Stokos 4 is a random based electronic synthesiser made by Lluís Callejo in the early 1970’s

This site is about this machine and its virtual version developed by Albert Callejo in 2013.

This is a personal project created to pay tribute to the original project and to keep it alive. For the moment,  just as an approximation/simulation.

I developed it using Android Studio,  Processing 2 (graphical Java-based library),  PureData as sound engine LibPD to embed PD on the app.  

and 3D software to create 3D Model and generate the user interface


Read the manual on the help section in the app, to understand what you’re doing there,  or visit this page: Manual


As the Ui is pretty dense, is recommended to use an Android Tablet to play it commodily, and, as the sound that it produces is totally randomly generated, so, please, be patient and don’t wait for ‘musical’ or melodic sounds, so, tell your brain to take his time to accomodate to this other kind of music… however, if you get tricky on it, you can achieve some textures, or different kinds of fun abstract sounds.


Use the Mute buttons to toggle the voices, so, is difficult to resist more than one minute the 4 voices on at same time!!


The project is thoght to be collaborative and Open Source, so ( in a short time ) I’ll upload the code and ui assets on GitHub for who will to improove it or to just create another skin.

If you are really interested, so, please contact me to explain your ideas, I’ll receive it gratefully, due my coding and pureData knowing limitations, some collaboration to make it better is always welcome.



This project is under CC BY license, so, if you are music producer, and create some track with help of Stokos4 app, I will agree to be advised and to publish something like “created with Stokos4 app” or just a link to it..


I agree to Museu de la Música de BarcelonaPhonos and Telenoika Audiovisual community  for their support to me to create this project in the beginning.