Build a Wind Harp!

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Posted in PlayMusic

Introduction: Build a Wind Harp!

About: I like to tinker and experiment with electronics, robotics, programming, and photography. Along with my latest interest in Steampunk.

A wind harp is just what the name says, a harp played by the wind. You don't need lessons with this instrument, just a light wind will do. This design uses four steel strings and two magnetic pickups made with a pair of nails. You can build one with just one string with good results. Mine is 8 feet long, but you can make it as short as 2 feet or as long as you want. I mounted the wind harp on top of a shed and connected the signals from the pickup to my PC inside the house. I broadcast these sounds 24/7 on the internet radio using ShoutCAST. You can hear the wind harp at: http://home.comcast.net/~botronics/windharp.html
I also have some blogs about how to set up your own internet radio station at the above link.

I use Solar Garden lights to power this project, but for this instructable, I'm showing the basic concept of the construction. How you power it is up to you.

Step 1: Make the Support

The wind harp support was constructed from a 2"x2" by 8 foot long pine lumber I just happen to have. Prime and Paint to protect from the elements. Remember, its a wind harp that needs to be outdoors. Although a smaller one can be made to fit a window sill.

I used 1/2 inch steel angles at the ends to support the wires with screw eye bolts. 24 gauge solid steel wire from the hardware store is used for the strings. You can try different thickness for different sounds. Just remember they must be steel or iron, the strings vibrations must interact with the magnetic field produced by the pickup coils, just like a electric guitar.

Step 2: The Magnetic Pick Up

As the wind blows across the strings, vibrations will begin at various harmonics of the strings fundamental frequency. Simply stated, if you puck the string, you will hear the fundamental frequency.
The wind causes multiples of that frequency to vibrate up and down the wire.

To hear the sounds, I use the same method an electric guitar uses to amplify guitar strings. A magnetic pickup is made by winding many turns of # 40 wire on a nail. A magnet is attached on one end to make it magnetic. When this coil is brought close to a vibrating steel wire, tiny voltages are generated and amplified with a preamp. These voltages are connected to my PC sound card. Two are used together to buck out local hum inducing magnetic waves. More on this later.

Each coil was made using a nail. The point on the end is cut off and the nail is chucked on a table top drill stand. Small plastic washers were super glued on the nail to hold the wire in place during winding. I didn't count how many turns were wound, but tried to make each coil about the same. The closer the two are a match, the better the hum bucking. Each coil is held over a string with an angle made of aluminum. Plastic ties hold the coils to the bracket. I wrapped each coil with a piece of rubber hose to deaden vibrations from the frame.

Step 3: Winding Pickup Coils

Wind the coils on the nails with a table top drill press or use a hand drill. I used #40 enamaled wire, but it could be a bit thinner or thicker. Use AWG size 36 to AWG 43. You can get the wire at Stewart-MacDonald. http://stewmac.com They also have kits for making electric guitar pickups.

I haven't actually tried using an electric guitar pickup, but I don't see why it wouldn't work. After all, what you are building is a guitar that is "blowing in the wind". With a guitar pickup, the strings would need to be spaced 1 cm from each other, just like in a real guitar.

The magnets I got from a local Arts and Craft store. Use the super strong neodymium type. You can use just one coil, but it will also pickup surrounding ambient ac "hum". To make it "humbucking",two coils are used. Because the coils are connected with opposing phases, any hum pick up is bucked out.

Notice the magnets on the other coil is reversed. This will cause the other coils pickup polarity from the wire to be reversed. Connecting the two coils in series makes the pick up from the wires to be additive. Just like placing batteries plus to minus in series.

Step 4: Amplifier

To amplify the tiny signal you will need an IC amplifier. A LM386 works will for this project. I made a special pc board, but it can be built on perf board. Keep the amplifier near the coils and bring out your signals using shielded wire to your PC. With my solar powered version, I used the solar garden lights as a housing for the circuit. You can connect the amplifier with a minumum of wiring with 2 conductor shielded wire. The shield can be the common and power negative, while one lead can be power positive and one lead the signal out.

Step 5: Connect to Your PC

After you build the frame, coils and amplifier, its time to test your wind harp. If everything is working, you should hear a loud "twang" when you pluck the steel wire.

For the best harmony, you can adjust the tension on the eye bolts so all the wires are the same frequency. The two inner wires are the strongest performers, while the two outer "passive" wires add some sound through mechanical connection at the single eye bolt end.

You will find that the harp responses to the slightest wind. Higher winds create higher frequencies. To protect the coils from rain, I placed a plastic cup as a cover above the coils.

When it rains, the wind harp becomes a rain harp, making very nice tones as the drops hit the wire.

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    72 Comments

    I can't find the recording. The links you provided on your site are no longer valid. Do you have the recordings elsewhere?

    1 reply

    I have a set of recordings at Soundclick. These were recorded using my latest windharp. Just follow the link.

    http://botsmaker.blogspot.com/2008/04/windsonics-album.html

    How did you fasten the wires at the eyebolts to prevent it from loosening?

    I'm thinking of making one of these between two buildings about sixty feet apart.

    Just for fun, if you have access to any really long guy wires, put your ear up against the wire and tap it. It sounds like a giant reverb or echoplex. (The hundred foot plus guy wires at Burning Man are perfect for this. I do it every year. I'm thinking of taking a mike and small amplifier out there some day.)

    Awww... that stinks... I think it's broken... I'm listening to it right now and I just hear a wind-heard-by-a-cheap-camera noise, not a wind harp. The strings seem to have stopped

    1 reply

    New strings for the new year are blowing in the wind, The windharp is online again.

    Since 2007 and the harp itself still runs. Its gotten better with age. Not really "Live" anymore, its a very long loop that gets played.

    I would love to get an electronic wind harp set up at some point, and use a wind turbine to power all the electrics, keep it in the family and whatnot. I have however converted a broken violin into an acoustic aoelion harp, or an Aeoliolin! http://vulpestruments.blogspot.com/2010/07/aeoliolin.html

    Something else occurred to me, build the wind harp and instead of a regular speaker system, feed it into the TIKI speaker:  Give the TIKI a voice of it's own!



    Would there be a way to construct this for acoustic operation?  So that instead of an amp it would just sound on its own?  It probably would not be loud but that's ok.

    1 reply

    Absolutely yes.  Before electric guitars, wind harps would use a sounding box to amplify  the sounds.  Build a box with a sound hole in it and stretch the strings across it. Size the box to fit inside a window frame and let the wind blow across the strings. Summer is coming, and a wind harp in the window will be a delight during those inviting evening breezes.

    I found this through the Maker Faire. This wind harp is fantastic. Do you find that there's an advantage to magnetic pickups versus under-the-saddle transducer style pickups?

    1 reply

    Since its the wire that is vibrating, that's what I want to monitor. Under the saddle tranducer would probadly pickup vibs from the supporting frame. One problem is hum pickup when using the magnetic pickup.  Good hum bucking techniques are needed with the pickup and amplifier. You also have to keep the windharp away from hum sources.  I haven't tryed a piezo type of pickup. These are well shielded to prevent electrostatic pickup instead of electromagnetic pickup.

    Excellent inst. Nice build.

    I've been listening to you on-line windharp for the last hour or so. It really does give an incredible range of sounds. Did you have a rain shower a while back? The wind seems to have calmed down now.

    1 reply

    My recordings used to be live. Comcast didn't like me "running a server" and would cut my service off. Now I run the station from work. What you are now listening to are live recordings looped together. The wind harp does have an incredible range depending on wind direction, temperature, rain and humidity. I'm always making adjustments of tension and tuning. I now have 3 harps, one of which is 50 feet long. The best recordings are put in the loop.

    Really nice. When listening to your shoutcast feed of the harp it seems like the pickups and amplifier are picking up some AM broadcasts too. There's a background murmur that sounds like detuned voice transmissions. Maybe a ferrite on the wires going to the pre-amp will help.

    3 replies

    no offence, i am no big specialist of electronics, but wouldn't the ferrite block the oscillations produced by the harp too?? i repeat... i honestly know very little of electronics, especially audio processing, but i think analysing the audio output with some software, to determine the average frequency of the noise, and then building a resonating capacitor-coil-circuit to filter it out might be better. i couldn't build one myself, but it's some brainstorming feedback. or you might wanna try and filter the noise out using the computer, to post-process the sound. or even better.... replace the strings with some non-ferrous material, thus not interfering with radio transmissions, and put a very small magnet on it right under the pickup. i think something like compass needles. it should be very small, and light, so it doesn't modify the resonance frequency of the string. but who knows? perhaps it improves it.....

    I did a lot of experimenting with filters and different preamp circuits (see my earlier blogs). I checked the response with a free software oscilloscope program from SillanumSoft. The program is called Visual Analyser 8.0 and works great. http://www.sillanumsoft.org/download.htm
    I have a few movies of the response on my youtube page at: http://www.youtube.com/botronics
    Earlier preamps did pick up some radio stations and a low pass LC filter of 100uH and .005uf worked well. I'm not getting any problems with the LM386 amp at the moment. A ferrite core at the input would be a good Idea just in case. It would have very little effect with the audio frequencies of the wind harp. I've seen some magnetic paints that might work on non-magnetic string, just paint a small section near the coil.

    i am familiar with that software. i recently donloaded version 10.0 after my computer crashed, and tested your live broadcast. just being curious of the frequencies generated. my conclusions were, that the background noise has values around 40-41 Hz, and the sounds produced are harmonics of the 140 Hz sound.... i mean, just roughly measured.... it should be so, assuming that the resonance frequency of the strings corresponds to the frequency of equal wavelength to the string. SOMEBODY CHECK MY ASSUMPTIONS AND CORRECT ME IF I AM WRONG! PLEASE!