Morse code light translator
A Morse code light translator for your camera. Aim it at a flashing flashlight, lamp or LED, or open a video of one, and read the dots, dashes and text as they come. Free, and the video never leaves your device.
Your browser will ask to use the camera. Frames are measured here and never recorded. You can also drop a video on this card.
Last 10 secondslit stretches shaded
For a short message that can’t show its own speed. 2 to 30 WPM.
Decoded text
Put the flashing light inside the circle to begin…
Detected Morse
…
- Live camera or videoAim at a light, or open a saved clip
- Tap to aim the circleThe light needn’t sit in the middle
- Send by lightFlash a reply on the screen or flashlight
How to use
Press Start camera and aim at the flashing light, or press Choose a video (or drop one on the box) to read a light in a clip you saved. No light to hand? Press Try a sample.
Tap the preview where the light is, so it sits inside the circle. Hold the camera steady.
Watch the Brightness bar and the timeline: each flash should rise well above the red threshold line.
Letters missing or extra? Move Sensitivity, or tick Set the speed myself and enter the speed.
Copy the text or the Morse, press Open in translator to hear it, or open Send by light to flash a reply.
What it does
This Morse code light decoder turns flashes of light into dots, dashes and text:
Live camera. Front or back camera, with a camera picker and an exposure lock where the phone offers them.
Video files. An MP4, MOV or WebM clip plays once in the preview and is read frame by frame, for a light filmed earlier.
The circle goes to the light. Tap the preview or use the arrow keys, so the light needn’t sit in the middle of the picture.
Shows the signal. A brightness bar, a timeline of the last 10 seconds with the threshold, and the speed in words per minute.
Speed by hand. For a short message, such as TTT, that can’t show its own speed.
Send by light. The second tab flashes your message on the screen, the phone’s flashlight (not on iPhone) or a lamp on the page.
Keeps the result. Copy the text or the Morse, or open it in the translator to hear it, save it and share it.
Lights that work:
- A phone flashlight
- A desk lamp switched by hand
- A bike light
- The LEDs on radio gear
- A screen blinking white and black
- Sunlight flashed off a mirror (lower the sensitivity)
Any light that goes fully on and off and stands out from the room around it.
How it works
The same decoder as the microphone, fed with brightness instead of sound, frame by frame:
Watches every frame
In each frame it measures the brightest quarter of the pixels inside the circle, so even a small lamp far away makes a clear change against the room.
Finds lit and dark
Frames are timed by the video itself and evened out onto a steady 10 millisecond grid.
The threshold sets itself between the dark and lit levels of the 1.5 seconds before each moment and the 0.4 seconds after.
Reads the flashes
Long and short flashes give dashes and dots; short and long dark gaps split letters and words, by the 1, 3 and 7 units of ITU-R M.1677-1.
The speed is learned from all the flashes so far, and a long pause starts a new transmission.
A phone camera films about 30 frames a second, so a short flash is seen in only two or three frames. It reads reliably at about 15 WPM or slower, where a dot lasts 80 milliseconds. Cameras that film 60 frames a second read faster.
Examples
Test videos of a lamp, made frame by frame, and what the translator reads:
| Video | It reads |
|---|---|
| SOS at 12 WPM, a lamp in a dark room | SOS · about 12 WPM |
| HELLO WORLD at 12 WPM | HELLO WORLD |
| PARIS PARIS at 5 WPM | PARIS PARIS · 5 WPM |
| PARIS PARIS at 20 WPM, 30 frames a second | PARIS PARIS · about 20 WPM |
| PARIS PARIS at 22 WPM, 30 frames a second | Nothing: too fast for 30 frames a second |
| PARIS PARIS at 35 WPM, 60 frames a second | PARIS PARIS · about 34 WPM |
| SOS with the lamp near the top-left corner | Nothing with the circle in the middle; SOS once the circle is moved onto the lamp |
| SOS from a faint lamp, lit only a little brighter than dark | Nothing at Sensitivity 50%; SOS at 100% |
| TTT at 10 WPM | S: three flashes of one length could be dots. With the speed set to 10, TTT |
Good questions
Frequently asked questions.
About the Morse code light translator
How do I translate a flashing light into Morse code?
Press Start camera, aim at the light and tap the preview where it is, so it sits in the circle. Each flash is timed: short ones are dots, long ones dashes, and the dark gaps split letters and words. The text appears as the light flashes, with the speed in words per minute.
How do you read Morse code from a light by eye?
Compare the flashes: a dash lasts three times as long as a dot. A short dark gap is inside a letter, a gap three times longer ends the letter, and one seven times longer ends the word. Write the dots and dashes down and look them up in the Morse code alphabet, or tap them on the Morse keyboard.
Can it decode a flashing light in a video?
Yes. Press Choose a video and pick an MP4, MOV or WebM file: it plays once in the preview and is read frame by frame. Tap where the light is first.
For a video you can only stream, play it full screen on another device and point the camera at it. If the Morse in a video is a beep, use the audio translator.
How fast and how far can it read?
Most phone cameras film 30 frames a second, which reads light sent at about 15 WPM or slower; in our tests a clean lamp read at 20 WPM at 30 frames a second, and at 35 WPM at 60. Distance matters less than contrast: a light far away works if it is the brightest thing in the circle and the camera is steady.
Is there an app that translates Morse code light?
No install is needed: this page works in the browser on Android phones, iPhones, tablets and laptops with a camera. Allow the camera when asked. The video is read on your device and never uploaded.
How do you signal SOS with a flashlight?
Flash three short, three long and three short (...---...) as one run, with no gaps between the letters. Open Send by light, tap SOS and press Flash the screen, or Use the flashlight on an Android phone.
The Flashlight signaler has more on flashlights and lamps. In a real emergency, call your local emergency number first.
Can I send Morse code by light here too?
Yes. The Send by light tab turns a message into flashes on the screen, the phone’s flashlight (iPhones don’t let web pages use it) or a lamp on the page, at 3 to 15 WPM. Screen flashes stay at 7 WPM or slower and come after a warning for people sensitive to flashing light.
Trust and limits
Private by design.
Honest about limits.
On your device
Measured on your device
Camera frames and video files are measured on your device, on a small copy of each frame 96 pixels wide, and are never uploaded or recorded.Know the limits
One steady light
It reads one light at a time, inside the circle, and needs the light to switch fully on and off. A light that only dims, a flickering tube, or a camera that keeps changing its exposure can add or lose letters; lock the exposure where the phone offers it.
The frame rate limits the speed to about 15 WPM at 30 frames a second. Very uneven hand sending may lose letters.
Know the limits
Flashing light warning
Flashing light can affect people with photosensitive epilepsy: the Send by light tab keeps screen flashes slow and warns first, and the sample lamp flashes at 7 WPM, with its picture hidden if your device asks for reduced motion.ITU-R M.1677-1
Timing standard
Timing follows ITU-R M.1677-1. Maintained by Translate Morse Code, an independent site; last updated October 2026.