I needed some good lighting to illuminate the print bed of my DIY RepRap. I tried to keep it as simple as possible, but still flexible enough to direct the light beam into whatever direction I needed to look at in detail...

So out came this little tiltable and rotatable snap-in frame, on which I mount the easily available and inexpensive round G4 type 12V SMD LED lamps. These are basically small circular PCBs with 5050 type SMD leds and are sold in 6-led, 9-led and 12-led versions. On eBay you can find them for around 1$ each.

The frame consists of two printed parts: the LED holder and the base. These two parts are joined by a conical hinge, so that the angle of the lamp can be adjusted as needed. The conical hinge holds by friction, but screw holes are also provided in case a firmer grip is needed. The led holder is designed to allow as much air circulation as possible around the led carrier, to allow for proper cooling. The frame has a central screw hole so that it can be attached to any flat surface. If a washer is used and the screw is not tightened too strongly, the lamp can also be rotated around the screw, providing full angular coverage. A hole in one corner of the frame can be used for feeding the cables through.

The led carrier is simply pushed into the led holder - it should snap in with a click. Depending on the type of led carrier you get, you might have to unsolder the lateral G4 mount and solder the wires directly to the solder pads located in the center. Note that these led carriers usually also contain a rectifier, so that you don't have to worry about polarity.

The SCAD file that is provided is parametrized, so that the design can easily be modified to individual needs, or also to fit the even larger 15 or 24-led carriers. The provided "ready-to-use" STL files are for the 6-led, 9-led and 12-led versions. (Note that I have no 9-led carrier, so I could not test the 9-led version in practice yet.)

Even though I first just thought of using these lamps inside my RepRap, they have turned out to be useful in many other places as well...

Update 2014-02-03: I just have received a new batch of 6-led modules and, to my dismay, these only have a diameter of 22mm, so the don't sit firmly in the 23mm frame. Thus, I have now uploaded and additional STL file for the 22mm version.