Friday, July 27, 2007

Wind Harp Live!

Its not too difficult to add live audio to your own web page. You will need to get Windows Media Encoder, a free program found here. To broadcast the sound on the internet, I connected the harp to the microphone input of my PC and run Windows Media Encoder. A good tutorial on setting up live broadcasting can be found here. For the listener to hear the harp, I made a web page to launch Windows Media Player using the HTML code example found at this webpage . If it is windy and I actually have Windows Media Encoder running, you should be able to connect by going to My Wind Harp page.
You can learn more about my wind harp project by viewing some of my earlier blogs about the subject.

Saturday, July 21, 2007

Simpler Solar Powered Preamp

Usually the best solution is the simplest solution. I'm using a LM386 now for the preamp in my Wind Harp. The LM386 has low power needs and has good tonal quality, plus its use as a preamp is simple and efficient. I will also use two solar garden lights wired in series to supply power. To draw power from the solar lights just simply connect a set of leads from the the battery holder terminals. Bring out the wires and connect in series. Below is the schematic and photos of the solar lights.

The schematic of the preamp using the LM386 and two garden lights.

Remove the screws that hold the two halves of the garden light together. Solder wires to the battery holders inside the garden lights and connect in series.

Closeup showing circuit board (perfboard), connectors for power, input and output. Hide all this wiring inside the bottom bowl of the garden light.

For more info about garden lights and how they work, visit "Garden Light Autopsy" at my website here. Or get the pdf here.

Friday, July 20, 2007

Improved Preamp for Wind Harp

I did some changes to the wind harp preamp, some of which Acme Fixer (see previous blog) suggested. Moving the preamp at the harp also reduced a lot of the 60hz pickup. I posted at You Tube a video of the waveform as shown by Visual Analyzer 8.

View the YouTube video here.

Improved circuit:

Saturday, July 14, 2007

Preamp for Wind Harp

I built a preamp circuit for use with the wind harp. The amplifier uses a J-fet transistor to connect to a magnetic pickup without loading down the pickup too much. The rest of the circuit brings up the gain enough to drive a set of Amplified PC Speakers.

Bread boarded circuit while in the design phase. That mess really works!

The preamp can also be plugged into the microphone input on a PC. Dual coil design is next to test out as a method to buck out hum. Right now, I'm just using a single coil with a magnet as the pickup. The circuit is still a "work in progress" and has not been finalized. I will post the final tweeks when done.

You can download a pdf of the schematic HERE

I also made a Youtube video of the waveform. View it HERE
The video shows a predominate frequency at about 440 hz and low frequency ripple from hum and vibration of the mount. When a truck drives by it will increase. More work on the preamp can be done to remove this.

You can listen to the harp "Live", if I have Windows Media Encoder on. Just open Windows Media Player, click "File","URL" then copy and paste this URL:

I used a freeware oscilloscope/FFT program to view the signal. Get it HERE

The author of Watson's eBlog has been very helpful in my design of the preamp. He also has an excellent design of a preamp of his own for bringing the sounds of the outdoors inside. The site can be found HERE

Saturday, July 7, 2007

Wind Harp Experiments

After reading a lot about wind harps and hearing the awesome sounds they make, I decided to give it a try. I strung a steel wire between two "C" clamps separated by almost eight feet. The support is a 2" by 2" by 8 feet long pine stud I got from Home Depot. Each C clamp has a hole drilled on the side with a eye bolt installed to support the wire. The eyebolt is tensioned untill a nice tone is heard when plucked.

Photo on the left show pickup placed near the wire.

Photo on the right show the whole thing, about 8 feet high.

So I don't have to use a sounding board to make the sounds audible, I used a magnetic pick up and a Radio Shack amplifier to amplify the delicate vibrations. As the wind "plucks" the string, musical notes and harmonic vibrations could be heard.

A 3 inch C clamp holds the wire on each end.

You can hear what my wind harp sounds like at this link.

The Harp I made just uses one string to prove it works. Now imagine using several strings.

Wednesday, July 4, 2007

Wind Harps

I found an interesting wind harp design at this website . Wind Harps or more correctly called an Aeolian Harp is played by the wind. The wind causes the string to vibrate and if several strings are tuned to the same pitch, these sounds reinforce and modulate between themselves. The resulting sounds create a serene and peaceful melody. Such an instrument can be made with PVC pipe and nylon fishing line. The above website has a list of materials and full instructions on how to make one.