การวัดความสูงจากระดับน้ำทะเล

[นวัตกรรม]

จาก http://www.electoday.com/bbs/redirect.php?tid=2418&goto=lastpost

Arduino + MPX4115

MPXAZ4115C6U-ND
เป็นตัว SENSOR วัดแรงดัน ขนาด 2.2 - 16.7 PSI  ตัวถังแบบ PORTED SOP  ให้ OUTPUT เป็นแรงดัน 0.2 - 4.8V
ราคา ...  *850 บาทซื้อได้ที่ ETT

โค๊ด:

   #include<math.h>
    #include<stdio.h>

    //
    int  Voume1 = 0; //Voume0 = Analog Pin-0
    float A1= 111.11111,b1=9.0555556;  // Mpx 4115
    float X1,ADC1,V1,Y1,error=.5;
    double P,P0=101.325,aa=0.190284,kk=145366.45;
    double hm,hal,sumADC1;

    void setup()                                    
    {
      Serial.begin(9600);                          
    }

    void loop()                                    
    { int i;
    for(i=1;i<=100;i++)
    {
      ADC1 = analogRead(Voume1);
      delay(1);
      sumADC1 +=ADC1;
    }
      ADC1=sumADC1/100;
      V1 = ((float)ADC1/1023)*5;
      X1=ADC1/1023; //MPX4115
      Y1 = A1*X1+b1+error ;  
      P=Y1;
      hal=(1-pow((P/P0),aa) )*kk;
      hm=hal*.3048;
      Serial.print(P);
      Serial.print(" kPa ");  
      Serial.print(hm);
      Serial.println(" m");
    delay(500);
    sumADC1=0;
      
    }

[นวัตกรรม]

An Experimenter's 1-Wire Barometer

จาก http://davidbray.org/onewire/barometer0.html

[นวัตกรรม]

Digital barometer

จาก http://mcs.uwsuper.edu/sb/Electronics/Baro/










PIC source code

โค๊ด:

 TITLE  "baro.asm"           ; atmospheric pressure
 List P=PIC16F684, R=DEC
 INCLUDE "p16f684.inc"

SCL EQU 2 ; Clock line setup
SDA EQU 1 ; Data line setup
CORR EQU 6832 + 186
; data segment
 CBLOCK 0x20                   
 del, cnt, temp  ; local variables
 bar:2 ; storage for pressure
 bcd:2
 i, dataIO
 ENDC

; code segment
 __CONFIG _FCMEN_OFF & _IESO_OFF & _BOD_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT

 ORG 0                 
bcf STATUS, RP0 ; switch to BANK 0
clrf PORTA ; initialize PORT A
clrf PORTC ; initialize PORT C
movlw 0x07
movwf CMCON0 ; comparators OFF
bsf    STATUS, RP0     ; switch to BANK 1

  ; ADC and ports configuration
clrf TRISA ^ 0x80 ; configure PORTA for output
movlw b'011100'
movwf TRISC ^ 0x80
movlw b'10000000'
movwf ANSEL ^ 0x80 ; configure RC3 as analog input
movlw b'01110000' ; set ADC Frc clock
movwf ADCON1 ^ 0x80
bcf    STATUS, RP0 ; back to BANK 0
movlw b'00011101'
movwf ADCON0 ; left justify, Vdd Vref, AN7, On


loop
movlw 250
movwf del
call delay ; 250 msec delay
movlw 250
movwf del
call delay ; 250 msec delay

bsf ADCON0, GO ; start ADC operation
btfsc ADCON0, GO ; and wait for its completion
goto $-1
movf ADRESH, w ; get high 8 bits of ADC
; movlw 250

; compute bar*6 + CORR
movwf bar ; multiply bar by 6
clrf bar+1
rlf bar, f ; bar *= 2
rlf bar+1, f
bcf bar, 0
addwf bar, f ; bar *= 3
btfsc STATUS, C
incf bar+1, f
rlf bar, f ; bar *= 6
rlf bar+1, f
bcf bar, 0

movlw low CORR ; add corr constant
addwf bar, f
btfsc STATUS, C
incf bar+1, f
movlw high CORR ; bar = pressure*10
addwf bar+1, f ; (max 4 decimal digits)

call baro2BCD
; movlw 5
; addwf bcd+1, f
call writeMSG
  goto loop ; endless loop


; procedures
baro2BCD
movlw 16 ; 16-bits
movwf temp ; make cycle counter
clrf bcd ; clear result area
clrf bcd+1

b2bcd2
movlw bcd ; make pointer
movwf FSR
movlw 4
movwf cnt

; Mike's routine:
b2bcd3
movlw 0x33
addwf INDF, f ; add to both nybbles
btfsc INDF, 3 ; test if low result > 7
andlw 0xF0 ; low result >7 so take the 3 out
btfsc INDF, 7 ; test if high result > 7
andlw 0x0F ; high result > 7 so ok
subwf INDF, f ; any results <= 7, subtract back
incf FSR, f ; point to next
decfsz cnt, f
goto b2bcd3

rlf bar+0, f ; get another bit
rlf bar+1, f

rlf bcd+1, f ; put it into bcd
rlf bcd+0, f
decfsz temp, f ; all done?
goto b2bcd2 ; no, loop
return ; yes

msg1 ; first message to display
addwf PCL, f
dt " Pressure:", 0

msg2 ; second message to display
addwf PCL, f
dt " mmHg", 0

;*******************LCD interface
writeMSG
; output of the top row (msg1)
movlw b'10000001' ; clear display
call writeLCD

clrf i
L1 movf i, w
call msg1 ; get the next char
iorlw 0 ; end of string?
btfsc STATUS, Z
goto L2 ; YES - jump out of the loop
call writeLCD ; NO - send it to LCD
incf i, f ; update the char index
goto L1

L2 movlw 0xC0
call writeLCD ; move the cursor to the second line
clrf i ; clear the index of the second string

; output the bottom row
swapf bcd, w
andlw 0x0F
addlw 48 ; ASCII conversion
call writeLCD
movf bcd, w
andlw 0x0F
addlw 48
call writeLCD
swapf bcd+1, w
andlw 0x0F
addlw 48
call writeLCD
movlw 46 ; decimal point
movwf dataIO
call writeLCD
movf bcd+1, w
andlw 0x0F
addlw 48
call writeLCD

; output msg2
L3 movf i, w
call msg2 ; get the next char
iorlw 0 ; end of string?
btfsc STATUS, Z
goto L4 ; YES - jump out of the loop
call writeLCD ; NO - send it to LCD
incf i, f ; update the char index
goto L3

L4 return

writeLCD ; write byte in W to the LCD line
movwf dataIO
movlw b'111001'
andwf PORTC, f
movlw 0x87 ; setup FSR to point to TRISC
movwf FSR
bsf INDF, SCL ; make sure that clock is high
movlw 8
movwf cnt ; bits counter

w_loop
btfss PORTC, SCL ; wait for release of the clock line
goto $-1

bcf INDF, SCL ; set clock low
rlf dataIO, f ; get the rightmost data bit
btfss STATUS, C
bcf INDF, SDA
btfsc STATUS, C
bsf INDF, SDA ; now the data bit is on the line
goto $+1 ; short delay
bsf INDF, SCL ; raise clock up

movlw 6 ; a 20 usec delay
addlw -1
btfss STATUS, Z
goto $-2

decfsz cnt, f
goto w_loop ; repeat this 8 times
return

delay ; a delay for del milliseconds
movlw 200

sublw 1 ; this loop takes 5us*200 = 1ms
sublw 0 ; for PIC @ 4 Mhz
btfss STATUS, Z
goto $-3

decfsz del, f
goto delay
return

 end