Bitcrusher

A straightforward fully stereo bitcrusher effect with extra controls for highpass and lowpass filtering. The amps provide a little make-up gain for the volume loss caused by the filters.

This sketch uses my modified Bitcrusher library LINK . The original bitcrusher object in the Teensy Audio Library would squeel quite painfully at lower bit-depths. My edit takes care of this.

Follow the link above for instructions on how to create the bitcrusher2 library. You need to do this before the sketch will run.

Ao = bit depth, A1 = sample rate, A2 = LPF and A3 = HPF. the footswitch and toggle do nothing in this sketch.

#define LED 3
#include <Bounce.h>

#include <effect_bitcrusher2.h>

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioInputI2S            i2s1;           //xy=368,395
AudioEffectBitcrusher2    bitcrusher2; //xy=527,449
AudioEffectBitcrusher2    bitcrusher1;    //xy=529,343
AudioFilterBiquad        biquad1;        //xy=690,342
AudioFilterBiquad        biquad2; //xy=694,451
AudioAmplifier           amp2; //xy=836,448
AudioAmplifier           amp1;           //xy=848,343
AudioOutputI2S           i2s2;           //xy=1003,397
AudioConnection          patchCord1(i2s1, 0, bitcrusher1, 0);
AudioConnection          patchCord2(i2s1, 1, bitcrusher2, 0);
AudioConnection          patchCord3(bitcrusher2, biquad2);
AudioConnection          patchCord4(bitcrusher1, biquad1);
AudioConnection          patchCord5(biquad1, amp1);
AudioConnection          patchCord6(biquad2, amp2);
AudioConnection          patchCord7(amp2, 0, i2s2, 1);
AudioConnection          patchCord8(amp1, 0, i2s2, 0);
AudioControlSGTL5000     sgtl5000_1;     //xy=871,578
// GUItool: end automatically generated code




Bounce footswitch = Bounce(0, 50);  // debounce the footswitch
Bounce D1 = Bounce(1, 50);          // debounce the toggle switch
Bounce D2 = Bounce(2, 50);          // "  "  "  "  "  "  "  "  "

// this section includes the function to check the toggle position
bool right;
bool middle;
bool left;
void checkToggle () {               // this is our function to check toggle position...
D1.update();  D2.update();          // check digital inputs connected to toggle (can delete I think)
if(digitalRead(1) && !digitalRead(2))   {right = 1; middle = 0; left = 0;}    // toggle is right
if(digitalRead(1) && digitalRead(2))  {right = 0; middle = 1; left = 0;}      // toggle is in the middle
if(!digitalRead(1) && digitalRead(2))   {right = 0; middle = 0; left = 1;}    // toggle is left
}

byte bitdepth = 16;                 // used to set bit depth
int samplerate = 44100;             // used to set sample rate
int lastsamplerate = 44100;         // used to set sample rate
int hpf;                            // used to set hpf cutoff frequency
int lpf;                            // used to set lpf cutoff frequency

void setup() {
 
  AudioMemory(40); // the "40" represents how much internal memory (in the Teensy, not the external RAM chip) is allotted for audio recording. It is measured in sample blocks, each providing 2.9ms of audio.
  sgtl5000_1.enable();    // this turns on the SGTL5000, which is the audio codec on the audio board
  sgtl5000_1.volume(1);   // this sets the output volume (it can be between 0 and 1)
  sgtl5000_1.inputSelect(AUDIO_INPUT_LINEIN); // selects the audio input, we always use Line In
  analogReadResolution(12); // configure the pots to give 12 bit readings
  pinMode(0, INPUT_PULLUP); // internal pull-up resistor for footswitch
  pinMode(1, INPUT_PULLUP); // internal pull-up resistor for toggle
  pinMode(2, INPUT_PULLUP); // internal pull-up resistor for toggle
  pinMode(3, OUTPUT);       // pin 3 (the LED) is an output;
  Serial.begin(9600);       // initiate the serial monitor. USB is always 12 Mbit/sec

  sgtl5000_1.audioPostProcessorEnable();
  
  analogReadAveraging(32);  

  // constant filters
  biquad1.setLowpass(0, 7000, 0.05);                  // set lpf
  biquad2.setLowpass(0, 7000, 0.05);                  // set lpf  

  // make-up gain
  amp1.gain(2);
  amp2.gain(2);
  
}

void loop() {
  
  // do bitcrushing
  bitdepth = (analogRead(A0) >> 8) + 1;             // bitdepth pot ranges from 1 to 16
  bitcrusher1.bits(bitdepth);                       // set bit depth
  bitcrusher2.bits(bitdepth);                       // set bit depth

  samplerate = (analogRead(A1) << 1) + 1000;        // samplerate pot ranges from 1000 to 9190
  bitcrusher1.sampleRate(samplerate);               // set sample rate
  bitcrusher2.sampleRate(samplerate);               // set sample rate
  

  // do filtering
  lpf = (analogRead(A2) << 1) + 1000;               // lpf pot ranges from 500 to 8240hz
  hpf = (analogRead(A3)  >> 2) + 120;               // hpf pot ranges form 20 to 4115
  biquad1.setLowpass(1, lpf, 0.7);                  // set lpf 
  biquad1.setHighpass(2, hpf, 0.5);                 // set hpf 
  biquad2.setLowpass(1, lpf, 0.7);                  // set lpf   
  biquad2.setHighpass(2, hpf, 0.5);                 // set hpf
}