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The reverb effect simulates the sound that results from reflections from surrounding walls. Making the impression that you are playing in a large room. To simulate it most digital reverbs produce two parts: the early Reflections and the reverb component, which are just the signal delayed with different timings.
In this code 3 delay buffers are used to mimic the effect of the reflexion on different walls: This is the complete code: // CC-by-NC-www.Electrosmash.com/rights
// pedalshield_mega_reverb.ino uses 3 Delay Buffers to mimic the reflexion from 3 walls/
// pressing the pushbutton_1 or 2 makes the reverb longer or shorter, changing the "distance" of the walls
#include "U8glib.h"
U8GLIB_SH1106_128X64 u8g(U8G_I2C_OPT_NO_ACK); // Display which does not send ACK
//defining harware resources.
#define LED 13
#define FOOTSWITCH 12
#define TOGGLE 2
#define PUSHBUTTON_1 A5
#define PUSHBUTTON_2 A4
//defining the output PWM parameters
#define PWM_FREQ 0x00FF // pwm frequency - 31.3KHz
#define PWM_MODE 0 // Fast (1) or Phase Correct (0)
#define PWM_QTY 2 // 2 PWMs in parallel
//other variables
int input, vol_variable=512;
int counter=0;
unsigned int ADC_low, ADC_high;
#define MAX_DELAY1 3100
#define MAX_DELAY2 400
#define MAX_DELAY3 75
unsigned int DelayBuffer1[MAX_DELAY1];
unsigned int DelayBuffer2[MAX_DELAY2];
unsigned int DelayBuffer3[MAX_DELAY3];
unsigned int DelayCounter1 = 0;
unsigned int DelayCounter2 = 0;
unsigned int DelayCounter3 = 0;
unsigned int Delay_Depth1 = MAX_DELAY1;
unsigned int Delay_Depth2 = MAX_DELAY2;
unsigned int Delay_Depth3 = MAX_DELAY3;
void setup() {
//setup IO
pinMode(FOOTSWITCH, INPUT_PULLUP);
pinMode(TOGGLE, INPUT_PULLUP);
pinMode(PUSHBUTTON_1, INPUT_PULLUP);
pinMode(PUSHBUTTON_2, INPUT_PULLUP);
pinMode(LED, OUTPUT);
pinMode(6, OUTPUT); //PWM0 as output
pinMode(7, OUTPUT); //PWM1 as output
// setup ADC
ADMUX = 0x60; // left adjust, adc0, internal vcc
ADCSRA = 0xe5; // turn on adc, ck/32, auto trigger
ADCSRB = 0x00; // free running mode
DIDR0 = 0x01; // turn off digital inputs for adc0
// setup PWM
TCCR4A = (((PWM_QTY - 1) << 5) | 0x80 | (PWM_MODE << 1)); //
TCCR4B = ((PWM_MODE << 3) | 0x11); // ck/1
TIMSK4 = 0x20; // interrupt on capture interrupt
ICR4H = (PWM_FREQ >> 8);
ICR4L = (PWM_FREQ & 0xff);
DDRB |= ((PWM_QTY << 1) | 0x02); // turn on outputs
sei(); // turn on interrupts - not really necessary with arduino
}
void loop()
{
//Turn on the LED if the effect is ON.
if (digitalRead(FOOTSWITCH)) digitalWrite(LED, HIGH);
else digitalWrite(LED, LOW);
//write the OLED while waiting for the Timer 4 interruption.
u8g.firstPage();
do {
u8g.setFont(u8g_font_helvR14r);
u8g.drawStr( 0, 14, " REVERB ");
u8g.drawStr( 0, 32, "ECHO 1: ");
u8g.setPrintPos(80, 32);
u8g.print(Delay_Depth1);
u8g.drawStr( 0, 48, "ECHO 2: ");
u8g.setPrintPos(80, 48);
u8g.print(Delay_Depth2);
u8g.drawStr( 0, 64, "ECHO 3: ");
u8g.setPrintPos(80, 64);
u8g.print(Delay_Depth3);
} while( u8g.nextPage() );
}
ISR(TIMER4_CAPT_vect)
{
// get ADC data
ADC_low = ADCL; // ADC_low always 0 to save space
ADC_high = ADCH;
//store the high bit only for
DelayBuffer1[DelayCounter1] = ((((ADC_high << 8) | ADC_low) + 0x8000)+DelayBuffer1[DelayCounter1])>>1;
DelayBuffer2[DelayCounter2] = ((((ADC_high << 8) | ADC_low) + 0x8000)+DelayBuffer1[DelayCounter2])>>1;
DelayBuffer3[DelayCounter3] = ((((ADC_high << 8) | ADC_low) + 0x80000)+DelayBuffer1[DelayCounter3])>>1;
counter++; //to save resources, the pushbuttons are checked every 100 times.
if(counter==100)
{
counter=0;
if (!digitalRead(PUSHBUTTON_1)) {
if (Delay_Depth1<MAX_DELAY1)Delay_Depth1=Delay_Depth1+1;
if (Delay_Depth2<MAX_DELAY2)Delay_Depth2=Delay_Depth2+1;
if (Delay_Depth3<MAX_DELAY3)Delay_Depth3=Delay_Depth3+1;
digitalWrite(LED, LOW); //blinks the led
}
if (!digitalRead(PUSHBUTTON_2)) {
if (Delay_Depth1>0)Delay_Depth1=Delay_Depth1-1;
if (Delay_Depth2>0)Delay_Depth2=Delay_Depth2-1;
if (Delay_Depth3>0)Delay_Depth3=Delay_Depth3-1;
digitalWrite(LED, LOW); //blinks the led
}
}
//Increse/reset delay counter.
DelayCounter1++;
if(DelayCounter1 >= Delay_Depth1) DelayCounter1 = 0;
DelayCounter2++;
if(DelayCounter2 >= Delay_Depth2) DelayCounter2 = 0;
DelayCounter3++;
if(DelayCounter3 >= Delay_Depth3) DelayCounter3 = 0;
//the output signal is = delayed signal + current signal.
input = (DelayBuffer1[DelayCounter1]+DelayBuffer2[DelayCounter2]+DelayBuffer3[DelayCounter3]+(((ADC_high << 8) | ADC_low) + 0x8000))>>2;
//write the PWM signal
OCR4AL = ((input + 0x8000) >> 8); // convert to unsigned, send out high byte
OCR4BL = input; // send out low byte
} |
Last Edit: 4 years 5 months ago by ElectroSmash_Team.
The administrator has disabled public write access.
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Long Reverb:
This approach is exactly the same as followed to do the delay and long_delay codes, which is to use only 8 bits instead of 16 to save the data, you can see how the buffers are 8 bits: byte DelayBuffer3[MAX_DELAY]; unsigned int DelayBuffer3[MAX_DELAY]; Some other operations are needed to adjust the operations to 8 bits, but you can see that they are just a few lines. This effect is noisier than the 16 bits Reverb, but it is a good exercise to learn how to use the resources: This is the complete code of the long_reverb: // CC-by-NC-www.Electrosmash.com/rights
// pedalshield_mega_reverb.ino uses 3 Delay Buffers to mimic the reflexion from 3 walls/
// pressing the pushbutton_1 or 2 makes the reverb longer or shorter, changing the "distance" of the walls
#include "U8glib.h"
U8GLIB_SH1106_128X64 u8g(U8G_I2C_OPT_NO_ACK); // Display which does not send ACK
//defining harware resources.
#define LED 13
#define FOOTSWITCH 12
#define TOGGLE 2
#define PUSHBUTTON_1 A5
#define PUSHBUTTON_2 A4
//defining the output PWM parameters
#define PWM_FREQ 0x00FF // pwm frequency - 31.3KHz
#define PWM_MODE 0 // Fast (1) or Phase Correct (0)
#define PWM_QTY 2 // 2 PWMs in parallel
//other variables
int input, vol_variable=512;
int counter=0;
unsigned int ADC_low, ADC_high;
#define MAX_DELAY1 6100
#define MAX_DELAY2 1100
#define MAX_DELAY3 555
byte DelayBuffer1[MAX_DELAY1];
byte DelayBuffer2[MAX_DELAY2];
byte DelayBuffer3[MAX_DELAY3];
unsigned int DelayCounter1 = 0;
unsigned int DelayCounter2 = 0;
unsigned int DelayCounter3 = 0;
unsigned int Delay_Depth1 = MAX_DELAY1;
unsigned int Delay_Depth2 = MAX_DELAY2;
unsigned int Delay_Depth3 = MAX_DELAY3;
void setup() {
//setup IO
pinMode(FOOTSWITCH, INPUT_PULLUP);
pinMode(TOGGLE, INPUT_PULLUP);
pinMode(PUSHBUTTON_1, INPUT_PULLUP);
pinMode(PUSHBUTTON_2, INPUT_PULLUP);
pinMode(LED, OUTPUT);
pinMode(6, OUTPUT); //PWM0 as output
pinMode(7, OUTPUT); //PWM1 as output
// setup ADC
ADMUX = 0x60; // left adjust, adc0, internal vcc
ADCSRA = 0xe5; // turn on adc, ck/32, auto trigger
ADCSRB = 0x00; // free running mode
DIDR0 = 0x01; // turn off digital inputs for adc0
// setup PWM
TCCR4A = (((PWM_QTY - 1) << 5) | 0x80 | (PWM_MODE << 1)); //
TCCR4B = ((PWM_MODE << 3) | 0x11); // ck/1
TIMSK4 = 0x20; // interrupt on capture interrupt
ICR4H = (PWM_FREQ >> 8);
ICR4L = (PWM_FREQ & 0xff);
DDRB |= ((PWM_QTY << 1) | 0x02); // turn on outputs
sei(); // turn on interrupts - not really necessary with arduino
}
void loop()
{
//Turn on the LED if the effect is ON.
if (digitalRead(FOOTSWITCH)) digitalWrite(LED, HIGH);
else digitalWrite(LED, LOW);
//write the OLED while waiting for the Timer 4 interruption.
u8g.firstPage();
do {
u8g.setFont(u8g_font_helvR14r);
u8g.drawStr( 0, 14, "LONGREVERB");
u8g.drawStr( 0, 32, "ECHO 1: ");
u8g.setPrintPos(80, 32);
u8g.print(Delay_Depth1);
u8g.drawStr( 0, 48, "ECHO 2: ");
u8g.setPrintPos(80, 48);
u8g.print(Delay_Depth2);
u8g.drawStr( 0, 64, "ECHO 3: ");
u8g.setPrintPos(80, 64);
u8g.print(Delay_Depth3);
} while( u8g.nextPage() );
}
ISR(TIMER4_CAPT_vect)
{
// get ADC data
ADC_low = ADCL; // ADC_low always 0 to save space
ADC_high = ADCH;
//store the high bit only for
DelayBuffer1[DelayCounter1] = (ADC_high+DelayBuffer1[DelayCounter1])>>1;
DelayBuffer2[DelayCounter2] = (ADC_high+DelayBuffer1[DelayCounter2])>>1;
DelayBuffer3[DelayCounter3] = (ADC_high+DelayBuffer1[DelayCounter3])>>1;
counter++; //to save resources, the pushbuttons are checked every 100 times.
if(counter==100)
{
counter=0;
if (!digitalRead(PUSHBUTTON_1)) {
if (Delay_Depth1<MAX_DELAY1)Delay_Depth1=Delay_Depth1+1;
if (Delay_Depth2<MAX_DELAY2)Delay_Depth2=Delay_Depth2+1;
if (Delay_Depth3<MAX_DELAY3)Delay_Depth3=Delay_Depth3+1;
digitalWrite(LED, LOW); //blinks the led
}
if (!digitalRead(PUSHBUTTON_2)) {
if (Delay_Depth1>0)Delay_Depth1=Delay_Depth1-1;
if (Delay_Depth2>0)Delay_Depth2=Delay_Depth2-1;
if (Delay_Depth3>0)Delay_Depth3=Delay_Depth3-1;
digitalWrite(LED, LOW); //blinks the led
}
}
//Increse/reset delay counter.
DelayCounter1++;
if(DelayCounter1 >= Delay_Depth1) DelayCounter1 = 0;
DelayCounter2++;
if(DelayCounter2 >= Delay_Depth2) DelayCounter2 = 0;
DelayCounter3++;
if(DelayCounter3 >= Delay_Depth3) DelayCounter3 = 0;
//the output signal is = delayed signal + current signal.
input = (DelayBuffer1[DelayCounter1]+DelayBuffer2[DelayCounter2]+DelayBuffer3[DelayCounter3]+ADC_high)>>2;
//write the PWM signal
OCR4AL = input ; // convert to unsigned, send out high byte
// OCR4BL = input; // send out low byte
} |
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