Arduino Air Cap-Sense Piano
If you are planning to make use of the buzzers lying around your home, then this article by Instructables will certainly help you. In this project, Instructables have made an air piano which is based upon cap-sense and the Arduino.The materials used for this project includes Aluminum tape or aluminum foil, some wires, 8 10M Ohm resistors, Piezo buzzer, Arduino and 9V battery or USB cable.
Before we proceed, it is important to understand that what exactly is a Cap-Sense and how does it work.The basic principle of the aluminum tape is to perceive the variance between human body capacitance and the capacitance of air. In technical words, the aluminum tape is encompassed with a small voltage by the Arduino which is responsible for creating an electrical field in that area. As soon as our finger as a conductor traces it or moves close to it, the electric field gets disturbed and a capacitor is formed.
This variation is noticed by the aluminum tape and it sends a signal to the Arduino with which we can tell it to send a signal to the buzzer.
So essentially, there are some square bits of aluminum tape, which are trapped onto a thick card while the card is fixed to a jumper cable and a resistor. Of this, eight replicas are made. All the other ends of the resistors are then attached together and also to the pin3 of the Arduino. Now the result will act as the common base pin for all the sensors.
We understand that the resistor values can be 2M or 10M or 40M Ohm. Each one of them have different purpose like 2M Ohm only senses when the aluminum tape is pressed upon. Similarly, 10M Ohm resistor senses hand at a little height of 2-4cm or so and 40M Ohm will sense rather a bit further.
As the aluminum tape pieces are held too close, everything becomes messy and then at that height intrusion occurs therefore other keys might get pressed. Therefore if you are planning to use 40M Ohm version, then please make sure to place the aluminum tape pieces a little far away from each other. Although, this project has used 10M Ohm for the device and it is working perfectly when the hands are waved over the note.
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