Eric over at Low Voltage Labs has posted up his design for a simple PCB ideal for putting an LED into a pumpkin. This is very much like our simple LED pumpkin project but in a neat, reusable format. And it makes a mighty cute little jack-o-lantern all on its own.
He has made it available as a kit with PCB, switch, resistor, battery holder and the same candle flicker LEDs which we love so much. Unfortunately, the kit is currently sold out. Hopefully he’ll make more, if not in time for this Halloween, then at least for next year.
Well jeez. If you’re going to go to the trouble of printing a board, you might as well make it a joule thief. Or put a timer on it, for when you put it on your porch and forget to turn it off. Or *something*…
How about using one of the flickering LED’s from the tea lights?
Oops, just read closer. Guess it already does, comment withdrawn.
Thanks Lenore. The pumpkin PCB was actually inspired by your Simple LED pumpkins. I bought some of the flickering LEDs from your store last year for myself and a friend. My friend asked me to make a circuit board with a switch so he didn’t have un-tape the LED every night. :)
We are sold out for this year, but check back next year for more stock and a new version of the PCB.
I have been having fun wiring two LED’s in series to a 9V battery. The runtime from a 9V is huge. Instead of hard to find button batteries how about 9Vs?
CR2032’s aren’t hard to find if you shop at the right places, but point taken.
A 9 V is actually a rather inefficient battery– with a lot of internal structure –for times when you really need 9 V. By comparison, it’s extremely efficient to run from two AA cells, or even two AAA cells, if you want 3 V.
Typical capacity for a CR2032 is ~ 230 mAh @ 3 V. Typical capacity for an alkaline AA is 2700 mAh @ 1.5 V. Typical capacity for an alkaline AAA is 1200 mAh @ 1.5 V. Typical capacity for an alkaline 9V is 565 mAh @ 9V.
Running two LEDs in series @ 20 mA from a 9 V should last about twice as long as from a coin cell. But, running from two AA cells should run more than ten times as long.