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
Category: Metal Checker: The Electronic Switch
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
Parts List
Figure 11-1. The Metal Checker device
Introduction
An Electronic Tester Have you noticed household objects that appear to be made of metal when they’re not? You and a friend can build an instrument that checks the metal properties of household objects in your home using an Arduino and a few electronic parts. The Arduino Metal Checker emits a tone when a metal object… Continue reading Introduction