Mini Acrylic Edge Light

Make a little edge light for thin acrylic panels. Runs off a 9V battery and glows white. Can be attached to a hanging panel, or stand it on its built-in feet.

This project was created for The Science Factory "Taste of Science" fete. All design work is by MDIM, courtesy of make717. It is based on our flashlight project and designed to light the logo on our Spirograph project.

Step 1: Gather Your Tools and Materials

Gather parts and materials:

• 3-LED/12V strip, like this one salvaged from a 3D printer. Any 8mm wide strip should work.
• Battery Clip, modified from a hard plastic T-clip.
  Copy and paste these keywords into the search box at eBay: 9V 6F22 Black Battery Snap Connector clip Lead Wires Holder T-type HardSwitch.
• Flashlight Switch. Copy and paste these keywords into the search box at eBay: 1A 30V DC 250V black Latching on off mini torch push button switch
• 9V battery
• Tinned bus wire
• PLA filament
• .118" (2mm) Acrylic

Gather tools:

• Soldering iron and solder
• Wire cutters Scissors
• X-Acto knife or similar
• Sharp tool like a heavy needle or an awl
• 3D Printer
• Laser

This project uses many of the same components as our flashlight project, so if you build one, build the other.

Step 2: 3D Print the Edge Light Housing

Print (or have someone print) the attached STL file.

TIPS:

• Print with the switch hole down. In this position, you shouldn't need a raft or supports. A brim is recommended for best adhesion.
• Use PLA.
• On a MakerBot Dual Gen 1, this file takes 4 hours to print. Plenty of time to make your acrylic panel...

Step 3: Create Your Acrylic Panel

Whew! this could be a full instructible by itself. Here are some guidelines:

• The model featured here is for Optix .118" (2mm) acrylic from Lowes. Because you can buy cheap, full color LED edge lights for 1/4" (6.35mm) acylic. And nobody uses 3/16" acrylic, right?
• The clip covers an area of .8" X 2.5" (20mm X 63mm). Don't put engraving in this area - you won't see it.
• Light cutoff is sharp at the edges, because of the rectangular LEDS. You could add a diffuser, I suppose. Let that be a design challenge for the comment trolls.
• The best light effect comes from having the edge of the acrylic touch the LEDs. So a straight edge where you are going to mount the clip is a good idea.
• Don't cut your artwork too deeply; the acrylic will develop stress cracks.

Step 4: Cut the LED Strip

Clip a 3-LED segment from your strip. The segments should be clearly marked where to cut.

Step 5: Punch Solder Pads

Using a sharp tool, punch through the solder pads on the tape. A heavy needle or an awl works well for this.

Don't try to drill the holes - the bit will grab and tear your LED strip.

Step 6: Remove Solder Mask

Because you punched the holes, there will be a nice dimple in the solder pad. Put the tip of a sharp hobby knife in the dimple and spin it until the pad is nice and shiny. Don't go too deep - you'll scrape off the copper and have nothing to solder wire to.

Step 7: Solder Bus Wire

Follow the process in the photos above:

• Cut a length of tinned buss wire and bend it into a U shape.
• Poke each end through the holes in the solder pads.
• Solder in place.
• Trim away the U, so you have two separate leads coming out the bottom of the LED strip.

Step 8: Preform the Leads

Bend the wire on the "-" side ninety degrees, as shown.

Step 9: Preform the Switch Leads

Bend down one lead of the switch, as shown.

Step 10: Prepare the Battery Clip

Our battery clip is modified from a hard plastic T-clip, which comes in bundles of 100:

• Pry the plastic cap from the clip using a small screwdriver.
• Clip the two wires inside close to where they are crimped to the contacts.

TIP: Do this as busy work in front of the TV, and bag the clips for use later. The wires make great jumpers for your Arduino project.

Step 11: Solder the Switch in Place

• Feed the bent lead of the switch into the positive (+) terminal of the clip. That's the bigger terminal.
• Solder in place.

TIP: Limit the solder time to 3 seconds or you may melt the plastic on the battery clip.

PRO TIP: You can build the jig shown in the photo. See our flashlight project for details.

Step 12: Solder the LED "-" Lead

• Feed the bent lead (-) of the LED into the negative (-) terminal of the clip. That's the smaller terminal.
• Solder in place.

TIP: Limit the solder time to 3 seconds or you may melt the plastic on the battery clip.

Step 13: Solder the LED "+" Lead

The "+" lead of the LED strip gets soldered to the switch.

Cut the lead so that the strip lays along the side of battery clip. You might have to bend the "-" lead to get everything in place. Make sure the "+" and "-" leads don't touch.

TIP: Limit the solder time to 3 seconds or you may damage the switch.

Step 14: Add a Battery and Test

Snap the battery clip on top of a 9V battery. If the LEDs light up, you're good. If they don't, try pressing the button a few times - the switches tend to misbehave when soldered. If the LED still won't light, proceed to Troubleshooting, below.

Step 15: Install the LED Strip

Looking inside the plastic housing, you will see a slot for the LED strip. It has two tabs to retain the strip. Insert the LED strip under the tabs and slide it to the end of the slot.

Step 16: Seat the Battery Clip

The battery clip should line up with the plastic collar inside the housing. Press the clip in place - it should snap down over the sleeve. If it doesn't want to snap, check for stray plastic around the pips on the side of the sleeve.

The picture shows the clip in place. You can use the battery (not shown) as a tool to help press the clip over the pips.

Step 17: Install the Acrylic Panel

Your acrylic panel should slide into the slot.

Step 18: Enjoy Your Work

Turn on the switch, turn down the room lighting.

Step 19: Troubleshooting

LED strip doesn’t light?

• Check the LED leads - "+" goes to the switch, "-" goes to the smaller contact.
• Check the switch - is it connected to the "+" contact of the battery clip?
• Check all solder joints.
• Check for crossed leads (short circuits).
• Using a multimeter, check the LED strip for continuity.
• Using a multimeter, check the switch for continuity. If it does not conduct electricity, press the button and test again. Expect a 5% failure rate on these switches, usually from overheating during assembly.
• Using a multimeter, check your battery. It should produce at least 6 volts. The LED strip is rated for 12 volts, so you may get unpredictable results as the battery discharges.