PEAK AMP — MIC LEVEL — dB CTX —

PEAK FREQ — Hz LOCK — Hz DET WPM —

IN-BAND — dB OUT-BAND — dB RATIO — dB

BRIGHT — DARK — CONTRAST —

FPS — DET WPM — RES —

DOT µ — ms DASH µ — ms SIGNAL —

SYMS (ms) —

GAPS (ms) —

STATUS init

About

Morse code turns every letter into a short pattern of short and long beeps: dots and dashes. Samuel Morse and Alfred Vail built it for the electric telegraph in the late 1830s, and for the next hundred and fifty years it carried news, orders, distress calls and radio chatter around the world. Ships used it until 1999. Radio amateurs, pilots checking navigation beacons and anyone with a flashlight still do.

This trainer teaches it by doing. Every tap walks a path through the code tree on screen: a dot steps one way, a dash the other, and the letter you've reached lights up. It can also listen: point your microphone at Morse audio, or your camera at a blinking light, and it decodes as it goes.

The timing

One unit is the length of a dot. A dash is three units. The silence inside a letter is one unit, between letters three, between words seven. At 12 words per minute a dot lasts 100 ms (1200 ÷ WPM).

What each control does

DOT · DIT and DASH · DAH

Add a dot or a dash to the letter you're building. Pause, or press ↵ LETTER, and it's added to the decoded strip.

HOLD · KEY

A straight key, like the real thing: the tone plays while you hold it. A short press is a dot, a long press a dash, and the trainer learns your rhythm.

Keyboard

↓ dot, ↑ dash, Enter finish the letter, Space word space, Backspace delete, Esc clear. Type letters, numbers or punctuation to hear them in Morse.

␣ SPACE, ⌫ BACK, ✕ CLEAR

Add a word space, delete the character before the cursor, or start over.

Decoded strip

Everything decoded so far. Tap anywhere in it to move the cursor and insert there.

Code tree

Every letter sits at the end of its dot-and-dash path. The path you're keying lights up. On a phone, swipe it sideways.

▶ REPLAY

Plays the whole decoded strip at the current speed, highlighting each letter as it sounds.

💾 EXPORT

Saves the decoded strip as a WAV sound file.

🎤 LISTEN

Decodes Morse from the microphone. It finds the tone (300 to 1200 Hz), locks onto it, and learns the sender's dot and dash lengths. The panel shows PEAK FREQ, the LOCK it's following (↻ resets it), the detected WPM, and how far the tone stands above the noise.

📹 WATCH

Decodes a blinking light with the camera. Tap the light in the picture to track it.

WPM and HZ

Sending speed, 5 to 30 words per minute, and the tone's pitch, 200 to 1500 Hz.

🔊 AUDIO and 💡 LIGHT

Where the code goes out: the speaker, the whole screen flashing, or both. A second phone on WATCH can read the flashing screen.

How to use it

Learn the sounds, not the dots. Morse is a rhythm. Say the letters aloud as you key them: A is “di-dah”, N is “dah-dit”. Counting dots and dashes stalls past a few words per minute.

Start small. E (·) and T (−) are one symbol each. Add I, A, N and M, then S, U, R, W, D, K, G and O. The code tree shows how each letter grows out of the ones above it.

Keep the characters fast and the gaps long. Learn each letter at 15 to 20 WPM so it sounds like a word, and slow down by leaving more space between letters rather than drawing them out.

Decode a friend. Put one phone on LISTEN and key on another, or turn on LIGHT and point a second phone's camera at it on WATCH.

Sharing a message

Press Share (top right). The message starts as what's in the decoded strip; type or edit it there in the box. Choose whether the share page shows the words or keeps them secret. Each share gets its own page and picture for Facebook and other link previews.

A secret share is a copy-by-ear challenge. Your friend's trainer loads your speed and tone, plays the message, and lets them key in what they heard, then Check my copy scores it. Reveal shows the answer.

The Signal Stack

Three machines for sending words without a voice, oldest first. Each one solves the same problem, getting letters through a noisy channel, in the way its era could.

Discover more Oddities at odd.placeGenerative art, games, science toys and signal machines from the same workshop.

Made by Jason Buchheim. Produced by Odyssey Expeditions, marine biology adventure travel since 1995. Everything runs in your browser; your microphone and camera never leave your device.