LED "Solar Lights"

Okay, so you really want to know what the hell is inside those solar lights they sell at Walmart and Home Depot, huh?  Well, here is the schematic of one such unit:

The light in question is a "Malibu" model LZ3W marketed by Intertec.  I bought the one I reverse-engineered at Walmart for $11.43, plus tax (not on sale).  I just had to see what made these lights tick.

I knew there had to be a voltage boost circuit.  They are powered by a 1.25V NiCd battery which, by itself, is not sufficient to light a white LED.  The fact that a solar panel was used to charge the battery during daylight hours was a yawn.  Still, I had to know what was inside.

In the store I opened a box to look at what one receives.  The main guts were packaged in a bubble-wrap baggie.  It was clear that a white LED was there.  Also present was an inductor of some sort, an electrolytic capacitor, and a couple of small, black-body diodes.  That was not enough guts to make this work so I decided there must be additioal guts somewhere else.

After making my purchase and returning home I proceeded to install a standard 1.5V AA battery to see it light up.  It did.  The light was not blinding by any means, but it was probably adequate for the task.  After fondling the main assembly for a few minutes I got out my screwdriver and took it apart.

It became obvious rather quickly, there were a few surface mount components on the "solder side" of the PC board.  I was relieved to see there was no mystery chip as can sometimes appear.  All the components looked accessible and I proceeded to create a schematic for the unit.

Above, is the schematic of the light.  There are additional notes and a fair amount of detail on a PDF document I created.  You probably want that.  Click the PDF symbol and snag it:

  Schematic of LZ3W solar light

Have a look-see and enjoy.  The circuit would make a nice AA-based LED light for power outages.  Maybe I could replace the guts of one of those stupid circular push lights with this.  The battery would last a lot longer than powering an incandescent lamp as is now done.  Better to eat one battery than four!  If one built an emergency light that used a "C" or "D" battery, it would last just about forever.

I had looked for web-based information and came up essentially empty.  So I decided that I may as well contribute what I could.  For about twelve dollars and some time, I got the information I wanted.  The only thing I lack, is a proper inductor for this application.  I bet I can come up with something but have yet to look.  I will consider the DC resistance of the inductor and the current capacity.  Sure, I could probably buy these lights cheaper than I could build one.  But what is the fun of that?  Maybe I'll build a bunch of these and scatter them in the house.  When Commonwealth Edison (my electric company) next fails to provide power, I'll be better equipped than with the tea candles I usually employ.  There are better LEDs to be had, as well.  I can get 18 candela white LEDs for just over a dollar.  I bet the LEDs used in this light are about 5 or 6 candelas.  I can do much better on my own (I think).

VLF Receiver...

Here is the schematic of a Very Low Frequency receiver that might be suitable for capturing "strange" atmospheric noises.  There are "whistlers" and other such noises to listen to if you have a lot of time on your hands.  I am uncertain just how useful they would be in a synthesis environment but here it is in any case.  Just click on the PDF icon below and a schematic of the VLF receiver will pop up for you.  Of course you could right-click on the icon and download the schematic to your favorite download location.  I built one of these on a breadboard.  Initially I was bored stiff and thought "what is the point".  then a few birdies popped into my headphone.  Then I thought, "Gee, that was kinda cool".  After listening for almost an hour I concluded that neat stuff could be heard but patience was definitely required.  It is extremely inexpensive to build, is not critical as far as layout is concerned, and is certainly different that what you've heard before.  try it... you might like it!

        VLF Receiver Schematic