Xaver Schrems

Yes you can only play one note at a time. But for me thats one of the key things about the stylophone - it's simplicity and remarkable sound that is generated (by the vibrato effect) by swiping over the keypad! And I wanted to keep it easy for everyone to make in a few hours. Thats why I made it the way it is. But I'd be also excited to see your version with the sperate ne555s! I'd be interested how it sounds like and behaves. But one major disadvantage is if you want to keep it portable (what was important to me) you would need to make it with smd components (what may not be easy for everyone). Nevertheless I'm looking forward to see your version of the stylophone!

I'm sorry i answered so late! But great to hear that you succesfully made it!

First of all thank you for your feedback! I now expanded step 4 and went a bit more into detail. Additionally I included a pdf version of the schematic so you can zoom in it and e.g. be able to see how the speaker is wired up.