Tapping and blinking: Morse code without any equipment
You can send Morse code with anything that gives two signals someone else can tell apart. A hum, a whistle, a closed eye or a press of the hand can be short or long, exactly like a radio tone, so a dit is short and a dah is three times as long. A tap or a knock has no length, so for tapping you need another way to tell them apart: one tap for a dit and two quick taps for a dah is the simplest.
The code itself does not change. What changes is how you show the difference between a dit and a dah, and how you make the silences between letters and words clear enough to read.
Signals that last, and signals that do not
Morse was built for signals with length. A dit is one unit, a dah is three, and the gaps are one unit inside a letter, three between letters and seven between words. Anything you can hold, you can send in standard timing:
- Humming or whistling. Short and long sounds, like a sidetone.
- Blinking. A quick close for a dit, eyes shut about three times as long for a dah.
- A press or a squeeze. On someone’s hand or arm, short and long.
- A scrape. A fingernail drawn along a table makes a sound that lasts as long as you keep drawing.
A knock or a tap is over the instant it happens. Tap “long” and nobody can hear the difference. So taps need a code of their own for the dah.
Tapping and knocking
There are three good ways to tap Morse. Pick one and agree on it with the other person first.
One tap for a dit, two quick taps for a dah. This is the easiest to learn. The two taps of a dah go close together, like “ta-tap”; the pause between one element and the next is clearly longer; the pause between letters is longer again; and a word gap is a long silence. The trap is the middle gap: if your elements run together, a dit and a dah blur into three taps. Keep the double tap quick and the pause after it steady.
Two different sounds. A knuckle tap for a dit and a flat-palm thump for a dah, or a tap on the table top for a dit and on the edge for a dah. Every element is one sound, so timing is easier, but the listener has to hear the difference in tone, which is harder through a wall.
A tap and a scrape. Tap for a dit, drag a fingernail for a dah. The scrape has real length, so this one sounds closest to proper Morse up close.
Here is OK with one and two taps. O is ---, three dahs, so three double taps with a pause after each. K is -.-, so a double tap, a single tap, then a double tap. Leave a clearly longer silence between the O and the K.
| Letter | Code | One tap / two taps |
|---|---|---|
| E | . |
tap |
| T | - |
tap-tap |
| A | .- |
tap, tap-tap |
| N | -. |
tap-tap, tap |
| I | .. |
tap, tap |
| M | -- |
tap-tap, tap-tap |
A knock carries through a door, a wall or a table, which is what makes tapping useful when you cannot see each other. If you have heard of a “tap code” that counts knocks to find a letter in a grid, that is a different system, not Morse, and the two cannot be read the same way.
Blinking
Blinking Morse works when the other person can see your face clearly, up close or on a camera. A dit is a quick, deliberate close of both eyes; a dah is eyes shut for about three times as long, a second or so while you learn; and between elements your eyes stay open. Letter gaps and word gaps are longer stretches of open eyes.
The difficulty is that everyone blinks without meaning to. Two habits help:
- Make every signal firm. Squeeze your eyes shut for a dit rather than flicking them, so a deliberate dit looks different from a natural blink.
- Go slowly and look straight ahead. A slow, steady pace lets the watcher ignore stray blinks, and looking at one point keeps your face still between signals.
A famous example is from 1966. Jeremiah Denton, a US Navy pilot held as a prisoner of war, blinked T O R T U R E in Morse during a televised interview. In Morse that word is - --- .-. - ..- .-. .. Stories of that kind are told in famous Morse code messages.
Humming, whistling and touch
Humming is the nearest thing to the tone you hear on the radio, and a good way to practice. Hum the rhythm words as you go: A is di-dah, B is dah-di-di-dit, and the sound of each letter sticks better than a picture of its dots and dashes. Humming reaches across a quiet room, no farther.
Whistling carries much farther than humming, and short and long whistles are easy to tell apart. It works across a garden or between rooms, as long as the other person is listening for it.
Touch is the private one. Press on someone’s hand or forearm, short for a dit and long for a dah, and let go for the gaps. Nobody else sees or hears anything, which is why it suits secret messages for friends and family. It needs a light, even touch: a heavy press is hard to time.
What works where
| Method | How far | Needs | Who notices |
|---|---|---|---|
| Touch | Arm’s length | Contact | Only the two of you |
| Blinking | Across a table, or on camera | A clear view of your face | Anyone watching closely |
| Humming | Across a quiet room | Quiet | Anyone nearby |
| Tapping or knocking | Through a wall or door | A hard surface | Anyone in earshot |
| Whistling | Across a garden | Open air or an open door | Anyone in earshot |
| A flashlight | Across a field at night | A light and a clear line of sight | Anyone who looks |
For the last row, how to signal Morse code with a flashlight covers timing a light and reading one at a distance. Never point a light at anyone’s eyes, or at vehicles or aircraft.
None of these methods replaces a call for help. If anyone needs help, call your local emergency number first, wherever you can; a signal can add to that call, never stand in for it.
Agree before you start
Without a radio’s steady tone, small agreements make a big difference:
- The scheme. One tap or two, two sounds, or a scrape. Mixing them mid-message ruins it.
- A start. A few quick taps, or a long press, to say “a message is coming”.
- Over and received. K,
-.-, means “over, your turn”; R,.-., means “received”. Both are short in any medium. - A correction. The error signal is eight dits,
........: eight single taps, then send the word again. For blinking, eight dits is a lot to watch, so agree on something simpler, like a pause and a restart of the word. - Generous gaps. Make letter gaps clearly longer than element gaps, and word gaps longer still. Short gaps are the easiest way to garble a message.
Short messages work best: a name, a time, YES -.-- . ..., NO -. ---.
Learn the rhythm once, use it anywhere
Every one of these methods is easier when each letter is a rhythm you already know. If you learn on a Mac, Dot & Dash teaches the letters by keying them on a Morse machine you can press, with a tone and a paper tape on screen, and its Text to Morse turns a message into dots and dashes you can check before you tap it out. Once your hands know that K is long, short, long, it does not matter whether you key it, tap it or blink it.
Questions
Can you tap Morse code on a table?
Yes. A tap has no length, so use one tap for a dit and two quick taps for a dah, or two different sounds, such as a knuckle and a flat palm. Leave clearly longer pauses between letters, and longer still between words.
Is the tap code the same as Morse code?
No. The tap code counts knocks to pick a letter from a grid, while Morse uses short and long signals in a fixed pattern for each letter. A message in one cannot be read with the other.
How do you blink in Morse code?
Close both eyes quickly and firmly for a dit, keep them shut about three times as long for a dah, and keep them open for the gaps. Go slowly so that natural blinks are easy to ignore.
What did Jeremiah Denton blink in Morse?
In 1966, Jeremiah Denton, a US Navy pilot held as a prisoner of war, blinked T O R T U R E in Morse during a televised interview.