DHS tribute threat level indicator

I believe there are three DIY remakes of that design in existence today:

Doug Jackson's version: uses etched copper board. I do not like the aesthetics of this one, although your mileage may vary.

Christian Aschoff's take: letters cut out in vinyl by a commercial printer, then applied to the back of an Ikea picture frame. The result is very nice.

Ruud Burger's approach: a nearly perfect, verbatim copy using a large-format vinyl cutter, paper backing, and a wooden frame. Looks great in low light.

Yup, that's right.

1. Preparing the display surface

After removing the protective foil and masking it properly, I applied several coats of generic, glossy spray paint to the back of the sheet. My hope was this will yield a nice, shiny surface when viewed from the other, non-painted side.

Surprisingly, this assumption proved to be correct:

Note that once the foil is peeled off the front, you need to handle it with care - it scratches easily.

2. Adding illuminated text

With the toolpaths done, it's time for CNC machining! I mounted the sheet, painted side up, on my Roland MDX-540 mill - and sent the data to the device.

Here is the result of this work - so far, so good!

3. Finishing touches

I also poured some translucent, tinted epoxy resin into the machined letters; this makes them nearly invisible when backlight is off, and diffuses the light when the illumination is on. I used MAX CLR HP epoxy from Polymer Composites, mixed in some alumina to make it translucent, and then added 7701 series transparent dyes from Eager Plastics.

The result, when held in front of a light source, looks this way (protective film still installed, hence the halos):

4. Electronics and final appearance

Various views of the completed project:

A crummy video of the device in action can be seen here (white balance isn't great):

Oh, and my son's version is here.

5. Closing words

What's the total cost? The materials and electronic components cost under $15. The project should take no more than three days to build.

The materials and electronic components cost under $15. The project should take no more than three days to build. Will you make me one? Nope, sorry. I can send you CAD models, NC toolpaths, and a detailed parts list, though. If you don't have a mill - in many regions, you can get much of the work done at a local makers community center or at a college; or you can send it to a commercial company to do the machining for you.

Nope, sorry. I can send you CAD models, NC toolpaths, and a detailed parts list, though. If you don't have a mill - in many regions, you can get much of the work done at a local makers community center or at a college; or you can send it to a commercial company to do the machining for you. Damn, CNC machines are expensive, right? Not really - you can own a seemingly decent CNC mill for $600 or so, and set it up at home. It's actually far more practical than MakerBot and similar prototyping tools - click here to read more.

Not really - you can own a seemingly decent CNC mill for $600 or so, and set it up at home. It's actually far more practical than MakerBot and similar prototyping tools - click here to read more. Can I do it without a CNC mill at all? Yes - using vinyl cutter is another obvious option. Many companies offer inexpensive, custom vinyl cutting; and desktop machines start under $200. See Ruud Burger's or Christian Aschoff's work mentioned earlier on this page.

Yes - using vinyl cutter is another obvious option. Many companies offer inexpensive, custom vinyl cutting; and desktop machines start under $200. See Ruud Burger's or Christian Aschoff's work mentioned earlier on this page. Why not just use black acrylic? You would need to machine letter outlines all the way through the sheet, thus sacrificing the seamless appearance of the front surface.

You would need to machine letter outlines all the way through the sheet, thus sacrificing the seamless appearance of the front surface. Then how about machining in black acrylic, and then placing another transparent sheet in front? That may work, but gluing them together without leaving any marks is not trivial. Spray painting is pretty hassle-free in comparison.

That may work, but gluing them together without leaving any marks is not trivial. Spray painting is pretty hassle-free in comparison. Why DHS threat levels, anyway? In short, I'm a great fan.

If you have any other questions or comments, you can reach me at lcamtuf@coredump.cx. I am also on Twitter.