The project called "Wonderfoon" was initially created by Leo Willems and many people made their own improvements on that design. Although I wasn't aware of that when I started working on my implementation (which could have saved me a lot of work), but fortunately it resulted in a new project which I call the TeleJukebox.
Why this project?
It all started when my wife saw a news item https://nos.nl/video/2299835-de-wonderfoon-voor-dementerende-ouderen.html
This small item was about a rotary phone project that seemed to be focused on people who have Alzheimer. Now Because I'm a technician who has a wife that works with elderly people, she asked me if I could build such a phone. She also provided me with a link to this website: http://www.wonderfoon.nl
That website had instructions about how you could make such a phone. Which sounded great from my wife's perspective, but when I started to read those instructions, I quickly realized that I would not be following them. Basically because although I love the project, it really hurts my technical heart to see that it required these perfectly fine working phones to be dismantled, ruined, destroyed. It shouldn't be required to make this wonder of 1965 technology (which today we see as just "a simple phone") to be badly damaged only to make it perform the simple task of playing music. And then there was also the complexity (or to be more precise the technical overkill) of the design in combination with the demolition work required to assemble it... I wouldn't say that I was shocked, but it certainly didn't make me happy either.
So after a few minutes of processing this information I began to wonder, couldn't this be more simple, more cheaply, just a simple PCB in a small case where you plug the phone in. A simpler design could result in more of these devices being made and therefore more joy among the elderly could be achieved. Also... many innocent phones could be saved from permanently being crippled beyond repair. Although at that moment I was only interested in making only one (because that's all my wife asked me) but it never hurts to think ahead. Because if I make one, she might ask me someday to make another one...
So I made a new design based on parts I had lying around and that are still easily obtainable, build it on a piece of experimenters PCB and named it TeleJukebox. I chose that name to prevent confusion with the existing Wonderfoon. And then I put it all on github (see download link below).
A few weeks later I was contacted by someone from a maker space asking me if I had a PCB design for it. Now I didn't make a PCB since I used experimenters PCB, so he made a PCB design based upon my schematics himself. The person who contacted me was Paul, an editor for the website Tweakers. After his experiments with my design he was so pleased with this simplified concept that he decided to make an article around it and publishing it in the Tweakers magazine and website Tweakers
Now the funny thing is, that if I knew that my design was getting so much attention, I might have thought a little bit longer about some of the design choices I had to make. Perhaps it was better that I didn't knew that at the time, as this might have prevented me from making it way too complicated.
All the information I have on this project is stored on my github page: https://github.com/JanDerogee/TeleJukebox
If you have any questions just send me an email, but make sure that you've read the user manual first.