This blog article gathers a series of DIY radio experiments, ranging from early analog detection with Galena crystal receivers to digitally driven AM transmission via Arduino microcontrollers. Inspired by a love for vintage radio sets and low-power communication techniques, this collection explores both the simplicity of early unpowered detection and the elegance of amplitude modulation (AM) implemented in modern embedded systems. These are primarily short-range (QRP) experiments — ideal for educational settings, hobbyists, and radio tinkerers looking to bridge past and present technologies.

This cover design project began as a collaboration with the Italian author, screenwriter and director Alessandra Arcieri, for her cryptic futuristic novel Proiezione Origami. The book was published in 2015 by ilmiolibro self publishing and described as a romanzo cyberzen: a cyberpunk-leaning, dystopian story in which consciousness, code, combat, role-playing logic and spiritual circuitry blur into one unfolding stream.

“Rome, New York, Bombay. What will be the next target?”

Set in a fragmented future, the narrative moves through transcontinental power plays, high-stakes psycho-games and mythic figures recast inside digital landscapes. Its protagonist, Agent Alpha, must decode a layered conspiracy built by a corporate demiurge. Her mission is hidden inside Walt Whitman’s I Sing the Body Electric — not simply as a literary reference, but as a kind of hacked anthem for the electrified self.

A handcrafted direct injection box — a compact, AC-powered audio preamplifier designed for dynamic microphones, capable of cleanly converting mic-level signals to standard line-level output (-10dBV). Despite being AC powered, the small linear power supply has an optimal CMRR thanks to multiple filter stage after the rectifier bridge and the use of an inductance to reduce voltage fluctuations.

Features:

• Class A FET input stage with high linearity and extended bandwidth
• XLR input with adjustable gain
• Balanced or unbalanced line-level output
• Low noise, low distortion performance
• Wide frequency response

🎙️ Motivation & Design Approach

While trying to record audio using a Shure SM58 dynamic microphone directly into a Mac’s line-in jack, I encountered the usual issues: low gain, poor signal-to-noise ratio, and uninspiring tone. So, I decided to build my own solution — a clean, simple preamplifier with tone characteristics I personally enjoy.