I made a crystal radio when I was a kid about 11 or 12 years old, I think. Crystal radios don’t have a power supply. They get enough energy from the electromagnetic radio waves to produce sound in headphones. But they need a strong signal and a good antenna to get enough energy. I mounted one of my crystal radios on my bike, thinking I could ride about town and listen. I was disappointed because a moving bike couldn’t have a good enough antenna. I could hear a station if I rode my bike to the transmitter and parked about 100 yards from the transmitting antenna.
That interest in crystal radios got me started in electronics and I dreamed of becoming a “ham” with my own FCC license. But my interest shifted to audio and high-fidelity. I never was a musician but I enjoy listening. It became my goal to someday have the world’s best audio playback system. I got sidetracked on that goal because I soon had to buy refrigerators, washing machines, and such.
Even though I had to buy household things, I managed to have a decent audio system. However, my enjoyment of music got a serious setback when I experienced sudden hearing loss. It was not only music, but normal conversation was seriously impaired. After I got over the shock of sudden hearing loss, which took several years, I learned there were some things that worked with hearing aids that would be of benefit to me. These things were very simple amplifiers, microphones, wireless devices, etc. We nowadays call those kind of things Assistive Listening Devices, or ALD for short. The ALD industry has matured and now there are very sophisticated devices available. It is now my goal to design really simple things that are useful. So that is what this blog will be about – simple devices that other hobbyists can make or maybe improve upon.