CAUTION: This site describes open source hardware and has open source software. Please read my disclaimer.
Look here for hints and ideas for electronic and other hobbyists, as well as some lighting related info that you might find useful or at least interesting.
You may want to come back here every few months. This site is always under construction!
The most efficient LEDs and where to get them!
I have an LED Main Page. (updated 10/18/2017, some external links noted as updated 5/25/2018.)
Don's Lighting Info Center, go here to see lots of
information about many forms of lighting.
Here you can find basic and advanced theory, other stuff including troubleshooting and repair hints. Lots of info on incandescent, halogen, fluorescent, compact fluorescent, HID lamps such as mercury, metal halide, high pressure sodium, and short arc lamps!
Also info on neon, low pressure sodium, oddballs such as green neon lamps.
Even a bit on UV lamps, night lights, lightbulbs lasting a century, electronic ballasts, and carbon arcs. Also better info on lamps for growing plants.
Added 2/15/2010 - s/p ratios of many light sources!
(updated slightly 11/19/2017)
Don's Laser Top Page.
Ways to hack some cheap laser pointers to obtain boosted power (anywhere from 7 to 30-plus mW) that makes them dangerous and illegal to use as toys! Links to where to get dangerous 15 to 190 milliwatt green laser pointers and 1-watt blue ones as visible as 60-800 mW red lasers would be! NEW - orangish-yellow laser pointers, blue ones, violet ones! Also stuff on He-Ne lasers and more. This includes how to make a UV laser whose lasing medium is air at low-altitude atmospheric pressure, which Ben Franklin could have built - but pre-1960 manmade lasers have yet to be recorded.
(most recent update unrelated to Sam's laser FAQ 5/23/2014, links to V. 14.50 of Sam's Laser FAQ 3/5/2014 and Craig Johnson's laser stuff 4/16/2014)
For links to unmodified official versions of Sam Goldwasser's Laser FAQ, most of them leading to V. 14.5 (current as of 7/21/2015) and none older than V. 9.10 (current as of 3/23/2009), as well as the V.9.10 .zip version, go to my above Laser Page.
(35-plus meg of good stuff, plus over 350 GIFs and JPEGs as of V. 13 - 14.5!)
Don's Tesla Coil page! (No news since 9/22/2008 as of
Includes some nice stuff on Tesla coils in general and on solid state Tesla coils. Submitted to the Tesla Coil Web Ring 10/17/99 (though I have since incurred a failure to be in that webring. New page added 8/27/2001 and this section had a major update on 9/22/2008 (first in 2 years)! Progress continued slowly on one of a few previously noted largish solid state Tesla coils until being backburnered in late 2008. Links added to other sites with working coils and working schematics 7/5/2005.
Don's Xenon Flash and Strobe Page!
Lots of schematics, helpful hints, precautions, xenon flash basics, parts sources, mad ideas, etc. Large strobe stuff, inverter schematics, a blacklight strobe idea (tested), xenon arc lamp stuff, more! Many files linked from here!
(Updated slightly 7/30/2017, not much since 2000.)
My Infrared Page has info on IR sources, IR filters, and IR cameras including webcam and other camera hacking! (updated 3/6/2013.)
Check out my High Voltage Generator Page for a few
circuits to get thousands of volts from low voltage DC.
(Latest update a minor one 3/22/2011.)
Even more things now, like Jacobs ladders, plasma spheres, neon lamp oscillators, etc. To find out how these work and how to make these, go here! (Latest update a minor one 9/23/2008)
Spectra online! Visible line spectra of various elements and a few common light sources. (15 spectra plus a wavelength scale as of 7/4/99, link added to another site 7/4/2005.)
Now lighting and color as far as stars are concerned is here. Although for
now concentrating on Gliese 581, and specifically
theoretically on that red dwarf's discovered-in-2007 "earthlike" planet.
NEW! Hints to make your PC run faster.
Includes Dan Barclay's patch to blazingly improve math coprocessor usage
by Quick Basic 4.5 and other Microsoft programming languages. Also how
to get higher math speed by compromising the math coprocessor precision in
some C compilers! Also simple stuff like more memory, registry cleaning,
and some fairly-easy-and-safe manual registry editing and tweeks!
(updated 2/21/2017, most pre-2005 stuff is moved to a linked page.)
Download Dan Barclay's math coprocessor patch from
here to greatly speed math coprocessor usage by some Microsoft programming
languages, especially Basics (such as Quick Basic 4.5 and Basic 7 / QBX and
possibly some versions of Visual Basic and maybe some C and C++ products) and
executables produced by these programming languages. This is a zip file with
the patch, and lots of usage instructions and hints by the patch author and
also by me. Math speed is usually doubled to tripled, sometimes more.
This may apply mostly only to some pre-2000 Microsoft programming languages or "programming environments".
There is loudspeaker stuff here. Already here:
Plans to get big sound from a cheap 5-inch fullrange, and amazing lower
bass from a Radio Shack 10 inch woofer at home or in a car with a trunk.
Also: Plans for very cost-effective bass bins, also how to make piezo
tweeters sound more natural. Just added: Mad ideas based on the unimportance
of frequencies below 600-800 Hz to the intelligibility of the human voice. Get
more apparent voice PA power with 70 percent less amplifier power!
(Slight update 6/19/2011 but progress here is low since before 2008)
Fellow Electronics Experimenters and Mad Scientists - MAD SCIENTIST CENTRAL - this page is new 8/20/2001, updated 1/28/2016. Links to fellow mad hobbyists (especially electrical) with homepages. Many web resources good for adventurous tinkerers.
Don's Downloadable Software!
Freeware is here now, and as of 1/2/2011 it's all freeware!
As of now, DOS executables are available for all programs available here and BASIC source code is posted for all freeware available here. Requirements are usually a version of DOS absolutely minimum of no more than 2.3, preferably 3.0 or higher, normally available under Microsoft Windows 3.anything, 95 and 98. Windows XP "Command Prompt" at least generally works with these. Some programs require VGA or compatible display (the usual nowadays since 1994 or so).
Number of programs available as of 1/2/2011: 3 freeware. Two deal with blackbody radiators, especially for lighting. The 3rd is a highly improved loudspeaker enclosure one using Thiel-Small parameters and enclosure parameters to predict on-axis frequency response, after many real-world factors.
Sam Goldwasser's site at repairfaq.org!
The laser, strobe, and fluorescent lamp documents that are mainly of his authorship can be found there as well as here. Also tons of other electronics repair and electronics stuff!
Filip G.'s site, http://www.repairfaq.org/~filipg has lots of stuff including Sam's stuff - but with fancier HTML while maintaining high compatibility with the best and worst of web browsers.
Techlib.com's circuit library, supersedes Wenzel, including some interesting ones for hobbyists. Circuits are in PDF format. Link updated 1/28/2008.
A mad gift that I gave one of my brothers for Christmas 2004... (New file added late 12/26/2004)
Willem-Jan Markerink's extensive and nicely technical photography site! Includes extensive IR photography info.