I'm building a basic thermometer that displays the temperature on 4 seven segment LEDs. I want to put the circuit in a box with a clear plastic lid.
I'll mount the LEDs on the PCB around the other components, and fix this flat against the base of the box so the LEDs shine up through the clear plastic lid.
My question is how can I hide the electronics (i.e. the MCU, temp sensor, resistors, etc) but still be able to see the LED display, by some how darkening the clear plastic lid, and make it look more professional?
Alternatively, can you get enclosures with a translucent lid? I've searched but can't find any.
I'll try with a small square of those mirror films used to filter out sun rays from offices with lot of windows, or the black films used to darken car glasses.
There are these mirror foils for smartphones: http://www.amazon.com/gp/search/ref=sr_nr_seeall_6?rh=k%3Amirror+foil%2Ci%3Amobile&keywords=mirror+foil&ie=UTF8&qid=1294916698
These could work!
This website has some tinted plastic normally used for windows and is pretty cheap.
You could mask off the section of the box above the 7-segment displays and then spray-paint the inside of the box to whatever color you like. If the alignment is correct, you'll just see the display.
Alternately (or additionally), take a piece of black paper or card stock and carefully cut out holes for the individual displays. Slide the paper over the PCB, and you'll be covering up your electronics. You could even add labels (or a logo) to the paper, if necessary.
Could you attach a translucent sheet, like the thin Styrene sheet in the Sparkfun clock? "12ft GPS Wall Clock" tutorial http://www.sparkfun.com/tutorials/47 . Perhaps a few layers of HDPE milk jug would be adequately translucent?
Or even simpler: Could you use sandpaper to convert the clear plastic lid to a translucent plastic lid?
Automotive shops sell a spray tint for plastic.. 1 layer gives you a slight tint, the more layers you use the darker the tint..