Hi,
I have posted my questions for several times. Until now my question doesn't solve:
I am working on a peizo sensor project. for a Peizo sensor, it will generate a voltage when a force is applied on its surface.
The arduino Pin A0 samples the voltage across the sensor. I hope the arduino Pin 6 will generate a sinewave to drive the sensor to vibrate when I press the sensor. I use a relay to control the circuit.
Now the question is :
1.when I make my code generate sinewave, it can drive the sensor to vibration.
2.When I make my code only judge the press, it seems to work (the flag "PressStatus" can set high when I press the sensor).
3.when I set a threshold: I wanna call the sinewave generation function (ISR) when I press the sensor. But the code cannot trigger the threshold and the sinewave doesn't drive the sensor.
The question have annoyed my for a long time. Pls guys help me out. Thank you so much. My code has something wrong?
my code is:
#include <stdint.h>
#include <avr/interrupt.h>
#include <avr/io.h>
#include <avr/pgmspace.h>
#define SAMPLE_RATE 8000/0.64 //control the frequency of the output signal =16M/SAMPLE_RATE/256
int outputPin = 6; // (PCINT22/OC0A/AIN0)PD6, Arduino Digital Pin 6
volatile uint16_t sample;
const int sinewave_length=256;
int led =13;
const int N=5;
float voltageValue[N];
float voltage[N];
volatile int PressStatus;//Pressing flag;
const unsigned char sinewave_data[] PROGMEM = {
0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,
0xb0,0xb3,0xb6,0xb9,0xbc,0xbf,0xc1,0xc4,0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd5,0xd8,
0xda,0xdc,0xde,0xe0,0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf5,
0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfe,0xfd,0xfc,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,
0xf6,0xf5,0xf3,0xf2,0xf0,0xef,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe2,0xe0,0xde,0xdc,
0xda,0xd8,0xd5,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0xc1,0xbf,0xbc,0xb9,0xb6,0xb3,
0xb0,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x98,0x95,0x92,0x8f,0x8c,0x89,0x86,0x83,
0x80,0x7c,0x79,0x76,0x73,0x70,0x6d,0x6a,0x67,0x63,0x60,0x5d,0x5a,0x57,0x54,0x51,
0x4f,0x4c,0x49,0x46,0x43,0x40,0x3e,0x3b,0x38,0x36,0x33,0x31,0x2e,0x2c,0x2a,0x27,
0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0x17,0x15,0x13,0x12,0x10,0x0f,0x0d,0x0c,0x0a,
0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x03,0x02,0x01,0x01,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x05,0x06,0x07,0x08,
0x09,0x0a,0x0c,0x0d,0x0f,0x10,0x12,0x13,0x15,0x17,0x19,0x1b,0x1d,0x1f,0x21,0x23,
0x25,0x27,0x2a,0x2c,0x2e,0x31,0x33,0x36,0x38,0x3b,0x3e,0x40,0x43,0x46,0x49,0x4c,
0x4f,0x51,0x54,0x57,0x5a,0x5d,0x60,0x63,0x67,0x6a,0x6d,0x70,0x73,0x76,0x79,0x7c};
void startPlayback()
{
pinMode(outputPin, OUTPUT);
// Set Timer 0 Fast PWM Mode
// WGM = 0b011 = 3 (Table 14-8)
// TOP = 0xFF, update OCR0A register at BOTTOM
TCCR0A |= _BV(WGM01) | _BV(WGM00);
TCCR0B &= ~_BV(WGM02);
// Do non-inverting PWM on pin OC0A, arduino digital pin 6
// COM0A = 0b10, clear OC0A pin on compare match,
// set 0C0A pin at BOTTOM (Table 14-3)
TCCR0A = (TCCR0A | _BV(COM0A1)) & ~_BV(COM0A0);
// COM0B = 0b00, OC0B disconnected (Table 14-6)
TCCR0A &= ~(_BV(COM0B1) | _BV(COM0B0));
// No prescaler, CS = 0b001 (Table 14-9)
TCCR0B = (TCCR0B & ~(_BV(CS02) | _BV(CS01))) | _BV(CS00);
// Set initial pulse width to the first sample.
OCR0A = pgm_read_byte(&sinewave_data[0]);
// Set up Timer 1 to send a sample every interrupt.
cli(); // disable interrupts
// Set CTC mode (Section 15.9.2 Clear Timer on Compare Match)
// WGM = 0b0100, TOP = OCR1A, Update 0CR1A Immediate (Table 15-4)
// Have to set OCR1A *after*, otherwise it gets reset to 0!
TCCR1B = (TCCR1B & ~_BV(WGM13)) | _BV(WGM12);
TCCR1A = TCCR1A & ~(_BV(WGM11) | _BV(WGM10));
// No prescaler, CS = 0b001 (Table 15-5)
TCCR1B = (TCCR1B & ~(_BV(CS12) | _BV(CS11))) | _BV(CS10);
// Set the compare register (OCR1A).
// OCR1A is a 16-bit register, so we have to do this with
// interrupts disabled to be safe.
OCR1A = F_CPU / SAMPLE_RATE; // 16e6 / 8000 = 2000
// Enable interrupt when TCNT1 == OCR1A (p.136)
TIMSK1 |= _BV(OCIE1A);
sample = 0;
sei(); // enable interrupts
}
void setup()
{
startPlayback();
//initialize serial communication at 4800bit per second;
Serial.begin(4800);
pinMode (led,OUTPUT);
}
void loop()
{
int i;
for (i=0;i<N;i++) {
voltageValue[i] = analogRead(A0);
voltage[i] = voltageValue[i] * (5.0 / 1023.0);
if (i>0&&voltage[i]-voltage[i-1]>=0.05){
PressStatus=1;
digitalWrite(led,HIGH);
Serial.println(voltage[i]);
}
else {
PressStatus=0;
digitalWrite(led,LOW);
Serial.println(voltage[i]);
}
}
}
// This is called at SAMPLE_RATE kHz to load the next sample.
ISR(TIMER1_COMPA_vect) {
if (PressStatus==1){
if (sample >= sinewave_length) {
sample = -1;
}
else
{
OCR0A = pgm_read_byte(&sinewave_data[sample]);
}
++sample;
}
}