Now, I'm going to make a cymatics device combined with a speaker, audio amplifier and arduino due.
However the speaker makes a very loud noise even though the frequency is 1 ~ 70 Hz infrasonic.
Would you help me how to erase the noise?
/*
Simple Waveform generator with Arduino Due
* connect two push buttons to the digital pins 2 and 3
with a 10 kilohm pulldown resistor to choose the waveform
to send to the DAC0 and DAC1 channels
* connect a 10 kilohm potentiometer to A0 to control the
signal frequency
*/
#include "Waveforms.h"
#define oneHzSample 1000000/maxSamplesNum // sample for the 1Hz signal expressed in microseconds
volatile int wave1 = 0;
int i = 0;
int sample;
void setup() {
analogWriteResolution(12); // set the analog output resolution to 12 bit (4096 levels)
}
void loop() {
// Read the the potentiometer and map the value between the maximum and the minimum sample available
// 1 Hz is the minimum freq for the complete wave
// 170 Hz is the maximum freq for the complete wave. Measured considering the loop and the analogRead() time
sample = map(4000, 0, 4095, 0, oneHzSample);
sample = constrain(sample, 0, oneHzSample);
analogWrite(DAC1, waveformsTable[wave1][i]); // write the selected waveform on DAC1
i++;
if(i == maxSamplesNum) // Reset the counter to repeat the wave
i = 0;
delayMicroseconds(sample); // Hold the sample value for the sample time
}
// function hooked to the interrupt on digital pin 3
void wave1Select() {
wave1++;
if(wave1 == 4)
wave1 = 0;
}
Waveforms.h
#ifndef _Waveforms_h_
#define _Waveforms_h_
#define maxWaveform 4
#define maxSamplesNum 120
static int waveformsTable[maxWaveform][maxSamplesNum] = {
// Sin wave
{
0x7ff, 0x86a, 0x8d5, 0x93f, 0x9a9, 0xa11, 0xa78, 0xadd, 0xb40, 0xba1,
0xbff, 0xc5a, 0xcb2, 0xd08, 0xd59, 0xda7, 0xdf1, 0xe36, 0xe77, 0xeb4,
0xeec, 0xf1f, 0xf4d, 0xf77, 0xf9a, 0xfb9, 0xfd2, 0xfe5, 0xff3, 0xffc,
0xfff, 0xffc, 0xff3, 0xfe5, 0xfd2, 0xfb9, 0xf9a, 0xf77, 0xf4d, 0xf1f,
0xeec, 0xeb4, 0xe77, 0xe36, 0xdf1, 0xda7, 0xd59, 0xd08, 0xcb2, 0xc5a,
0xbff, 0xba1, 0xb40, 0xadd, 0xa78, 0xa11, 0x9a9, 0x93f, 0x8d5, 0x86a,
0x7ff, 0x794, 0x729, 0x6bf, 0x655, 0x5ed, 0x586, 0x521, 0x4be, 0x45d,
0x3ff, 0x3a4, 0x34c, 0x2f6, 0x2a5, 0x257, 0x20d, 0x1c8, 0x187, 0x14a,
0x112, 0xdf, 0xb1, 0x87, 0x64, 0x45, 0x2c, 0x19, 0xb, 0x2,
0x0, 0x2, 0xb, 0x19, 0x2c, 0x45, 0x64, 0x87, 0xb1, 0xdf,
0x112, 0x14a, 0x187, 0x1c8, 0x20d, 0x257, 0x2a5, 0x2f6, 0x34c, 0x3a4,
0x3ff, 0x45d, 0x4be, 0x521, 0x586, 0x5ed, 0x655, 0x6bf, 0x729, 0x794
}
,
};
#endif m
