DIY Sound Laser : Big Speakers Aren’t Required for Pinpoint Sound

Create a focused speaker so your music targets only the listener. That demodulates at 40 kilohertz, with an H-bridge and ...
Hackaday

DIY laser

While some decent lasers are out there for under $400 USD, they tend to be a little small. What if you wanted something a little nicer but didn’t want to jump to the $2,000 category? The answer for ...