez]

Have you guys seen the acrylic sheets that are supposed to be a replacement for glass? I seen them for the first time this weekend and I wondered if they would work just the same as the plexi-glass used in this project.

[frank_p]

Have you guys seen the acrylic sheets that are supposed to be a replacement for glass? I seen them for the first time this weekend and I wondered if they would work just the same as the plexi-glass used in this project.

Do you have more info ?  Plexiglass is an acrylic plastic (Polymethyl methacrylate) and is commonly callec acrylic glass.  You may be refering to the same material.  Depending on the type of acrylic and mean molecular weight, acrylics can have very broad tolerances on mechanical specs.

[The Tone God]

Be aware that sometimes the term "plexiglass" is used for polycarbonate which is another product.

Andrew

[frank_p]

Be aware that sometimes the term "plexiglass" is used for polycarbonate which is another product.

Andrew

True, i've seen it also ( but not too clear in my mind (not a word game) ).

Anyway, take in account that acrylics is much more prone to crack while making holes, cutting, kicking, etc...
Polycarbonate is very impact resistant and not prone to cracks propagation.  Should also be much more $$$.

[The Tone God]

True. On the flip side acrylic tends to have better optical characteristics in particular cell cast acrylic although in this case that may not be as important so even extruded should work fine. Also IMHO acrylic tends to have less scratch build up. Polycarbonate tends to collect fine scratches to the point that it starts to make the view milky or cloudy. Once again it may not be much of an issue in this application.

Just a few thoughts.

Andrew

[frank_p]

Just a few thoughts.

But still important in my real work !

[sleepybrighteyez]

The next time I hit up the hardware store I'll check it out some more. All I remember is that the 'acrylic' is shatterproof, etc.

[cpnyc23]

If you were to scratch the surface (top and bottom) of the plexi... across the whole thing, would that help reflect light better and direct it to the borders?

-chris

[frank_p]

If you were to scratch the surface (top and bottom) of the plexi... across the whole thing, would that help reflect light better and direct it to the borders?

-chris

No, directing the light on the borders are based on refraction (like in optic fibers).  If you scratch the surfaces, part of the light will be redirected in the box and less light will go on the edges. 

http://en.wikipedia.org/wiki/Refraction

[Fl!P]

I have an idea:

How about putting reflective material on the top and bottom of the plexi instead of scratching it then.
Something like, say, gluing on aluminum foil?

[frank_p]

It's better to leave it like that.  The interaction between air and the plastic makes it good.  You would have to put a very reflective thing, like chrome deposition.  Too much trouble for not much gain.  IMO

[frank_p]

If you were to scratch the surface (top and bottom) of the plexi... across the whole thing, would that help reflect light better and direct it to the borders?
-chris

No, directing the light on the borders are based on refraction (like in optic fibers).  If you scratch the surfaces, part of the light will be redirected in the box and less light will go on the edges. 
http://en.wikipedia.org/wiki/Refraction

Excuses.  Refraction is what is happening before attaining the critical angle.  Then past this angle, you have total internal reflection.  Been a while since I've done optics. 

So if you scratch the top and bottom you augment the quantity of light that will go outside of the plastic because you augment the area where the angle of incidence of the light will be less than the critical angle.  So it will go out with an amount of refraction before attaining the edges.

http://en.wikipedia.org/wiki/Total_internal_reflection

You see that you can't see through the surface of the water when you look past the critical point.  Its like if the LED would be the turtle.