HOW TO MAKE THE BANGLADESH TWINE SPINNER

What you need to make the table top version:

2 half-gallon milk cartons string about 8' total (I use nylon mason's twine).

pencil that is full length (about 7") and unsharpened

plastic pen

sharp scissors, tape,

(OPTIONAL) razor utility knife or sharp knife; needle nose pliers or wire hook

Step 1

Punch two holes and cut out two rectangles out of a milk carton.

Print this page and this page.Some browsers--especially Netscape--change the scale and the size of the printed pattern. If the printout says something like, "Scaled-60%" try another browser. Also, the printout has a scale check. It says 2" line to line or 5 cm line to line. Make sure it's accurate. On the two pages, cut out the two identical rectangular patterns on the solid lines save the circle and fan patterns. Carefully fold on the dashed lines.

Tape the patterns on opposite sides of the bottom of the milk carton, and with the spout side of the carton facing one of the patterns, as shown. The bottom edge of the patterns should line up with the bottom of the milk carton.

With a ball-point pen, punch the 4 holes indicated by the circles with a "+" in the middle. Push the pen in to its full diameter. Usually the carton will not buckle if you punch the holes before you start cutting the carton.

With a utility knife, other sharp knife or sharp scissors, cut out the rounded rectangles from each pattern. Be careful not to cut yourself.

 

Step 2

Insert and retain the pen and pencil.

Lay the milk carton down so that the spout side is the bottom. In the top pair of holes insert the pen. I should be a fairly tight fit and not move around. Tape it fast if you have to.

Insert the flat-ended (unsharpened pencil) into the bottom pair of holes. Unlike the pen, it should be loose in the hole and spin around freely. If it does not, make the holes bigger.

While we want the pencil to rotate freely, we don't want it to move sideway very much because it would come out. We can do this the same way they do it in Bangladesh: by making two big bumps of wrapped string. We will wrap two lumps of string (shown in green in the left illustration) just outside of the milk carton. The dashed lines here indicate a "hidden object--as if you had x-ray vision.

To wrap the bump, first center the pencil so the ends stick out about the same amount on each side. Tape (shown as a red square in illustration at right) the end of a 2 foot piece of string to the pencil close to the milk carton. Start turning the pencil so as to wrap up the string. Then wrap tape around it to keep it from unraveling. Repeat on the other side of

the milk carton, being careful not to wrap the string up tight against the carton. The pencil must rotate freely, so make the string wraps close to--but not touching--the milk carton.

Step 3

Rig the remaining string around the pen and pencil

Rigging the string is a bit tricky because space is cramped inside the milk carton. To have access to the pen and pencil from the top and bottom, tape the milk carton down on the corner of a table. Place it so the half of the carton with the rectangular holes is cantilevered (hanging out) over the edge of the table.

Two views of the rigging. The view on the left shows the two halves of the string in different shades of green for clarity.

Needle nose pliers or a wire hook can help extend your reach into the carton to work with the string. Drape the string over the pen and make sure that both halves of the string go to the same side of the pencil (it doesn't matter which side at this point, just both on the same side). Then wrap them once around the pencil, both in the same direction.

Step 4

Add a flywheel and learn how to work the spinner.

Although the spinner will work now, it will work better and you will be able to see how fast it's going if you add a simple flywheel cut out from the second milk carton. With a sharp knife or scissors, cut off the bottom of the other milk carton. Cut on a corner to open it up. Tape on the circle pattern. One of the sides of the carton will have an overlapped seam. Avoid using that side to cut a circle from because the double layer of cardboard will be unbalanced and shake as it rotates.

To punch the holes in the center of each circle, I put the circles on 4 layers of a towel or wash cloth. I use a ball-point pen to start the hole, but pick up the circle and finish it with a pencil because the circles should fit tightly onto the pencil.

To finish the hole with the pencil, I hold the circle as shown and twist the sharpened pencil further and further in (then through your fingers) until it goes all the way on. Because you have already started the hole, you know exactly where the pencil is coming through, so there is no chance of poking your fingers. Try not to bend the circles as you make the holes.

Make at least one circle for the flywheel. More circles will add more momentum to the flywheel. You can reuse the pattern. Push the circles on one end of the pencil. You might have to tape them to the pencil. If using more than one circle, tape them together.

Operating the spinner is easy, but the motion will be choppy at first. With practice, you will learn to make it rotate smoothly without breaks. Holding an end of string in each hand, alternately pull them down. Whichever string you pull down, the flywheel should rotate the same way. You might have to fasten the spinner down with more tape or have someone hold it down.

To make it rotate continuously, actually lift up on the one string while snapping the other string down. It should not stop in between pulls.

The spinner can be used for its original purpose by taping on a hook made from a paper clip to spin fibers. If you know of someone who spins wool, there is a good chance they would like to see your variation of a spinning wheel. There is also a good chance they would show you how to spin a few feet of yarn.

To operate the spinner as a fan, use the fan pattern to cut the shape out of a section of milk carton. Fold on the dashed lines. Fold so that both sides of the propeller curve up (say, if you are using a straight edge to bend it) or both sides curve down (if you are using the corner of a table to bend it). Remove the flywheel and replace it with the fan. The fan blade should curve away from the spinner or you'll blow the air the wrong way. You will probably have to tape on the fan. It moves a lot of air, so it is under a lot of stress.

Although the illustration at left shows the fan spinning clockwise, the correct rotation direction depends on how you bent the fan. If the leading edge in not leading, you will have to wrap the strings around the pencil the opposite way you have them now. That will reverse the direction of the fan.

HOW TO MAKE THE RECYCLED BOOM BOX SPEAKER PHONENote: The extent of this project is two speakers with doubled wire connecting them. That's all! Although I advise how you can extract the speakers from their boxes and several options for connecting the wires, don't lose track of the simplicity of it.

What you need

two speakers

All but the most extremely cheap sound systems have at least two speakers because stereo sounds much better

than mono. Step 1 has some pointers for removing the speakers. If there are several sized speakers in a box, you want the big one, the "woofer."

lamp cord or other wire

Lamp cord is the kind of wire used for most lights. It has two conductors with no ground wire. It might seem like overkill to use such stout wire for the extremely tiny bits or electrical current the speakers will generate. Indeed, you can substitute just about any wire you have around, even much thinner wire. I like lamp cord, however, because it is available in any hardware store or building center, fairly cheap and very strong. Finally, the ample thickness of the copper in lamp cord will conduct the electrical pulses with hardly any "line loss" if you are going really long distances. Old extension cords that you wouldn't trust to plug in anymore will work just fine for the speaker phone.

I think you should have at least 20 feet of wire, and preferably much more. If you are too close to the person you are speaking to, it's hard to tell what sound is coming from the speaker versus what sound comes through the air. But if you are stuck with short wire you can block unwanted noise by having a closed door in between the speakers. There is usually a space under the door where the wire can thread through.

and some of these...

You won't need all of these tools but you might need some, depending on how you get the speakers out of their boxes and how you connect the wires:

* A phillips-head screwdriver will usually open the speaker boxes and dismount the speakers. You might need a long screwdriver to reach the screws imbedded in the box. Or you might have to use a hammer if there are no obvious screws in the boxes.

*Although you can get by with just twisting wires together, wire nuts or a soldering iron and solder will make more permanent connections.

*If you don't have a wire stripper, you can remove wire insulation with a razor or sharp knife.

Step 1

Remove the speakers from their boxes.

If each speaker has its own box, you don't have to remove the actual speakers from the speaker boxes, but your phone

will be more portable if you do. Often there will be 4 screws in the back of the speaker box. Open up the box.

If you can't find screws, you might have to give the box a few whacks with a hammer. Fortunately, the sides are usually are made from thin particle board or plastic, and the back is even thinner. Neither will hold up to a moderate pop with a hammer. Just be careful not to damage the black paper cone in the front of the speaker. The paper is most vulnerable from the front with the fabric covering, somewhat protected from the back, and most protected from the sides.

If the speakers are built right into the boom box, you have to take them out. Try unscrewing screws first before resorting to a hammer.

Step 2

Connect the wires.

Connecting the wires can be as simple as stripping 3/4" or so of insulation from the ends of the existing wires and twisting them together. You might have to cut off whatever jack they have at the end. You can use scissors if you don't have wire cutters because copper is a soft metal.

One of the wires from one of the speakers connects to one of wires from the other speaker. Then connect the remaining two wires. Eventually you will want to screw small wire nuts onto the wrapped connections to make them more durable. The people at the hardware store can show you how to use wire nuts. At least wrap some tape around the bare copper so the wires don't short out, and your phone is ready to go. If the wires are not very long, close a door between you and the person you talk to.

There are two ways to add length to the telephone. You can simply splice more wire in, or you can solder new wire to the tabs on the back of the speaker. Soldering irons are cheap and it's worth learning how to solder, though that's beyond the scope of these directions. You can learn it from a book or a web site, but it's best to find someone who can show you how.

Step 3

Use it!

Before you speak into it, you can make sure the connections are ok by putting one of the speakers face-up and putting into it uncooked rice, un-popped popcorn, bits of rolled-up paper balls--anything small that will bounce around. Now tap on the black paper cone of

the other speaker. You should see the little bits of stuff jump every time you tap the other speaker.

Using it to communicate is pretty straightforward if you keep the following things in mind:

*Get the speakers far enough away from each other so you can't hear voices transmitted through the air. A closed door in between helps.

*Speak loudly right into the speaker.

*Go for a balance of speaking and listening, not all one or the other. Learning to say "over" when you are done speaking helps.

*Keep the speaker on your ear when listening.

My twin sons in different rooms use a double set of speaker phones so they

don't have to keep switching over.

 The instructions below arefor a design of perscope made from poster board or cereal box for the body, and the mirrors are cut from ordinary CDs or DVDs. If you are going to be making lots and lots of periscopes, I have another set of instructions that use plastic mirror here. Also, the Exploratorium has a design of periscope that uses a milk carton and small cosmetic mirrors here.

Step 1

Cut the mirror

We can thank Shannon of Victoria BC, Canada for the idea of using ordinary CDs for the two mirrors. You can cut the CDs two ways: the proper way is with a vice as shown by pictures sent by Shannon. She wrote, "Pictures of the process for cutting CD's is below. Each CD makes four mirrors. Just keep bending the CD slightly as scoring and it will cut/break clean pretty quickly." If you forget to keep scoring as you bend, the CD will

shatter and ruin the reflective surface.

If you don't have a vice, or if you are lazy like me, you mght be able to just cut them with a high-quality pair of scissors. When I first tried it, some of the CDs would shatter, but then yet another Canadian, Heather Dickey of Ontario, (who made the periscope project with here cub scouts) wrote in that warming the CD up first with a hairdryer eliminated the shattering problem--and it worked! And then I found that heating them in warm water works too. From this I deduce that heating many materials makes them less brittle and there must be lots of intelligent, creative women live in Canada!

Step 3

Cut out the periscope body and the triangle mounts.

Click here and print out the body pattern. Some browsers--especially Netscape--change the scale and the size of the printed pattern. If the printout says something like, "Scaled-60%" try another browser. Also, the printout has a scale check. It says 2" line to line or 5 cm line to line. Make sure it's accurate. Rough cut (bubble cut) around the solid lines and stick 4 tape "doughnuts" to the corners of the non-print side. Tape it onto the cardboard and cut out on the solid outside lines. Keep the pattern taped on until you have folded on the dashed lines in the next step.

 

Go here and print out the pattern for the triangle mounts. Some browsers--especially Netscape--change the scale and the size of the printed pattern. If the printout says something like, "Scaled-60%" try another browser. Also, the printout has a scale check. It says 2" line to line or 5 cm line to line. Make sure it's accurate. The illustration only shows one, but you'll need to make two. When formed into the said triangles, they will hold the mirrors in the periscope at just the right angle. Once again, rough cut them out and stick them onto cardboard using tape doughnuts. Cut out on the solid lines (next step). Don't tear off the pattern until it is folded in the next step.

 

Step 4

Fold and tape

Fold both the periscope body and the triangle mounts on the dashed lines. Do it with a straight edge or on the sharp edge of a desk. Kids have a hard time applying enough pressure to make the fold while at same time trying to be accurate and stay on the dashed line. For that reason, I encourage the kids to help each other out in pairs for this operation. Four hands are better than two. Also, Laurie Spurk, a teacher and Bible camp leader suggests "...if you put a ruler on the dotted lines and then trace it (pushing hard) with a pen your lines will fold easier."

 

When folded, the body will start look like a rectangular tube. When you're satisfied of the folding job, tear off the pattern and tape the edges together.

Similarly, fold the triangle mounts on their dashed lines and they will actually start to look like triangles. Tape one end to the other end.

Step 5

Tape the mirrors to the mounts, and the mounts to the periscope.

The mirrors have to be taped to the hypotenuse of the triangle. This is the longer side opposite the taped ends. The triangles are right triangles (have a 90 degree angle), isosceles (have 2 sides of equal length) and they have two 45 degree angles.

Stick tape donuts to the back side of the mirror or CD, or stick it onto the hypotenuse of the triangle and attach the mirror.

 

 

On one of the other sides of triangles, stick on a tape doughnut. Push that side of the triangle into the periscope so it sticks on the inside wall. Look carefully to see how it goes in. Put a piece of on the bottom to further secure it in place. Of course, this has to be done with the other triangle on the other end as well.

Tape in both mirrors, one to each end of the periscope.

You might have to do some adjusting to get the mirrors to line up, but it's pretty intuitive.

I doesn't look like a high-tech speaker but it works well. I didn't expect a high quality of the sound from this made-from-scratch speaker but it performs very well, better than I expected.

A speaker is just a magnet, a coil, frame and a cone or any material that can make the air vibrate. Here is the bill of materials that I used to build this speaker:

1 Magnet (neodymium magnet works great) 1 Business card Wire 32 or 34 AWG (you may use 30AWG) Paper bond Tape Glue Scissors Ballpoint pen Lego bricks or wood. Ruler.

Cut two long pieces of paper vertically, half inch wide. (0.5 inches by 11 inches).

Roll one strip of paper over the magnet. Use some tape to keep it but DO NOT put tape on the magnet. The Cylinder needs to be removed from the magnet, so do not tape the paper to the magnet.

List of materials

cut paper strips

roll the paper.

Roll the second strip of paper over the first one. Do not glue or tape each one with the other. Roll it individually.

Use tape to keep the paper as cylinder.

Using the ballpoint pen, Draw three lines on each side of the business card. There is no exact measure but try to draw the lines at least half inch away from the corners (0.5 inches)

Fold the business card using the lines as reference. The lines will help to fold it.

roll another paper

Draw lines.

fold the card

Remove the magnet and glue the paper cylinders at the center of the business card. Using instant glue or hot glue works ok.

Once the glue is dry, put the magnet back inside the cylinder and start making the coil.

I do not recommend to use wire AWG 30 as it needs a lot of loops. Using AWG 32 or 34 will need about 40 to 50 loops. After you finish winding the wire, use some tape to secure it.

Do not try to make the coil without attaching it to the business card, it is an almost impossible task.

Make the frame approximately the size of the business card and not higher than one inch.

I used Lego bricks because I had some handy. Wood may work better. Try not to use any metal that can be attracted by the magnet.

Put some glue on the magnet when it is inside the cylinder. On this step, Hot glue works better than instant glue. Be sure the glue doesn't touch the paper cylinder.

glue the cylinder

make the frame

Put glue on the magnet.

Assemble the speaker and let the magnet to fall and glue itself to the frame. It will allow to have the magnet exactly on the center of the coil. Wait until the glue dry.

Once the glue that attach the magnet to the frame is dry, remove the business card and the coil. Try not to disturb any piece on the frame or the business card.

Now, remove the inner cylinder. Is ok to break it as it will discarded. Try not to damage the secondary roll [or paper cylinder].

The last step is to put back the coil to the frame. The coil should not touch the magnet and should move freely.

I did connect my home-made speaker to my laptop and here is how it sounds like:* WAV File, 1MB

6/17/2007 Update:

I did a modification to my homemade speaker and it improved the volume of the sound. A simple disposable [plastic] cup amplifies the sound mechanically. The sound is amplified because the resonance of the plastic cup.

assemble the speaker

almost done

remove the inner cylinder

Once the "Speaker" is assembled, cut a hole on the business card. (see next photo)

Glue the coil to the bottom of the cup instead of the business card.

Glue the plastic cup to the business card and that's it! Now it looks like a real speaker, a home-made speaker, just built from scratch.

How it works?

The coil generates a magnetic field when electricity is applied to it. The magnet attracts or repels the coil and makes it to move. The vibration generates the sound that we hear thanks to the air.

Most of today speakers have a resistance of 8 ohms. This homemade speaker may have less than 8 ohms and may not be able to make loud sounds but basically it shows exactly how it works.

homemade speaker

bottom of speaker.

Using different materials, may cause the sound to change, even to make it louder. I will work on another design to find which one works better. I will work to make an easy and better design...

... someday. That day was August 6, 2007. I created a "Hi-fidelity Homemade speaker." Check it out: /other_projects/index.php?homemade-hifi-speaker.jpc

3/13/2008 - Update: If your speaker sounds Horrible, check:

The wires should move freely. The cards should be completely glued to the cup. The coil have no loose wires. Try to keep the coil tight enough and secure it with glue or tape. Loose wire may vibrate and cause distortion. The coil should not touch the magnet. Try to make the coil wider. Also, the coil should not touch the LEGOs.

The sound is too quiet? No sound?

Be sure the coil have at least 50 turns or, if you have a multi-meter, more than 7 ohms. Adjust the height of the coil in reference to the magnet. Use only neodymium magnets. Some personal or portable audio devices doesn't have enough power to drive a speaker. Try many audio sources if you get no sound or the volume is low. Also, you can try this simple circuit: Mini Amplifier with LM386

***WARNING*** DO NOT use AWG 24, 26, or 28. You need to use AT LEAST AWG 30. The wire should be isolated! Again, it should have a coating. Do not use any other kind of wire as it may short-circuit the audio output.