Electrolytic capacitor

Instant AC Power Filtering

Instant AC Power Filtering

You’ve been working hard at your Arduino-based servo project, and so far it’s working great. Time to untether it from your computer and let it run on its own, right? It works fine on USB power. It works fine on a 9-volt battery (while it lasts). You plug it into an adapter and…twitch…twitch…twitch. Suddenly it’s […]

Continue Reading
LED Sound Meter

LED Sound Meter

In this guide you will learn to created an array of LEDs that visually represent the volume picked up by an electret microphone. You will learn how to wire 3 different circuits which are the LED array (which is really many individual circuits), the microphone, and a button which can be used to change the display mode […]

Continue Reading
Micro FM Transmitter

Micro FM Transmitter

This circuit is commonly credited to Japanese multimedia artist Tetsuo Kogawa. It takes audio input through a 1/4″ phono jack and, constructed as shown, without the optional antenna connections, will broadcast an FM radio signal about 30 feet. This is the standard model of Mr. Kogawa’s simplest FM transmitter, which is slightly more complex than […]

Continue Reading