Signalling Morse code with light
Before radio, ships talked to each other with signal lamps, and light is still a backup way to communicate at sea, in the mountains and in emergencies. The rhythm is the same as audio Morse: a dot is a short flash, a dash is three times longer, and the darkness between flashes separates symbols, letters and words.
Screen flash or phone flashlight
Screen flash turns your whole display white and black and works on any device. Phone flashlight uses your camera's torch, which is much brighter, on browsers that support it — mainly Chrome on Android. If it isn't supported, MorsePad tells you and flashes the screen instead.
Light timing and speed
Light Morse uses the same timing units as sound. At a given WPM, one dot lasts 1200 ÷ WPM milliseconds, so it is 60 ms at 20 WPM and 240 ms at 5 WPM. A dash is three dots long. The dark gap is one dot between the parts of a letter, three dots between letters and seven dots between words.
Eyes are slower than ears. Navy signal lamps are usually read at about 8–12 WPM, and beginners do best at 5–8 WPM. If the person watching keeps losing letters, lower the speed before you try anything else.
Tips for a readable signal
- Aim the light. Point the screen or the back of the phone directly at the person watching. A torch is easy to see across a dark field. A screen is best for short distances or indoor practice.
- Darkness helps. At night, a phone torch can be seen from far away. In daylight, the contrast drops sharply.
- Hold steady. Rest the phone on something solid so the flashes don't wobble out of view.
- Agree on a start. Send a few seconds of dark first, or begin with the call sign of the person you're signalling, so they know a message is coming.
Reading a light signal
Write each flash down as a dot or a dash as it comes, and leave gaps where the light stays off longer. Turn the marks into letters afterwards. You can paste what you wrote into the Morse code decoder to check it. To recognise letters faster, practise by ear with the Koch trainer, since the rhythm is the same.
The SOS signal
SOS is sent as one continuous pattern with no letter gaps: ...---... Press Send SOS and turn on Repeat to keep sending it. In a real emergency, call your local emergency number first. Light signals are a backup for when you can't call or be heard. Learn more patterns in the alphabet chart, or hear them with the audio generator.
Photosensitivity
Fast flashing can trigger seizures in people with photosensitive epilepsy. MorsePad shows a warning before any flashing starts. If your device is set to reduce motion, the warning mentions that too. Press Esc or tap the screen to stop at any time.