Bored you look out the window. The streets are empty, but you are not alone. Across the street, a figure appears behind another window. Just before you turn away a light catches your attention. It blinks in a pattern that doesn't look quite random, so you take your phone and search. After a quick search you find the Spread The Light initiative and download the app. You point your camera at the blinking and the message is decoded.

Stay strong, stay safe, we can do this!

The app informs you this light originated from Delft, Netherlands at 29-03-2020 16:42. On your screen a map shows that this message has been passed along 795 people and has traveled over 50 km. Amazing! A new button becomes available: "Forward this Light". You point your camera to the window, press the button and your flashlight blinks just like the figure across the street did. Nobody responds so you go back to Netflix.

A few hours later, your phone makes a noise it has never produced before. You check the notification and see someone in your proximity is emitting. You walk around the house and find that your back neighbour is transmitting a light. You decode it and next send the light you received earlier. Just like that you became a chain in the global network of light.

With your help we can spread the light faster than COVID-19 ever could!


Since communities have been quarantined at home we have seen everyone loves group projects. People have been applauding together and singing together. Using spread the light you can now communicate though flashing morse code!

Everyone with a phone can join: download the app, type your message and start sending. No people around? Enable location services and get notifications whenever someone in your proximity starts blinking. Then just look out the window, use the built-in camera to point at the blinking light and read what the other's have to say.

This project brings people together on with common goal: spreading light! It encourages people to get away from their couch, it gives people the opportunity to be part of something bigger and it is great fun to communicate through such on ancient system.

What we did

For most of us this was the first time doing app development. We started with a cross platform ionic app because we heard great stories about it. Even after 24 hours we weren't able to get the camera pixelstream to work so we decided to split up and try some other platforms. Two of us tried respectively native android and flutter while the others implemented the sending and receiving detection. Native android showed good camera stability so we implemented morse sending and morse receiving. At this moment, sending works perfectly but receiving is still a bit buggy. Since we spent so much time on the app development we didn't come around to location services and message tracking. You can find our beautiful code here.

Privacy Policy

Google Appstore requires a privacy policy, so here we go: all data received through the camera is used to detect a blinking light in the center of the screen. The only output of this process is the detected text. This includes no personal information. All images used to calculate this are immediately deleted. Nothing is stored. Nothing leaves the phone.

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