Month: November 2022

Introduction

Resistors are color coded to indicate their resistive value. If you already know how to read the color code—or once you learn how—you’ll be able to glance at a resistor and tell automatically what its value is. But what about other components in your projects? What about the LEDs, potentiometers, buzzers, or even the wires… Continue reading Introduction

Circuit Theory

The 2N3904 or S39013 NPN transistor amplifies or increases the audio signal created by the Arduino. The transistor has an amplification value called “gain” used to determine the volume of an electrical signal. A typical gain value engineers use in designing simple amplifiers like this one is 100. The mini 8Ω speaker can be wired… Continue reading Circuit Theory

Upload the Theremin Sketch

It’s time to upload the sketch to the Arduino with the Theremin’s photocell and simple transistor amplifier circuits built on the MakerShield. Example 12-1 operates the Arduino-based Theremin using a photocell and a simple transistor amplifier circuit. Here are the steps you’ll need to follow: Once the Theremin sketch has been uploaded to the Arduino, the mini 8Ω… Continue reading Upload the Theremin Sketch

Let’s Build a Theremin

The Theremin, invented in 1920 by Russian inventor Leon Theremin, uses an electronic circuit called an oscillator to create different sounds. In our Theremin, we’re using the Arduino as an oscillator by programming it to select different tones based on changing light levels. The tone changes are made by waving your hand over a photocell, creating various… Continue reading Let’s Build a Theremin

Introduction

A Simple Transistor Amplifier Electronic circuits that produce audible sounds have been used to create strange and eerie audio effects for science-fiction movies like Star Wars and Marvel’s The Avengers. The Theremin is a device that generates different electronic sounds by waving hands over and around a pair of protruding antennas. You can make your own awesome Theremin using… Continue reading Introduction

Circuit Theory

The 2N3904 NPN transistor provides a signal to the Arduino, allowing it to turn on the piezo buzzer. Placing a metal object on the test probes allows electrical current to flow through the transistor, turning it on like a pushbutton switch. The 1KΩ (kilo-ohm) resistor provides a control voltage (+5VDC) to the Arduino, allowing it… Continue reading Circuit Theory

Upload the Metal Checker Sketch

With the Metal Checker circuit built on the MakerShield, it’s time to upload the sketch. Example 11-1 operates the piezo buzzer using a small transistor. Here are the steps you’ll need to follow: The Arduino will turn on the piezo buzzer. Now you’re ready to unlock the metal mysteries hiding in your house! Example 11-1. The Metal Checker sketch THE… Continue reading Upload the Metal Checker Sketch

Let’s Build a Metal Checker

The Metal Checker is a cool electronics device to build with an Arduino and some easy-to-obtain electronic parts. You can build the electronic circuit on an ordinary breadboard or the MakerShield. Building the Metal Checker on the MakerShield allows the device to fit nicely inside a Maker’s toolbox or workbench drawers. Also, the MakerShield is… Continue reading Let’s Build a Metal Checker