LED and plexi panel

[BigThumbToe]

Question for you guys, for my control panel, I'm wanting to etch plexi and then use LEDs around the edges to light it up. I already have everything designed as far as the etched image and layout goes. At work we have a CNC router that Ive run some tests with and have had some pretty good results so far dealing with small scale. the things a beast and a beauty.
http://www.multicam.com/eng/Products/5000series.html
Heres where Im stuck. I havent figured out a way to get the LEDs around the edges so the whole design gets an even amount of light. The LEDs have to be hidden and in a way where they wont get damaged. at work we carry 1/8, 3/16, and 1/4 thinkness plexi/lexan. Ive thought about going with the 1/4 and drilling holes in the side but ive cracked it almost everytime ive tried that. Is there a safer way of doing this? Im open for any other ideas about LED placement.
Thanks

[Franco B]

I'm not surprised you cracked the plastic drilling into the side. It is possible but you would need to get your feeds/speeds correct and the material would need to be held securely at 90 degrees to the table and central to the center of the material which on the whole could be tricky due to the likely height of the material.

If you did end up going down that route you would want to use 3mm LEDs and the Lexan (Polycarbonate) rather than the Plexiglass (Acrylic) as Polycarb machines much better in this type of application. However if you did use Polycarb for your CPO it would scratch much easier than Acrylic as it isn't as scratch resistant. I personally wouldn't recommend using Polycarbonate full stop for a CPO.

Seeing as you have access to a CNC router what I would suggest is to make a coloured bezel for the CP to hide the LEDs underneath. You could then make the inner clear CPO with the exact same profile as the bezels inner profile.

The bezel would want to be thinner than the CPO so the LEDs can shine through the material. I would suggest using the 1/4" clear for your inner and the 1/8" for the coloured bezel.

I think this would look nicer as you would not actually see the LEDs at all.

I can knock up a drawing later if it would help to visualise it.

Just my £0.02

[Kman-Sweden]

You could just flatten the top of the LED and mount it pressed against the edge of the plexi.
Can't wait to see the final product.

[BigThumbToe]

i think i have a rough idea of what youre saying Franco but a pic sure would help lol

[drventure]

I've seen that done before. Use a heating iron or something to flatten out the rounded top of the led, when you do that, it no longer has that focusing "lens" effect and the light spreads out much better, so then glue that (using some kind of transparent glue) to the edge of the plex to "light up" the whole plex panel. Actually, you might even be able to just glob hotglue over the entire led to "fix it" in place around the edge of the panel, then cover that with some kind of molding/lip.

But if you want the plex to go right up to the edge of the panel, that'll be more difficult.

What you might do in that case, is cut some sort of "design" out of the middle of the panel, mount the leds there pointing OUT toward the edges of the panel, and then cover the hole with a decorative plate of some kind (personally, I like brass  )

[Franco B]

i think i have a rough idea of what you're saying Franco but a pic sure would help lol

Ok, imagine this is your CP



Design your CP profile how you want it. I have used a 15mm wide bezel in this case. CNC route the outer profile of the black bezel and then CNC route your inner clear acrylic using the inner profile of the bezel.

This is a side view of the panel:



The light blue is your clear 1/4" Acrylic, the black is the 1/8" Acrylic bezel and the brown is the MDF. The darker blue is obv the LED(s).

CNC route the MDF to the same profile as the bezel and then counterbore an 1/8" recess so that the two pieces sit flush and also route a groove for the LEDs to sit in.

If you didn't want the appearance of the acrylic bezel you could get some simple graphics accurately cut for it since you will be working of a dimensioned drawing.

[BigThumbToe]

ahh yes, i had a similar idea awhile back. didnt think of using a second piece of plex though.
i do have a trackball. you think maybe i could run some LEDs from under the mounting plate? that might look too tacky with the plate on top of the plex though. unless i have the plate flush with the top piece of plex 
for the LEDs i was thinking of just using grooveygamegears RGB-Drive module and then running them with my LEDwiz. know of anything better to use? the module looks like its going to cause problems with placement...

[Franco B]

If I was you and I was LED lighting an etched panel I would use a trackball that doesn't have a mounting plate on top. If you do you will be losing a lot of the area that you can etch plus I think you could etch a nice design/patten in a circle around the trackball. Trackball mounting plates are hideous too IMO.

Yeah I think you would struggle to get RGB drives in there and to be honest they are not really designed for that kind of purpose anyway. You should be fine with 5mm common anode LEDs though.

I really think you should do this, I think it could look pretty nice. 

There have been a few other projects with etched CPs, I'll see if I can dig them up.

[BigThumbToe]

Im still learning about LEDs. could i use a common RGB LED with my LEDwiz?

[Franco B]

Short answer, yes. You would want common anode LEDs.

Long answer:

A normal single colour LED has two terminals called the anode and the cathode.



The anode of a device is the terminal where current flows in. The cathode of a device is the terminal where current flows out.

The anode is connected to the power source and the cathode is connected to ground, often with a resistor between the LEDs cathode and ground.

This is an RGB LED:



As you can see there are four leads coming of it. If it was a common anode there would be one lead that is positive where you connect your power supply to and then there are three separate red, green and blue cathodes that you can independently connect to ground.

If it was a common cathode RGB LED there would be one common cathode that would be connected to ground and each red, green and blue lead would have its own power supply.

For your LED Wiz you want to use common anode RGB LEDs. You feed the LEDs anode power from your LED WIz and then each of the red green and blue cathodes is connected to the numbered terminals on the LED Wiz, usually with a resistor between the cathode and the terminals.

Hope that helps a little.   

[BigThumbToe]

Yes thank you that help a lot! If i have the time tomorrow I'm going to run down to radioshack or Frys and pick some stuff up. Ill try to get some pictures or videos of some of my tests