Yet Another Edge-Lit LED Sign

There are kind of a lot of them. But then, everybody does like glowing things, yes? Yes, of course they do. Things that glow are awesome.

I needed a project.

I felt that the Bergen hackerspace needed a cool sign.

Karlmag shared that opinion.

Thus it was only logical that we team up to build one.

Skill: Moderate

Time: Lots

Kilos of mixed nuts consumed during project: 4.2

(Requires basic knowledge of: hand tools, woodworking, metalworking, electrical wiring and soldering.)

Hahaha, wow, this Instructable turned out huuuge, didn't it? Ah well, better too many photos and information than not enough.

Epilog Contest

Yes of course Chimera and Karlmag want a chance at acquiring a laser cutter. (Who wouldn't want a laser cutter? Boring people, that's who.) In the event we did win it, it'd go to the Bergen hackerspace, which is in the process of doing a bit of renovating and trying to expand its tech base, and having a laser cutter would be amazing.

Hand Tools Only (and any other) Contest(s)

Same deal applies: pretty much anything we might win would end up at Hack Bergen for the use of all members.

Tools & Materials

• Computer
• Printer
• Fine-tip marker
• Steel ruler
• Clamps
• Squishy plastic sheeting used as a non-slip mat
• Dremel 300-series rotary tool
• One conical cutting burr and several sizes of spherical cutting burrs
• Dremel 335-01 plunge router attachment
• Dremel 225-01 flex shaft attachment
• Palm sanders
• Car buffer
• Safety glasses
• Ear protection
• Anti-vibration gloves
• Respirator
• Slab of clear acrylic
• Smaller acrylic scrap for testing purposes
• Paper
• Not-exactly-contact-cement glue
• Sandpaper
• Autosol polishing paste
• Vacuum cleaner

Have access to a laser cutter or a CNC machine? Lucky you; go use them. This part will go much faster. The Bergen hackerspace doesn't have either of those bit of equipment, so this is all hand-engraved. It took a few hours.

Okay, it took a lot of hours.

(Want a burr case like the one pictured in the third photo? There is an Instructable for it here.)

Draw or otherwise acquire whatever image it is you want on the sign. For our project it's the Hack Bergen logo. Things show up best when they're engraved from the reverse, so remember to flip the design. Open it in your program of choice and scale it to the size you need.

Before you hit Print, double-check that you have indeed flipped the design. Then check it again. Then print it.

If the image had to be split across two or more sheets of paper to get it the size you need, line them up and tape them together. This one was printed across two pages of A4. Position it on the acrylic and mark around the corners so things can be easily lined up again.

Usually I stick the pattern to the layer of protective plastic sheeting and do my best not to rip it off while I engrave it so everything comes away clean at the end. If there is no protective layer and the piece of acrylic is small enough, I cover it in clear packing tape to prevent scratches. Ours measured 50cm x 40cm (by 8mm thick), which was a bit on the large side to do the tape thing, and had been kicking around the hackerspace for months, or maybe years, and whatever protective sheeting used to be on it was long gone, so we glued the printed design right to the plastic since we were going to have to buff out the accumulated damage afterwards anyway.

Apply the contact cement to the paper. Get a layer of glue on as much of the surface as you can so the paper doesn't start peeling off completely the moment a burr cuts into it. Smear a thin layer of contact cement on the acrylic too, keeping it inside the guide marks made earlier. Use said marks to get everything properly lined up and press the paper into position.

Once the paper is stuck good and secure to the acrylic, clamp it to your workbench in preparation for engraving.

Get your protective gear on. Definitely safety glasses, hearing protection strongly encouraged, anti-vibration gloves are not 100% necessary but still very nice to have, aprons are entirely optional but do make it easier to brush away the plastic shavings, and closed-toe shoes are just a good idea in general in any workshop.

Use a scrap piece of acrylic to do a few test cuts to get a feel for things and test out different burrs to find the one that handles best for you. We went with a conical burr for the first cuts, though if Chimera does this again she's just going to jump straight to a round one.

Set the cut depth. Get the Dremel in position with the first line you're going to cut and lock the guide fence distance. Eyeball it again to be sure it's in the correct place, then turn it on and start engraving. Depending on acrylic thickness, several passes might be needed to get it cut to the right depth. Go easy and don't force the burr along, especially if it seem to catch on something. Shoving it through is a good way to slip and mess up the cut (and possibly yourself), so back it up or back it off to a shallower cut depth and try again gently.

The glue-covered paper does tend to gum up the burrs something fierce, so we had to stop now and then to de-gunk them.

Once all the individual cuts along one level are done, line up with the next one and readjust the guide fence. The guide rods were just long enough that we could just reach every part.

The guide fence only worked for the horizontal and the vertical. All the diagonal and curved lines had to be done freehand. Same general rules apply: test out things on some scrap first to get a feel for the motion of the burr (it will tend to pull more one way than the other), go gently, don't force things.

We probably could have done all the horizontal and vertical lines to their final depth using the plunge router, but it was taking forever so Chimera did the rest of it freehand to speed things up.

It's a lot easier, for Chim anyway, to see where to engrave if the paper pattern printout is removed once everything is outlined with the shallow cuts, though of course this is optional. (If your acrylic still has the protective layer on it, for instance, maybe leave that on to make your life easier later.) Peel/scrape it off. Doesn't matter if there is a bit of scratching on the acrylic because it'll get sanded and buffed all smooth later anyway.

Once again, same general advice applies: several shallow passes are better than trying to cut it to final depth all in one go. Your hands are a lot closer to what is essentially a ball of tiny razor blades whirling at several thousand RPMs.

Chimera is stupid proud of her engraving job on this, by the way.

Time to get the last of the glue residue off of the acrylic and sand/buff out the scratches and dings. The smaller palm sander only took those weird Velcro-y sheets made specifically for it, and those only went to 240 grit, so we used another palm sander the finer grits, all the way to ~2500 grit sandpaper.

After sanding came buffing, to make everything smooth and clear so the light only refracts on the engraved areas.

Engraving done!

Put the acrylic sheet somewhere safe, especially if it's like ours and no longer has any protective covering on it. We put ours in the window with LEDs underneath it. Maybe not the safest place, but we were too impatient for the whole sign to be done before we showed it off.

Tools & Materials

• various rulers
• adjustable protractor/angle-guide thing
• mechanical pencils in 0.7mm and 0.3mm
• eraser
• more eraser
• calipers
• a very tattered RGB LED strip.
• A3 graph paper with 1cm x 1cm squares subdivided every millimetre

For practical reasons, and since we could, the drawings were done to actual size.

At first, Chimera tried planning and rendering the frame in 123D Design. Autodesk's 123D Design software does not, in fact, behave anything at all like Autodesk's Inventor software, with which Chimera is far more familiar. There resulted much frustration, followed by much cursing. Karlmag found it all highly amusing.

It's a good sign you've maybe been doing too much work on the computer lately when you're seized by a sudden panic of: "Oh crap, I haven't saved my work in like three hours now!", sense the muscles in your hand reflexively go for that CTRL+S motion, fail to feel a keyboard, then look down and go: "Oh yeah. Paper. Right."

A rectangular base would have been so much easier to do, but those are boring. Trapezoids look much cooler.

Tools & Materials

• Not-actually-blue blueprints made in previous step
• Steel rulers
• Square
• Tape measure
• Mechanical pencils
• Hand saw
• Mitre saw
• Coping saw
• C-clamps
• F-clamps
• Pipe strapping (metal strip with a bunch of holes in it)
• Power drill
• Drill bits, 1mm up to 10mm
• Ratcheting screwdriver/socket wrench
• Adjustable wrench
• Assorted pliers
• Assorted screwdrivers
• Hammer
• Dremel rotary tool, 300-series
• Dremel 225-1 flex shaft attachment
• Cutting disc
• Cylindrical cutting burr
• Tiny bench vise
• Pin vise
• Block planes
• Palm sander
• Sandpaper
• Reclaimed wood and plywood and particle board
• Wood pegs, 10mm diameter
• Angle brackets
• Wood screws in various lengths and diameters
• Bolts
• Nuts
• Acorn nuts (not that sort of acorn nor that sort of nut)
• Washers
• Painter's tape
• Duct tape
• Ancient touchscreen stylus
• Super glue
• Wood glue
• Wood filler
• Large plastic sheet
• Some rocks
• Grey primer
• Black spray paint
• Matte varnish
• Scrap fabric
• Rubber anti-slip feet
• Vacuum cleaner
• Possibly some more things I don't remember right now

All the wood we used was reclaimed. Zerblatt, another Hack Bergen member, was doing some home renovations and let us dig through the junk pile for anything we could use. The sign's frame is made from old baseboard and door frame mouldings, while the base is made from some old plywood scraps. The base's front and back panels are made from an old particle board sliding door we fished out of a dumpster in front of one of the industrial buildings along the road to the hackerspace, which was also renovating at the time.

Have (access to) a table saw? Lucky you. Use it. Use it use it use it. We didn't have one, so this was all done with hand tools and took us dozens of hours over several months, instead of a few hours over several afternoons.

Because this stuff used to be old baseboard, it's full of nail holes. We cut around the worst, but couldn't avoid them all. The tube of wood filler in the 'space was all dried out and useless, and we didn't want to wait until we could get to the store to buy new stuff. Super glue + wood dust makes a pretty good substitute if you know how to use it, plus it dries quick.

It is old reclaimed wood, so it's time to make it pretty and also just a little bit less warped, because oh boy were some of these pieces ever warped.

The frame's top bar is the easiest to assemble. Allow the glue to dry overnight for best results.

One side of the frame is assembled just like the top, except it's the outer layers that protrude farther than the inner layer this time. Apply glue, align the outer edges, stick the pieces together, clamp it and set it aside to dry.

The other side also has the outer layers protruding farther, but the inner layers are a bit more complicated because this is the side with the channel for the LED strip's power cable.

It took a lot of thinking before deciding just how we were going to bolt this whole mess together. We wanted to be able to disassemble the entire sign in the event of LED strips or other part of it ever needed to be repaired or replaced, but we didn't want huge steel bolts sticking off the sides either (and the frame isn't thick enough to recess them without compromising structural integrity anyway). We settled on wood pegs: sturdy enough to hold things together, can be sanded flush with the rest of the frame, can be knocked back out if the need arises.

This part of the design may have been slightly more complicated than necessary. The bottom edge of the frame melds into the base, and is comprised of two thick pieces of wood buttressing two narrow-but-taller lengths that form the frame itself.

Tools & Materials

• Strawberries
• Paper towel

Also recommended

• various other types of snack food
• assorted beverages

Not recommended

• the adult kind of beverage unless the project is done or you are calling it quits for the day, because alcohol combined with power tools or really any tools at all is A Bad Idea

It is difficult to overstate how important this step is!

It may be the most important step of the whole process!

Alternative approaches:

• having a Snack Break between all the regular steps
• having a Snack Break sub-step on each step
• all of the above

It is important to note that the last entry also opens up for the possibility of having several Snack Break steps in each regular step. Even more important; you can have recursive Snack Break steps!!!

The frame sides go clear to the bottom for structural reasons, but they have to go through the base top to get there. That means cutting some holes for them.

A slight design over-complication we had to incorporate because the base's top and bottom are the longest we could possibly get out of the slab of plywood we used, yet still too short to extend far enough that the frame sides don't bump up against the end plates when everything is assembled.

Rectangular prisms may be easier, but where's the fun in "simple"?

These are the last pieces to attach and then the base is done.

Trimming the pieces that were just added so they merge smoothly with the other angled parts.

The power cable for the top strip needs to be able to get into the cable channel inside the frame. Time to drill a hole for it.

Friction with the base isn't enough to hold the frame in, at least not if you want something properly secure, so it's time to add some hardware. Drill the holes for the LED control box's infrared sensor and the power cable while you're at it. (And pretend like we haven't actually painted the thing yet. We were making everything up as we went and did the steps in not quite the optimal order.)

"Oh yeah, we still have to do this other thing that we forgot about and that will completely trash the paint job. Whoops." Keep pretending it hasn't been painted yet. Or pretend like we did it on purpose to increase the photographic contrast.

Now we could have just left the frame edges all right-angled and blocky-looking and ew, but that would not be in keeping with the overall form we have going on with this thing.

We had several discussions on what to use for the front and back panels, and then found something perfect in a dumpster down the street from the hackerspace.

More stuff that would have been so much easier and faster with a table saw, but you work with what you have. Even if we had managed to acquire a table saw in the interim, I think we would have finished it completely by hand just on principle.

The panels are made of particle board, which means the edges will be all chipped and generally ugly and not smooth. Make smooth with wood filler.

Locate and fill any dents, chips or cracks that might remain, let dry, sand smooth.

Tools & Materials

• Scrap brass plates
• Cardboard
• Pencil
• Dental pick
• Graving pen
• Scrap wood
• Clamps
• Coping saw
• Metal files
• Sandpaper
• Power drill
• Assorted drill bits
• Dremel 300-series rotary tool
• Bench vise
• Brass hinge screws
• Screw tap and die, M2.5 x 0.45
• Black porcelain paint (Marabu Porcelain)
• Household oven

For the Etching

• Pieces to be etched
• Duct tape or other tape
• Spray paint
• Hydrogen peroxide
• Hydrochloric acid
• Small non-metallic container used as a measuring cup
• Glass jar for mixed etchant
• Funnel to pour the used etchant into a bottle for storage and eventual re-use
• Paint thinner to remove the spray paint after etching is done
• Splash goggles
• Respirator
• Nitrile gloves

It was decided we wanted a little bit more secure anchor point for the power cable than just jamming the socket in a hole in the wood, so Chimera made some decorative brass plates, because black + gold = classy. Of course they are in keeping with the whole trapezoid thing this whole frame has going on.

The metal etching was done with the 2:1 hydrogen peroxide to hydrochloric acid method detailed in this Instructable.

Painting the wood pegs fastening the corners wasn't the ideal solution to hide them, thus decorative plates over them too. The front and back panels could probably have been left as they were, but since they're made of particle board -- not known for spectacular structural strength; the brass plates will spread any force over a larger area -- and the black colour of the acorn nuts just looked blah against more black, the front and back panels got some fancified hardware too.

Chimera was real tired of cutting and filing brass by the time this project was finished.

We couldn't find any screws in brass, or at least brass-coloured, that were small enough for the plates in any of the hardware and hobby stores around town, so Chimera dug through her parts bins at work and turned up some old, tiny brass hinge screws. The heads were huge, but that was a problem that could be easily solved with a Dremel and some files.

The other problem with the screws was the thread count. M2 x 0.45. The smallest nuts to be found anywhere local were M3, and we didn’t want to wait for the time it would take things ordered from abroad to arrive, so we made our own nuts. They may not be pretty, or even particularly nut-shaped, but they do the job just fine.

"Measure twice, cut once," is a maxim for a reason. Careful measurements are needed here.

Tape off all the places you don't want or need paint to be. Work in a well-ventilated area, wear a respirator, follow the usage directions on the can.

The acrylic is 8mm wide, while the baseboard and moulding is 10mm wide. This was okay because it let us add a layer of fabric along the edges, which would help hold the acrylic, let it slide in more smoothly during assembly, and prevent light bleed from the LEDs. The fabric was some scrap from a coat I was working on.

Tools & Materials

• Soldering iron
• Lead-free solder
• A piece of prototyping board, strip board type.
• Connectors
  • 4 pin single row breakaway pin header, round type
  • 4 pin right angle
  • 4 pin straight

• Eye protection
• Some means of getting the soldering fumes away from your face. (Fume extractor, fan, open window, fellow hacker waving a sheet of cardboard, etc)

The strip board and the connectors are all 2.54mm (0.1") spacing types.

The round pin headers were put in to be able to connect the RGB control box directly to the board.

The other connectors where chosen because we already had them available and because they are unidirectional, so you cannot (easily) connect them the wrong way around. They are actually the same type of connector that was being used as power connector on 3.5" floppy drives, for those remembering those. ;-)

You can obviously use connectors with different spacings or different types depending on what you like and have available.

The straight and right angle connectors are sold as "Series 2500 wafer connectors" by Tayda Electronics.

Direct links: 4 pin straight and 4 pin right angle

They are really standard connectors and should be easy to source everywhere. They will probably go by many different names though.

Would it have been simpler to have one continuous LED strip with one connection? Probably, but we put a separate LED strip on each side with the goal of eventually connecting them to some microcontrollers so each strip could be programmed individually. For now they all plug into the one control box that came with the roll of LED strip.

Internal power cable, that is. One end is the power socket that mounts in the side of the base, and the other plugs into the control box.

If your acrylic still has a layer of protective plastic on it, now is the time to remove it.

Gaze lovingly upon your marvellous creation that took way to freaking long to build but is totally worth the time and effort.