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PPDC Entomology lab


Dome lighting for insect imaging under a microscope

Build Instructions for Dome Lighting System, using the KD-200 Ring Light

Please note that references to specific products below do not constitute endorsement. Equivalent dome systems may be made with similar types of materials, from a variety of sources.
An effective and easy lighting arrangement setup begins with a pre-fabricated LED ring light such as the KD-200, produced by Gain Express. This particular ring light has 80 warm white LEDs, is powered by 14 volts DC converted from 110-240 volts AC by a universal adapter, and has a control unit with an on-off switch and dimmer. The total cost of this unit, including shipping is approximately $110.
Importantly, the KD-200 has an interior staging space that is 56mm in diameter, which allows a specimen to be positioned at the center of the stage when the pin is held horizontally. The overall diameter of the light is 98mm.
For positioning horizontal pins, a 40mm tall foam post may be attached with double sticky-tape to the wall of the inner rim, as seen to the right. Alternatively, modeling clay (preferably gray in color) may be used to hold the specimen pin in place.

To create a foam pinning surface to the stage bottom, cardboard and gray foam discs, together measuring 70mm in diameter and approximately 10mm thick, are inserted from below. If using clay instead of a foam post, the notch in each of the gray foam bases as seen to the right, is unecessary.

The foam we've employed is gray closed cell foam, EVA grade, 1/4" (6 mm). This isn't perfect, because the insect pins leave holes in the surface. So other foams may be equally or even more suitable for this application. If you have experiences with other types of gray foam that work as well or better, please let us know (Peter/Eric/Matt). We have yet to experiment with crosslinked polyethylene...

These discs are held in place up against the bottom of the 56mm inner rim by the three mounting screws included with the ring light.
The top of a plastic water bottle is ideally suited to serve as a dome for the KD-200 system. Pictured is the "H2O on the GO Jr.," 1L/ 32oz. size, sold at Walmart or Target in the USA for about $1.50. This bottle is about 105mm in diameter.

The entire top (immediately above the inset handle) and the 15mm long spout is cut-off, leaving a hemispherical dome, with a 27mm wide oculus. Four or six small screws (about 2mm diameter, 10mm length) are placed equidistant around the bottom (about 10mm above the edge), so they project at right angles into the dome.

If you are a Nikon Coolpix 990/ 4500 user, use six screws - which makes the dome strong enough to bear the weight of the Coolpix, so the dome can be used as a macro stand for this camera.

The dome is spray painted with at least two coats of white enamel. The first is textured, which leaves a 'pebbly' finish to enhance light dispersion inside the dome slightly and to provide a nice surface for gripping the exterior of the dome. The second coat is flat white.
Additional painting, using flat black, may also be desired for providing directional lighting effects.
When the dome is placed on top of the ring light (with the screws resting on the outer ring light rim), the dome light is around 72mm tall.
Alright, now you should be ready to go! Congratulations!
Have at it!
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