السلام عليكم و رحمة الله
إخواني الأعزاء لقد قمت بتجريب مشروع القياس باستخدام ال ultrasonic الموجود على الرابط
http://www.micro-examples.com/public...rasonic-ranger
و لكنني لم أنجح علما بأنني نفذت الدارة بحذافيرها
و قمت بتعديل الكود الموجود لما يلائم تموضع الشاشة lcd عندي و نسخة برنامج المايكرو سي و الكود أصبح على الشكل التالي
كود:
// PIC16F877A with 8 Mhz crystal
#define PULSELEN 300
#define BUFSIZE 10
sbit LCD_RS at RB2_bit;
sbit LCD_EN at RB3_bit;
sbit LCD_D4 at RB4_bit;
sbit LCD_D5 at RB5_bit;
sbit LCD_D6 at RB6_bit;
sbit LCD_D7 at RB7_bit;
sbit LCD_RS_Direction at TRISB2_bit;
sbit LCD_EN_Direction at TRISB3_bit;
sbit LCD_D4_Direction at TRISB4_bit;
sbit LCD_D5_Direction at TRISB5_bit;
sbit LCD_D6_Direction at TRISB6_bit;
sbit LCD_D7_Direction at TRISB7_bit;
Lcd_Cmd(_LCD_FIRST_ROW);
/*******************
* GLOBAL VARIABLES
*******************/
unsigned char outOfRange ; // out of range flag : set when no echo is detected
unsigned int buf[BUFSIZE] ; // samples buffer
unsigned char idx = 0 ; // index of current sample in buffer
/*****************************************
* INTERRUPT SERVICE ROUTINE
* This ISR handles TIMER1 overflow only
*****************************************/
void interrupt(void)
{
if(PIR1.TMR1IF) // timer1 overflow ?
{
outOfRange = 1 ; // set out of range flag
PIR1.TMR1IF = 0 ; // clear interrupt flag
}
}
/************
* MAIN LOOP
************/
void main()
{
ADCON1 = 0 ; // enables ADC
TRISA = 0xff ; // PORTA as inputs
PORTA = 0 ;
TRISC = 0 ; // PORTC as outputs
PORTC = 0 ;
// TIMER1 settings
T1CON = 0b00001100 ; // prescaler 1:1, osc. enabled, not sync, internal clk, stopped
// init LCD
Lcd_Init();
Lcd_Cmd(_LCD_CURSOR_OFF);
Lcd_Cmd(_LCD_CLEAR);
Lcd_Out(1, 1, "UltraSonicRanger") ;
Lcd_Out(2, 5, "cm") ;
// init PWM Channel : 40 Khz, 50% duty cycle
PWM1_Init(40000) ;
pwm1_set_duty(128) ;
INTCON.GIE = 1 ; // enable global interrupts
INTCON.PEIE = 1 ; // enable peripheral interrupts
PIE1.TMR1IE = 0 ; // disable timer 1 interrupt
PIR1.TMR1IF = 0 ; // clear timer 1 interrupt flag
// forever
for(;;)
{
unsigned char i ; // general purpose byte
unsigned long cm ; // distance in centimeters
unsigned char str[4] ; // string for range display
// prepare timer
T1CON.TMR1ON = 0 ; // stop timer
outOfRange = 0 ; // reset out of range flag
TMR1H = 0 ; // clear timer1
TMR1L = 0 ;
T1CON.TMR1ON = 1 ; // start timer 1
PIE1.TMR1IE = 1 ; // enable timer 1 interrupts on overflow
// send pulse
PWM1_Start() ; // enable PWM output : transducer is pulsed at ultrasonic frequency
Delay_us(PULSELEN) ; // during PULSELEN microseconds
PWM1_Stop() ; // stop PWM
Delay_us(PULSELEN * 2) ; // do nothing for twice the pulse length duration to prevent false start
while(Adc_Read(1) < 1) // while no pulse detected (no signal on ADC channel 1)
{
if(outOfRange) break ; // to late, out of range
}
T1CON.TMR1ON = 0 ; // stop timer 1
PIE1.TMR1IE = 0 ; // disable timer 1 interrupts on overflow
if(outOfRange) // is overrange condtion detected ?
{
Lcd_Out(2, 8, "OverRange") ; // display overrange message
}
else if(TMR1H < ((PULSELEN * 6 * Clock_kHz()) / (1000 * 4 * 256))) // is underrange condition detected ?
{
Lcd_Out(2, 8, "UnderRnge") ; // display underrange message
}
else // good reading
{
buf[idx] = TMR1H ; // build a 16 bit value from timer1
buf[idx] <<= 8 ; // MSB
buf[idx] += TMR1L ; // LSB
// circular buffer
idx++ ; // next location
if(idx == BUFSIZE) // the end is reached ?
{
idx = 0 ; // back to start
}
cm = 0 ; // prepare centimeter averaging
for(i = 0 ; i < BUFSIZE ; i++) // for all samples in buffer
{
cm += buf[i] ; // add to sum
}
cm /= BUFSIZE ; // average samples
/*
* cm contains now the number of clock cycles
* from the start of the ultrasonic transmission
* to the first echo detection
* the duration in second is s = cm / (Clock_Khz() * 1000 / 4)
* if we admit that sound speed in the air is 340 m/s
* the distance in centimeters (forth and back) is d = s * 340 * 100 / 2
* or d = 340 * 100 / 2 * cm / Clock_khz() / 1000 * 4
* d = 34 * 2 / Clock_Khz()
*/
cm *= 34 * 2 ; // now converts to centimeters
cm /= Clock_Khz() ;
ByteToStr(cm, str) ; // convert to string
Lcd_Out(2, 1, str) ; // print string
Lcd_Out(2, 8, " ") ; // clear error message
}
Delay_ms(10) ; // 10 milliseconds delay before next sample
}
}
ولكن النتيجة هي دائما overrange
هل جرب أحدكم هذا المشروع فضلا ؟؟؟
سؤال للخبراء في مشروع ultrasonic
