My son was showing me a new logo he had designed for his music endeavors - Single Alien Theory and I was looking for a project to try my new laser etcher, so here is the result: A LED illuminated sign in acrylic. Most of the material I had laying around except for the bright LED, battery holder and battery. In this instructable I'll give you the outline of how to do it so you can create your own. The steps are broken follows:
1) Manipulate the image for etching.
2) Test etch and cutting of design.
3) Final cutting. (Had to repeat as the acrylic had a scratch on it I hadn't seen earlier!)
4) Cut grove in wood plinth to hold the acrylic.
5) Drill hole for LED.
6) Drill holes for battery holder and switch.
7) Sand paint plinth.
8) Glue acrylic.
9) Wire up switch, battery and LED. ( See the summary for different assembly technique)
10) Insert battery and switch on and be amazed it worked!
Step 1: Materials and Tools
As I said in the intro I had a lot of the material laying around (who doesn't have scrap acrylic pieces, wood and switches laying around??)
1) Clear acrylic big enough to hold the logo. Mine was about 4 x 6 inches
2) Scrap wood about 3 x 5 x 1 inches for base or plinth
3) Small switch - I had found a small toggle switch on my parts bin.
4) Bright LED in the color of your choice. My sons's was green - I didn't have a green LED so had to buy one!
5) Battery holder for coin size batter - CR 2032
6) Battery CR2032
7) Paint, sandpaper for finishing wood base.
8) Glue (I used E6000)
1) Various hand tools like a saw, file, ruler, straight edge, clamps.
2) A Forstner bit.
3) Soldering iron
4) Laser etcher
5) Drill press ( or just a drill and a steady hand.)
Step 2: Manipulating the Image
For the Laser etcher to etch and cut you need to convert the image. For example, the black area of the logo I turned blue. This tells the laser to etch this part. I designed the cut out ( tombstone shape) and saved that as red. This tells the laser etcher to cut this part out. I designed the cut out over the image file so I could get size and registration correct. I then saved the file as two different files. One for the cut out and the other for the etch part. I used Inkscape to do this. Designing the tombstone took the longest part as I'm not proficient in Inkscape, but did manage it. There are plenty of tutorials Inscape and using for laser etching I have discovered, so I need to study more.
Once you are happy with the design I suggest testing it out on a scrap cardboard first. Once you are sure the logo etches and the cut out goes cleanly around the design, then it's time to try the acrylic. When etching plastics alway make sure you are in a well ventilated room and the laser etcher extraction fans are working. Wearing a mask is also helpful as it smells horrible and it's bad for you!
Step 3: Wooden Plinth
I had some wood lying around so I used that. It was about 5x3x1. I marked the center and drilled a hole for the LED. I then marked the top of the plinth where the acrylic was going to centering it. I then used a router and a small 1/8" bit to cut a small groove.
I then drilled a hole in one side where the switch was going to go. I did this before using the Forstner bit to drill out the component holes. I drilled three holes each about 3/4 inches deep into the wood making sure not to go all the way through. The holes are overlapped so the wiring can a easy fit in.
I then used some black spray paint to finish of the plinth. I used two coats and sanded in between to get a nicer finish. For your version you use varnish, different color it's your design.
Step 4: Assembly
To make sure the sign is at 90 depress I used a small engineer's square tool I had in my tool boxed simply secured with a rubber band. I used E6000 glue in the small area I had routed and just pushed the acrylic in. I let it set for 24 hours to be on the safe side.
I then glued in the LED, making sure it was snug against the bottom of the acrylic, using the same glue and let it sit for 24 hours. I'm usually impatient and try to do the next step while the glue is not fully cured and this usually ends up in having to re-glue or start again!
Step 5: Wiring
It's a very simple circuit - batter holder to switch; switch to LED; LED to batter holder. However, you have to get the polarity correct. Usually the longer leg on the LED is the positive side. So in summary:
Postive side of battery holder to switch;
Switch to positive leg of LED;
Other leg of LED to negative terminal on the batter holder.
I tested the connections before soldering it all together. Once you have the connections correct you can solder the wires. I used heat shrink tubing on the LED legs to avoid any shorting out when putting everything place. I also glued the battery holder in place, making sure it was below the bottom of the plinth. That way there is no unevenness when it's standing up. The little toggle switch I used has a screw thread and lock washer to hold it in place. If you were careful with the drilling of the switch hole and the Forstner hole, you should have enough wood left in place to hold the switch. This was the reason for drilling the switch hole first. As I eyeballed all the hole drilling except for the LED I didn't supply any measurements for the holes.
Step 6: Summary
Well it worked as I wanted and my son likes it, the real goal!
Things to improve on:
1) Spend more time on image work for the cut out and etching pieces.
2) Practice more on cardboard before committing to the acrylic. I did go a through a few pieces, but it was all scrap anyway. But if I had bought it specifically I would have ruined a couple of pieces costing money.
3) Make the LED hole smaller. You can see I have too much light coming out the front instead of inside the etching. I also read on a similar design to flatten the lens on the LED slightly and make a small indent on the acrylic for the light to fuses into the material better. So if I do an other version I will try that.
Alternate method for logo etching.
If you don't have access to a laser etcher you can use a Dremel type tool and hand etch the design. Print it out and stick it to the acrylic and then carve the design through the paper. Need a steady hand.