Morse Code Machine: Online Simulator & Practice Tool
Step up to a virtual telegraph key. Tap for dots, hold for dashes. The simulator measures your timing, plays audible feedback, and decodes your transmission in real time. The dash threshold is adjustable, so it works for both new learners and experienced operators.
Tap for a dot, hold for a dash.
Or press the Space bar.
The History of the Telegraph Key
The telegraph key, sometimes called a straight key, bug, or paddle depending on the design, was the primary input device for Morse code communication from the 1840s through the late 20th century. The earliest keys were simple spring-loaded levers: press down to close the circuit, release to open it. Each closure produced a single click on the distant sounder, and operators learned to read the duration of those clicks as dots and dashes.
By the 1880s, the so-called “American” straight key had become the standard: a horizontal lever with a knob on the operator's side, pivoting on a fulcrum, with adjustable contact points. Operators developed a distinctive wrist-and-finger technique called fist. Every operator's fist was slightly different, and experienced Morse operators could identify individual senders by their timing alone. A clean, rhythmic fist was prized; a choppy or irregular fist was the mark of a beginner.
Later innovations included the bug (a semi-automatic key with a vibrating pendulum that produced dots automatically) and the electronic keyer with twin paddles (one for dots, one for dashes). The straight key remains the simplest and most direct way to learn Morse, and that is what this online simulator emulates.
Learning to Send Clean Morse
The hardest part of learning to send Morse code is developing a consistent sense of timing. A dot must be exactly one unit long. A dash must be exactly three units. The gap between symbols within a letter is one unit; between letters, three units; between words, seven units. Anything off, and the receiving operator has to work harder to copy you.
The Morse Machine helps you build this timing sense by giving you instant feedback. Set the dash threshold high (300 to 400ms) when you start, so you have plenty of time to decide whether each press is a dot or a dash. As your reflexes sharpen, lower the threshold toward 150ms and try to send at faster speeds.
A good practice routine: start with simple letters (E, T, I, M, S, O, all dots or all dashes), then move to letters that mix the two (A, N, R, K). When you can send the alphabet cleanly, try short words like CAT, DOG, and HELLO. The decoded text panel will tell you immediately if your timing was off. If you see a wrong letter, replay the symbol and adjust.
Keyboard Shortcuts
Hold to key the telegraph. Quick press = dot, long press = dash.
Delete the last symbol from your current letter.
Commit the current letter and start a new word.
Morse Machine FAQ
How does the telegraph key simulator work?+
Click and hold the large circular key, or press and hold the Space bar. The simulator measures how long you held it. If you held it for less than the dash threshold (default 180ms), it counts as a dot; if you held it longer, it counts as a dash. The tool also detects letter gaps and word gaps based on the timing between taps.
What is the dash threshold and how do I set it?+
The dash threshold is the minimum hold time, in milliseconds, for a key press to register as a dash instead of a dot. Lower thresholds (100 to 150ms) suit fast, experienced operators. Higher thresholds (250 to 400ms) work better for beginners who need more time to commit to a dash. Adjust it until your dots and dashes register reliably.
Can I use my keyboard instead of clicking?+
Yes. Press and hold the Space bar to key the telegraph: tap quickly for a dot, hold for a dash. Backspace deletes the last symbol from your current letter, and Enter commits the current letter as a word break. This makes the tool fully usable without a mouse.
How does the simulator detect letter and word gaps?+
After each symbol, the tool starts a timer. If you do not press the key within 3 dot-durations (the standard letter gap), it commits the current letter and decodes it. If you wait an additional 7 dot-durations (the standard word gap), it commits a word break. This mimics how real Morse operators separate letters and words without explicit separators.
Does the tool play sound for each symbol?+
Yes. When sound is enabled, the simulator plays a pure tone for each dot and dash you send. The tone duration matches the symbol length (1 unit for dots, 3 units for dashes) at your current WPM setting. You can mute the sound with the Sound toggle if you prefer silent practice.
Can I use this on mobile?+
Yes. The large key button is touch-friendly and uses pointer events, so it works on phones, tablets, and desktops. On mobile you will not have a Space bar, but the on-screen DOT and DASH buttons (or the big telegraph key) work the same way.
Ready for Structured Practice?
Once you can send clean Morse, head to the practice trainer for guided exercises with scoring, streaks, and accuracy tracking.