Ultraviolet Business Card Flashlight

Step 4 The foam insert

Cut out a foam rectangle a few mm shorter on each side than the credit card, and cut a 20mm diameter hole into the middle of one end as shown - exactly where isn't crucial, but it should be close to one end.  A scalpel will help with this.  I cheated and did my prototypes like this, but ran off the rest on my laser cutter.  You can also cut out a notch as shown about the same width as the LED, but this isn't crucial.  To make it easier if cutting out with a scalpel, it actually works just as well if you make the 20mm cutout a square (with sides 20mm) rather than a circle.  Have also attached a PDF of the pattern I used if that helps anyone.

Now you'll need to stick the foam onto the card - I used two strips of special high-strength double-sided tape, but for most people a glue gun will be a better choice.  It works best just putting adhesive along the two long edges I've found.  If you've designed your card with a picture of a button on it like mine, you'll want to make sure the cutout hole is behind the printed button!