dynamo

drawing of generator


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CONSTRUCTION
First make the hollow-ended box. Score the cardboard strip like so:

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| 8cm | 3.5cm | 8cm | 3.2cm | 7.7cm |
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|8 | | | | |
|cm | | | | |
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| | | | | |
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| | | | | |
|________________|________|_________________|_______|_______________|


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_____8_________
_|______________ \
|\ 7.7 | \ 3.5
| \3.2 | \
| \_____________|___\
| | 8 |
| | |
| | |
| | | Fold it like this and tape
| | | it securely.
| | |
| | |
| | |
| | |
\ | |
\|__________________|




________________
_|_______________ \
|\ | \
| \ | \ Use the nail to poke a hole
| \______________|___\ perfectly straight through the
| | | center of the box, going through
| | \ / | both sides and all three layers
| | \ / | of cardboard. Then pull the nail
| | \ (hole) | out and use it to widen all the
| | \ / | holes slightly, so when you put
| | O | the nail back through, it will
| | / \ | be a bit loose and able to spin.
| | / \ |
| | / \ | ( You can find the exact center
\ | / \ | by drawing an "X" to the corners
\|___________________| using a ruler. )


At this point you should clamp your four magnets around the nail and give it a spin. This makes sure the box is large enough. The nail and magnets should spin freely. The corners of the magnets should NOT bump the inside of the box as they spin. If the box is a bit too small, start over and make it a little bigger. Either that, or try a thinner nail. (Also, be sure to use the right magnets. Small ones won't work.)

[YES, you can build a plexiglas box instead if you wish. However, don't make it any larger than this. The wire must stay very close to the spinning magnets, so keep the box as small as possible. It should be slightly more than 3 in. wide and slightly more than 1 in. thick.]

Pick the spool of number-30 magnet wire from
_______________ the kit of spools. This is the thinnest.
_|______________ \ Tape one end of the number-30 magnet wire
|\ | \ to the side of the box, then wind all of
| \ | \ the wire onto the box as shown. It's OK
| \_____________|___\ to cover up the nail hole. Pull the taped
| | | end of the wire out, then tape down both
\ | | of the wires so the coil doesn't unwind.
\\ | | You should have about 10cm of wire left
\\\====================| sticking out.
\\\====================/___
|\\====================/ \
-----+-\====================/ \
/ | ==================== \
/ | | | \ Use sandpaper or the edge of a
| \ | | | knife to scrape the thin plastic
| \|__________________| | coating off 2cm of the wire ends.
| Remove every bit of red coating,
so the wire ends are coppery.

(note: the five lines of wire shown above are not real, that's
the 'equals signs' I used to draw with. The real wire can just
be wound up in a big wad in the center of the cardboard box.)

_______________
_|______________ \
|\ | \
| \ | \
| \_____________|___\ Spread the wire away from the
| | | nail hole and tape it in place.
\ | | Stick the nail back through the
\\ | | holes and make sure it can spin.
\\\====================| Take your four magnets, stick
\\\========---=========/___ them face to face in two pairs,
|\\========(\\)========/ \ Then stick the two pairs inside
-----+-\==========(_)=======/ \ the box and on either side of the
/ | ==================== | nail so they grab the nail. Push
/ | | | | them around until they are some-
\ | | | what balanced and even, then spin
\|__________________| | the nail and see if they turn
freely. If you wish, you can
stick 2cm squares of cardboard
between the magnets to straighten
them, and tape the magnets so they
don't move around on the nail.


_____ magnets
|_____| _____________
|_____| |_____________| 2 magnets
=================|| NAIL |_____________|
|_____| ______O______
|_____| |_____________| 2 magnets
|_____________|
SIDE VIEW OF THE
NAIL AND MAGNETS VIEW FROM THE END


TWIST THE WIRES TOGETHER
Make sure that each end of the generator's wires are totally cleared of red plastic coating. If there is a bit of plastic left, it can act as an insulator which turns off your light bulb circuit.

Twist the scraped end of each generator wire securely around the silver tip of each wire from the small light bulb. (If necessary, use a knife to strip more plastic from the ends of the light bulb wires.) One generator wire goes to one light bulb wire, the other generator wire goes to the other light bulb wire, and the two twisted wire connections should not touch together. In the twisted wires, metal must touch metal with no plastic in between.

_______________
_|______________ \
|\ | \
| \ | \
| \_____________|___\
| | |
\ | |
\\ | |
\\\====================|
\\\========---=========/___
|\\========(\\)========/ \
-----+-\==========(_)=======/ \
/ | ==================== |
| | | | |
| \ | | |
| \|__________________| |
| |
\ /
\ twist /
\ {} twist {} /
\ {} {} /
\____/\______ _______/\__/
\_/
( )
( ) tiny
(_) light bulb