Summary of Pitch follower using the tone() function using Arduino
This project demonstrates how to use Arduino's tone() function to generate a pitch that varies with an analog input from a photoresistor. A speaker connected to a digital pin outputs sound with frequency mapped to the light level detected by the photoresistor. The analog input range is mapped to a frequency range audible to humans, typically between 120 Hz and 1500 Hz. The circuit includes a photoresistor powered by 5V and connected through a 4.7K resistor to ground, and the speaker is connected through a 100-ohm resistor.
Parts used in the Pitch follower:
- 8-ohm speaker
- Photoresistor (photocell)
- 4.7K ohm resistor
- 100 ohm resistor
- Breadboard
- Hook up wire
This example shows how to use the tone() command to generate a pitch that follows the values of an analog input
Circuit
image developed using Fritzing. For more circuit examples, see the Fritzing project page
Connect one terminal of your speaker to digital pin 9 through a 100 ohm resistor, and its other terminal to ground. Power your photoresistor with 5V, and connect it to analog 0 with the addition of a 4.7K resistor to ground.
Schematic
Code
The code for this example is very simple. Just take an analog input and map its values to a range of audible pitches. Humans can hear from 20 – 20,000Hz, but 120 – 1500 usually works pretty well for this sketch.
You’ll need to get the actual range of your analog input for the mapping. In the circuit shown, the analog input value ranged from about 400 to about 1000. Change the values in the map() command to match the range for your sensor.
The sketch is as follows:
Pitch follower
Plays a pitch that changes based on a changing analog input
circuit:
* 8-ohm speaker on digital pin 8
* photoresistor on analog 0 to 5V
* 4.7K resistor on analog 0 to ground
created 21 Jan 2010
modified 31 May 2012
by Tom Igoe, with suggestion from Michael Flynn
This example code is in the public domain.
http://arduino.cc/en/Tutorial/Tone2
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Hardware Required
- 8-ohm speaker
- 1 photocell
- 4.7K ohm resistor
- 100 ohm resistor
- breadboard
- hook up wire
