Bakelite to the Future - 1950s rotary phone ESP32 bluetooth headset

Edit: since creating this post I've also created a video about this project on YouTube. See it below or jump straight into all the details below. Here's a very beautiful antique rotary phone. It's a Dutch PTT phone model called simply "1950" . But, what's this at the back? A USB-C port? A peek inside shows us some weird things! How did that LiPO battery get there? Ok let's quit the jokey intro,…