Introduction: Simple Telegraph Key and Sounder
A while ago I built a telegraph machine and was amazed by the simplicity and the joy obtained from pounding out my name hundreds of times. When I saw that the weekly challenge was magnet themed, I knew that I had to make an instructable. I was able to build it in an hour while taking pictures, and I bet it could be done in about 30 minutes. Telegraphs are simple communication devices using a switch operated at one station to control a electromagnet at a separate telegraph station. The electromagnet then will pull down a piece of steel for a short time or a longer time (dot or dash). It was used in the U.S. civil war and as used as a major communication device from the early 1800's until the mid 1900's. Now let's go make one!
Step 1: Materials
These Items can be found in any workshop or hardware store and are pretty basic:
Scrap wood (Plywood and a board about 3 inches high)
A nail a little taller than your board of wood
Some sheet steel (thin)
Insulated or magnet wire
9v battery and holder
assorted nails and screws
Saw (If you need to cut the wood)
Step 2: Wooden Bases
The base for the sounder is a piece of plywood attached to the 3 inch (or so) wooden board. The Board should be a bit shorter than the nail that you are using for the electromagnet. The base for the key is just a small piece of plywood.
Step 3: Making the Key
To make the key drill a hole through your bottle cap, piece of copper, and into your wooden base. Then, put the screw through the copper, then the bottle cap, and lastly into the wood. To finish your key put a nail in your base where the end of your copper piece so that they hit when you press on the copper.
Step 4: Electromagnet
Take your nail and wrap about 10-20 feet of insulated or magnet wire around it. If you have a thicker piece of steel you will need to wrap more wire around the nail. The more wire, the more strength the magnet will have. If your telegraph doesn't work at first, I would try making your magnet stronger.
Step 5: Make the Sounder
Attache the nail to your sounder base with your hammer. Then take a thin piece of steel ( from a cookie or popcorn tin) and nail that to the top so that it hangs over the edge and above the electromagnet. You want your piece of steel about a mm away from the electromagnet so that it will be able to bring the steel down. This will take a lot of bending to get it just right, but it is necessary.
Step 6: Wire It Up
Now you have to wire it up, you can make the wires as long as you want up to a couple hundred feet. Any longer than that and you will have to have batteries at regular intervals along the wires.
Wire it like this:
Electromagnet to screw holding the copper to the bottle cap
Nail on key to battery holder +
Battery holder - to electromagnet
Now you're done! Look up Morse code and then pound out your name in dots and dashes for hours. If you haven't already figured it out, press the copper piece down until it comes in contact with the nail. This should result in the electromagnet attaching to the piece of steel.