Christmas message

To decode the message, follow these steps:

  1. If you don’t have phyphox installed, explore to learn what it is. Then follow the download buttons to install it on your phone.
  2. Visit this page on your phone.
  3. On your phone: Click this link to open the decoder in phyphox. Start the experiment.
  4. On your PC or any other device: Play the video, so the phone can hear it and watch the result on your phone. On slower phones it may take longer to see a nice results.

How does this work?

Each tone you hear is actually four tones of different frequencies at the same time. Phyphox analyses these tones to extract these frequencies (for those mathematically inclined: it is done using a Fourier transform) and draws a point at a position given by two of these four frequencies. The third frequency yields the color and a number of repeated points and the fourth frequency is a checksum to reduce the number of falsely recognized points. Eventually, all those points form up an image.

Create your own message

You can create your own message using the generator. Just drag your image into the editor and download the audio file. Small images with strong thick lines work best.

Old version

We initially already tried this idea in 2021. If you want to try the old version, you can still access the video, the receiver part for the app and the generator.