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The printed parts for this project can be found here.

What did I make?

I made a Adjustable Ribbon Generator that takes advantage of low wind speeds to produce electricity. This Ribbon Generator allows for the adjustment of the tension of the ribbon which will allow it to work better in a larger range of wind speeds.

How Did I make?

Using materials bought from the local hardware store I constructed this ribbon generator using a limited amount of tools, and a limited amount of  knowledge on the art of making things. The construction of this ribbon generator is simple enough that almost anyone could build it and start producing energy from the wind!

Where did I make it?

I constructed the whole ribbon generator at my house. the construction took a little over a week and the testing took about a weekend.

What Did I Learn?

There are many things to learn in this project, I for one, finally learned how to properly use an oscilloscope. I learned some new building techniques in the project. And I learned how much fun it was to build things!

For a while I have been researching ribbon generators as a new form of using the wind to generate electricity. The beauty of ribbon generators is that they do not require a lot of wind to work (about 2mph), and they are a really cheap and easy way to generate electricity. Almost anyone can build one. The problem with current ribbon generators, such as the Windbelt is that the ribbon cannot be adjusted for different wind speeds. My idea for this project was to build a ribbon generator that would allow the ribbon to be tightened or loosened for different wind speeds, therefore allowing it to generate more electricity in a larger range of wind speeds.

Right now this ribbon generator requires a person to manually adjust the ribbon. But it should be easy to integrate a servo motor and an arduino to automatically tighten the ribbon generator.

For anybody who doesn't know what a ribbon generator is or how it works, a ribbon generator takes advantage of the aeroelastic flutter effect to generate electricity. I am not going to go into great detail about what aeroelastic flutter is, but it is what causes the ribbon to vibrate when wind passes over it.

To generate electricity, this ribbon generator uses copper coils. For instructions on how to make the coils used in this project, you can refer to my previous project, the coil winding jig.

## Step 1: Materials

Many of the parts used in this project were printed on a 3D printer. The STL files for these prints can be found here.
1. 3/4in x 3 1/2in wood plank. This will be used to construct the wooden frame of the ribbon generator.
2. 1/4in steel rod that will be cut into 4 pieces that will be used for the metal slides.
3. 1/4in hex bolt about 5 1/2 in long.
4. 2 - 1/4in hex nuts
5. 2 - 1/4in ID washers
6. 1 - ribbon about 30in long (Dakron Polyester) the guy at the kite store said this material should work :)
7. 2 - neodymium magnets 3/8in diameter, 1/4in tall
8. assorted screws and washers for assembling the ribbon generator
9. 2 - 1 1/4in OD washers, to be used to affix the scale.
10. 1/8in U bolt, or eyebolt.
For added reference you can download the sketchup file I made of the ribbon generator. The 3D is practically an exact scale model of the real thing, so it can be used to figure out the dimensions of parts.

## Step 2: Step 1 - the Frame

The first photo shows the dimensions of the frame. the frame is built using the 3/4in x 3 1/2in wooden plank. The frame was assembled using wood screws.

The second photo shows the dimensions of the inside wooden planks that the ribbon passes through.

## Step 3: Step 3 - the Scale Side

A digital luggage scale is utilized in this project to determine how much force is being exerted on the ribbon, or how tight it is. the scale is mounted to a printed mounting block by a U bolt. The scale has a strap that was fed through the back of a frame through a small hole. the strap was then fixed to the back of the frame using the 2 -1 1/4in washers.

The steel rods were each cut to 7in each. The were attached to the frame by drilling 2 - 1/4in holes a 1/4in deep into each side of the frame. Then the steel rods were inserted.

## Step 4: Step 4 - the Tightening System

This is where the tightening of the ribbon happens. The ribbon is fixed to the mounting block on the metal slides. the Hex bolt is fit through the mounting block so that the head of the bolt fits flush with the mounting block. the bolt then passes through the frame and a nut and washer are used to fix the bolt, as shown in the second picture. Tightening the nut will pull the mounting block back tightening the ribbon. The opposite happens if you loosen the nut.

## Step 5: Step 5 - the Coils

To learn how to make the coils that will be used to generate electricity please refer to my previous Instructable. The coils will be placed in the printed coil stands. The magnets will then be placed on the ribbon, so that they will pass in and out of the coils.

## Step 6: Testing!

First fix the ribbon between the two mounting blocks on the frame. Then using a fan start the testing of your ribbon generator. I made a wind tunnel out of cardboard to aid with the testing, along with an oscilloscope. Using a set wind speed, tighten or loosen the ribbon until you reach a peak voltage. Make note of the amount of tension on the ribbon using the scale. This is the perfect tension for this wind speed. Hook up the windbelt to an LED and watch it flash with each AC wave.

Participated in the
UP! Contest

Participated in the
Make-to-Learn Youth Contest

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## 10 Discussions

I have been wanting to built one of these for testing. The first thing i want to try was putting coils and magnets on the other end also. In theory if it works on one end why wouldn't it work on the other, doubling your output.

Have you tried running your out put through a rectifier to see what you get in DC?
Have you put enough of these together to get 14VDC under load for charging?

Because this is a resonant system, you don't want to draw too much power out or you'll damp the vibrations.

More important is making sure that the power you do gather is converted efficiently into electricity. Shottkey diodes may not have a low enough voltage drop. Active rectifiers require energy to charge and discharge the gate capacitance, but perhaps prudent selection could solve that.

Putting more coils on it would most likely work as you described. The reason I did not use more coils in the ribbon generator is because I planned to use it for testing, not to produce as much electricity as possible.

I wanted to hook up a rectifier to the generator but I could not find a bridge rectifier with a low enough voltage drop.

I have not tried building one to charge anything yet, but I have a project in the works that should be able to charge a cellphone.

A spring added to the system could make tension more constant with changes in temperature.

How many volts or power is generated with a slow wind or the wind in the video? Is that enough to trickle charge a cellphone or any better than a big solar cell array?

The amount of volts to wind speed is as follows:

2.4 mph - 5.5 volts
4.3 mph - 14.4 volts
5.6 mph - 10.5 volts
7.1 mph - 13.4 volts
8.2 mph - 20.5 volts
9.6 mph - 17.7 volts
10.7 mph - 17.9 volts
18.1 mph - 42 volts

I'm sure you would be able to charge your phone with this in almost any wind speed. Unfortunately I forgot to record the current output, so I do not know for sure what it will charge. It should be more efficient than a solar array because it costs a lot less.

Do you know the resistance of the coils? should be constant, work the current from the voltage and resistance.

what's the frequency that you are getting with the coils? i'm assuming it's something between 30 and 100 hertz?

the freq. ranges from 20 hertz in 2.4 mph wind to 30 hertz in 10 mph wind, and 58 hertz in 18 mph.