Features

Copy + Paste

The main feature of the device is to perform two keyboard macros:

1. Copy (Ctrl+C)
2. Paste (Ctrl+V)

It does this by appearing as a USB HID keyboard, and doesn't depend on any special software on the PC. So it should work with any device that supports a USB keyboard and has copy and paste mapped to Ctrl+C and Ctrl+V.

To perform the copy action, you do a long press on the key. (Think of a Morse code dash.)

To perform the paste action, you do a short press on the key. (Think of a Morse code dot.)

This setup means you can copy something and then paste it many times, very quickly.

Silent Mode

The default behavior is for the buzzer to make a sound when you perform the copy or paste action. I used a passive buzzer so it can do different tones. This is quite funny, but also serves an important purpose of letting you know you've held the key down long enough to perform the copy action.

But there's also a problem with this feature: other people find it annoying for some reason to hear beeps coming from my desk all day.

I could have addressed this using an on-screen notification on the PC but I really wanted to avoid making any special software. I also considered things like flashing the scroll lock key on the keyboard but that means looking down from my screen...

So instead I also made the telegraph key appear as USB HID mouse. Most of the time it doesn't do anything, but when you do a copy, it makes the mouse pointer do a little jump. It moves quickly in a small circle, returning to where it started. I'm usually looking at my cursor while I'm operating the key, so this worked really well. On Windows at least, this does not affect my mouse if I happen to be moving it at the same time.

You toggle Silent Mode with a very long press, which is accompanied by a confirmation beep.

Note: After using the key for a while I've found I don't need this feedback anymore since I've just got used to how long I need to hold it for copy.

Main Menu

Again, I really didn't want to make an app to go on the PC and tie this thing to specific platforms. So how do I implement a main menu?

Easy, you open up Windows Notepad or equivalent on the PC, then hold down the key while connecting the USB cable.

The key then types out its main menu into Notepad, and you use a long press to change options. At the moment the only thing you can change it to is Morse trainer mode. The change is saved to flash memory, then you unplug and plug it back in to start up normally.

[TODO: Video to go here]

Morse Trainer Mode

I thought it was a bit of a shame if the key can't be used for Morse code anymore, so in Morse Trainer Mode, it just operates the spacebar. ChatGPT claims that Morse training software on the PC typically uses spacebar so it ought to work with any of those.

Hardware

Hardware wise, this project is dead simple and would be suitable for a beginner.

I used:

• An old Soviet-era telegraph key that I bought from https://www.ebay.co.uk/str/dentalodessa in Ukraine (not affiliated or sponsored).
• A Tiny 2040. I used this because it's small enough to fit into the telegraph key's base, but it's wildly overpowered for this simple application so you can use something else if you prefer.
• A passive piezo buzzer: https://www.ebay.co.uk/itm/266509085969
• A USB C cable. I chose a braided type because it looks nicer. Make sure yours has data lines as well as power connected!
• Solder, heatshrink, zip ties, hot glue etc. that you probably already have.

I didn't need to modify the key mechanism, although I did replace the disc under the knob with this because I didn't like the look of the original fibrous disc. I simply tapped the new hard plastic disc and it screwed on to the original knob's screw.

You don't need to use the same model of telegraph key - in fact, any momentary switch works. But the point of the project is to use a telegraph...