Introduction: Diddley Bow

About: I love experimenting with science and physics, especially projects that involve electromagnetism, energy conservation and audio.

A diddley bow, the instrument from which legendary blues musician Bo Diddley supposedly took his name, is a single stringed instrument played with a slide. It first became popular in America in the 1930s, though it's roots can be traced back to Africa. You can see a video of Jack White of The White Stripes constructing and playing one here. I'm sorry I don't have a video of me playing mine, but I'll try to make one soon. The instrument, in its most basic form, is a metal string tensioned between two nails. The string usually lays across a glass bottle or metal can which amplifies the sound. I made the diddley bow in this instructable for a buddy of mine who is a musician, as a Christmas present. I had most of the parts lying around so it only took me about three hours to make, but it can take even less time or much more depending on how fancy you want to be. The one I built is electric, but instead of using a real guitar pickup I made my own (more on that later).


To build one like mine, you need:

A board. The one I used is 32 inches long.

Some nails

A guitar string

A glass bottle

A guitar pickup of some kind

A 1/4 inch female audio port

A scrap piece of wood

A hammer

A drywall screw

Phillips screwdriver

Wood burning kit

Soldering iron

Small gauge rosin core solder

Hot glue gun & hot glue

Step 1: Burn a Design in the Board (optional)

If you have a wood burning kit, you can burn whatever you want into the wood. I printed out a reference, then penciled in the design on the wood, then burned it with the burner. Afterwards, apply a finish to the board if you want to be fancy.

Step 2: Start With a Board

Find a board! Sand it to make it smooth if you want, just don't apply any finish to it yet if you plan to burn designs on it.

Step 3: Put Nails in the Board!

I used nails to stabilize the bottle at one end of the board. First lay the bottle on the board and decide where the nails should go, then remove the bottle and pound in the nail. If you are using a hardwood you might have to drill a small hole for the nail so it doesn't crack the board.

Step 4: Electrify It!

So now that you've made most of the mechanical parts of the bow, either use a real guitar pickup or improvise your own.

Many guitarists, especially the young or uninitiated, may look upon the electric guitar as some kind of black magic. I myself drooled on them without having the slightest idea about how they worked. For this project it will help if you have some idea how pickups work. Electric guitar pickups convert the mechanical energy of vibrating guitar strings into electrical energy. This weak electrical current can be amplified and then pumped through speakers.

In their simplest form, they consist of a coil of copper wire wrapped around a permanent magnet(s). Traditional pickups use thousands of turns of very fine (usually 42 gauge) wire that is wrapped around a plastic bobbin. Six permanent magnets, called pole pieces, are then slid up inside of the bobbin. Because your guitar’s strings are made of magnetic metals (usually steel or steel wrapped in nickel), the parts of your strings above the pickup become slightly magnetized. When you pluck a string, the string and the magnetic field surrounding it vibrate. This induces an electrical current in your pickup’s coil. This is due to the fact that the magnetic field surrounding the moving string drags electrons in the coil with it as it moves. The current generated is alternating current, because the electrons move one way, then the other (just as the string does), creating a voltage that changes polarity. So, the goal is to find a coil of copper wire such as a small transformer, or a solenoid from a relay. You can use this as the coil of your pickup. Then all you have to do is slap a magnet on it and you will have a guitar pickup. For this diddley bow, I found coils that had heavy-gauge copper wire on them and rewound them with thinner wire. I then found small super magnets that fit inside the bobbins, and voila I had pickups. Keep in mind that for the signal from the pickup to be strong enough, you have to have lots of wire in the coil, strong magnets, and the pickups physically close to the string. Either that or use multiple improvised pickups wired together. The possibilities are pretty much endless.

Step 5: Final Touches...

Once you have the pickup, find a scrap of wood to help elevate it to the right height. Also, solder the pickup to the 1/4 inch female audio port so that it can be connected to an amplifier. Polarity doesn't matter because you are working with alternating current. You can have the audio port hanging loose, but it's not really a good idea. So to fix this problem I found a scrap piece of aluminum and drilled a hole in it for the audio port to attach through. Then I nailed the aluminum piece to the end of the board. You can hot glue the pickup in place, and also any wires that might get in the way. Make sure you test everything out before you give a diddley bow as a gift, but other than that mission accomplished. Hit me up in the comments if you have any questions, or just want to show me some love ;). Also please vote for me in the contests!!!!

Step 6: String It Up

Now take your guitar string and attach it to the bow as shown in the picture. Pass the string through the ring on the end, making a loop which you will hook on the nail at the end of the board back by the bottle ( edit: you could also use a screw at that end which might actually work better, as when you tighten the screw it would pull the string down and give it tension). The other end, twist it around itself to make a loop and hook it on a screw or nail at the other end of the board. In order to get the string to have enough tension on it, try hooking up the string and then shoving the bottle underneath it. If it is too tight or too loose, adjust the string and then re-insert the bottle.

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