the only other method I’ve used is to tie them all with
another piece of wire. Then, of course, as soon as I do
that, I realize I need to connect another lead or two to
the tied and soldered bunch of leads.
The material I’ve found that works really well is
something we all throw away or recycle. This past week,
I noticed that my wife had recycled a plastic wrap box
It wasn’t very flat, so I removed it to take it apart
and flatten it. I noticed that the metal cutting edge was
still attached to the box so I removed it to place it into a
different recycling bag.
In looking at it, I wondered if I could solder something
to it. So, instead of recycling the cutting strip, I tested it
and found that soldering to it worked very well. I decided
to make a night light out of a joule thief circuit using two
small pieces of this material as soldering islands.
These islands made soldering multiple wires to the
same point very easy, even though they were not attached
to a board. Also, while the ends of this material are sharp, I
find that pre-tinning them removes those sharp edges. Plus,
it makes a nice island of solder that can be reheated to
melt only a section of the whole island, thus making it very
easy to add wires or leads.
Photo 4 shows two soldering islands cut from the
plastic wrap cutting strip.
This project didn’t really need these soldering islands
since only two leads and one piece of wire from the
inductor are the most connected together. However, it did
make soldering them together much easier than getting
the leads of the transistor and LED lined up and then tied
together by the inductor wire and soldered together.
The inductor was then bent back to be above the
transistor and LED before installing it in the small plastic
box. Positioning the parts as well as the entire circuit was
not critical either in relation to each other or in the box.
I completed this project with a small switch and two
battery clips: one for an AA battery and the other for an
AAA battery in parallel so that either size battery could be
used without needing a converter case for the AAA battery
to resize it to a AA battery.
A small amount of “liquid tape” was used to keep the
battery clips and the circuit from moving around. The liquid
tape can be removed if needed to service the circuit in the
future, and it’s strong enough to hold up to normal use.
Photo 5 shows the finished joule thief night light in a
box with the soldering islands hidden under the inductor.
Photo 6 shows the bottom of the box with the
soldering islands visible.
Combining the Dead
Battery 9V Flashlight and
Joule Thief Night Light
This project is simply combining the previous two
projects into one box and making it work with the same
LED. There are many ways to do this. I built two in order to
Photo 5: Joule thief in box with solder islands hidden.
Photo 4: The solder islands’ joule thief.
Photo 6: Joule thief night light with soldering islands visible.
42 September/October 2018