Phil, a high school chemistry teacher and YouTube creator, noticed that a small solar panel emitted a faint sound when connected to a speaker and exposed to light. From this, he deduced that he could transmit sound wirelessly using light, with the solar panel acting as a receiver. So, he decided to build a wireless transmitter using his iPad, a solar panel, and a cheap speaker, and shared the short build on his YouTube channel.
The first thing he did was to build an amplifier to strengthen the audio…