This is an instructable on how to make a small, portable morse code practice keyer that you can put in your pocket, take anywhere and practice learning Morse Code. It is composed of only two components and takes about half an hour or less to make. I have taken a keychain tone generator, used for tuning musical stringed instruments, and simply added a contact switch between the tone generator circuit and it's speaker. Very cheap, portable and useful for learning Morse Code. Watch the video to see how it works.
Step 1: Open tuner case and solder in wire to speaker
First step is to find a music instrument tone generator - that can be found at music stores and online. They should run about ten dollars or less. You could just build this keyer from scratch with a piezo buzzer, battery, switch and case but the cost will be more than adapting a keychain tone generator which has all the components except the keying switch built in.
Your tuner probably won't look like mine but the keychain tuners are all similar.
Open the case.
Unsolder one of the wires leading from the oscillator circuit to the speaker. Route that wire outside the case through a small hole you have to file or drill in the side of the case.
Solder another short piece of wire to the speaker terminal that you just unsoldered. Lead that wire outside the case also.