I used Serial.print to print these results in the Arduino serial monitor.
#AUDIO CLIPPING DETECTOR CODE#
All of this code takes place in the ADC interrupt (interrupts and runs each time a new analog in value is ready from A0, more info about what interrupts are and why we use them can be found here) prevData = newData //store previous value newData = ADCH //get value from A0 if (newData > prevData) timer++ //increment timer Then in the main loop() function, I calculated the frequency by dividing the timer rate by the period.
The important portion of the code is reproduced below. This way, the peaks are always located where the pulse wave toggles between its high and low states. For a simple sine wave, this will generate a pulse signal with the same frequency as the sine wave and a duty cycle of 50% (a square wave).
I wrote a detailed Instructable about that here.įirst I wanted to experiment with peak detection, so I wrote a piece of code (below) that outputs a high signal when the incoming audio signal has a positive slope, and outputs a low signal when the incoming audio signal has a negative slope. The first step of this project is to set up the audio input circuit. See my instructable about getting the Arduino to send and receive MIDI for lots of example code to get started audio effects- use the frequency information to reconstruct an audio signal from the tone() library or with some stored samples to make a cool effects box/synthesizer Pitch reactive projects- change the color of RGB LEDs with pitch, or make a lock that only opens when you sing a certain pitch or melody audio to MIDI conversion- get the Arduino to translate an incoming signal into a series of MIDI messages. Some project ideas for the code presented here include: I've also turned the LED attached to pin 13 into a clipping indicator, so you know if you need to adjust your signal's amplitude as you send it into the Arduino. The code uses a sampling rate of 38.5kHz and is generalized for arbitrary waveshapes. As a follow up to the Arduino Audio Input tutorial that I posted last week, I wrote a sketch which analyzes a signal coming into the Arduino's analog input and determines the frequency.
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