Caving

To contact Ray you can e-mail him at:

For more information about caving in the United States you should visit the National Speleological Society web site.

This year the annual convention is in Marquette Michigan. See you there!

This is the ABSTRACT for the LED caving light that was presenting at the Communications and Electronics Session at the 2001 NSS Convention.:

This design uses four parallel strings of six Nichia White LEDs in series. You don't need as many LEDs to match the strings as you do when they are all wired in parallel. The circuitry is based on the MAXIM 1698 integrated circuit that has provisions for efficient dimming and switch mode operation using an external MOSFET. By carefully selecting the inductor and other components for low loss, it’s possible to achieve efficiencies greater than 90% using surface mount components. The electronics and 24 LEDs are mounted on a 1 ¼ x 1 ¾ inch printed circuit board.

The photo above shows one of the 24 LED lights using an external inductor to achieve over 90% efficiency. A smaller inductor can be mounted directly to the PC board but only achieves 80% efficiency. The potentiometer is used to vary the intensity.

The close up of the PC board below shows the MAXIM 1698 integrated circuit is located in the lower left corner of the PC board. The four resistors that are in series with each string of LEDs are in the lower right.  The tiny MAXIM IC requires the use of a PC board and some skill with surface mount components.  This is the first generation PC board.  It's often best to mount the components on one side and the LEDs on the other.

The figure below shows the completed LED assembly mounted in an Easter Seals headlamp.
The PC board fits nicely in one of these inexpensive headlamps.