So I wanted to test out the capabilities of some basic RF transmitter/receiver modules for the Arduino and, after going through this awesome tutorial, I decided to create a small project.
In this instructable, I am going to show you how to create a simple, wireless doorbell that plays a given melody. Why, you ask? Well, I noticed that, whenever someone (in that case parents) calls me for dinner, it is so quiet that I do not even notice that someone shouts my name. Since I do not check my phone so often, writing me a SMS does not do it either. I decided to stop that by creating an indoor doorbell, so whenever someone needs me downstairs, pressing a button is all that person has to do. The receiver will be placed in my room and play a really loud and annoying melody.
What you will need:Two Arduinos (I used the Arduino Nano with the ATmega 328 chip) Two project boxes Two 220 Ohm resistors Two LEDs One RF Transmitter (e.g. with 433 MHz) One RF Receiver (with a matching frequency) One button One vibration sensor (Piezo) - this can be replaced by another button if you do not have one One Piezo loudspeaker One/two switches (optional) Two 9V batteries or other power sources Wires Two PCB boards”

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