Called a crystal radio receiver, or sometimes a “cat’s whisker receiver,” this is an incredibly simple type of radio receiver that was popular in the earliest days of radio. The only power it requires to work is the received radio signal, which is used to produce sound. It is named after its most important component, the crystal detector or diode.
“AM radio was one of the first ways of transmitting audio to a very broad audience in the early 1900s, but it is still very popular today,” Hansen told Digital Trends. “It starts with the radio station converting their audio sound waves into electromagnetic waves, which can travel great distances. Each radio station uses a specific frequency that is constant, but the sound waves are mixed so they amplify and modulate the base radio wave. What makes the crystal radio so exciting is how simple the circuit is, and how it can be made out of normal household items. What I wanted to do was use my 3D modeling software to design a simple form that presents the components in such a straightforward way that it’s easy for the viewer to follow the circuit and understand how this is working. The radio waves received by the antenna pass through the coil of wire, which is acting as an inductor that determines the frequency. Then the diode will convert the receiving alternating current into direct current, which will vibrate the piezo speaker creating sound waves.”
Like a true gent, Hansen isn’t keeping the design to himself. “I always had the idea that this project was for the public,” he said. “I have uploaded the 3D files for people to download, as well as step-by-step instructions. I also recorded and edited an instructional video on YouTube with 3D animations to help people assemble, step by step. I hope that people will find this entertaining, educational — and have fun using this radio.”
Well, that’s your weekend busywork taken care of, then!