How to build a voltmeter using Pic16f887?

cktlover said:

Code:

           [COLOR="#0000FF"]ADCResult = (ADC_Read(0) * 500) >> 10 [/COLOR]
           voltage[0] = ADCResult div 100 
           voltage[1] = (ADCResult div 10) mod 10 
           voltage[2] = ADCResult mod 10 
           display[0] = voltage[0] + 48 
           display[2] = voltage[1] + 48 
           display[3] = voltage[2] + 48 
     vout: 
           LCD_Out(1, 10, display) 
           delay_ms(50) 
     wend 
end.
Here what does this line mean to do 
 [COLOR="#0000FF"]ADCResult = (ADC_Read(0) * 500) >> 10[/COLOR]?

Click to expand...

Tahmid said:

Hi lacoste,

I present here a simple voltmeter with 16F887 (0-5v scale). But mind it, this is very basic with no input overvoltage protection. A voltage greater than 5v applied to the input will destroy the 16F887.

Source code (written in mikroBasic):

Code:

program softwarefor887Voltmeter

dim LCD_RS as sbit at RB4_bit
    LCD_EN as sbit at RB5_bit
    LCD_D4 as sbit at RB0_bit
    LCD_D5 as sbit at RB1_bit
    LCD_D6 as sbit at RB2_bit
    LCD_D7 as sbit at RB3_bit

    LCD_RS_Direction as sbit at TRISB4_bit
    LCD_EN_Direction as sbit at TRISB5_bit
    LCD_D4_Direction as sbit at TRISB0_bit
    LCD_D5_Direction as sbit at TRISB1_bit
    LCD_D6_Direction as sbit at TRISB2_bit
    LCD_D7_Direction as sbit at TRISB3_bit

dim ADCResult as longword
dim voltage as word[5]
dim display as string[5]

sub procedure GlobInit
    ANSEL = 1
    ANSELH = 0
    TRISA = 1
    TRISB = 0
    PORTB = 0
    LCD_Init()
    LCD_Cmd(_LCD_CLEAR)
    LCD_Cmd(_LCD_CURSOR_OFF)
    LCD_Out(1, 1, "Voltage:")
    LCD_Chr(1, 16, "V")
    display[1] = "."

end sub

main:
     GlobInit
     while true
           ADCResult = (ADC_Read(0) * 500) >> 10
           voltage[0] = ADCResult div 100
           voltage[1] = (ADCResult div 10) mod 10
           voltage[2] = ADCResult mod 10
           display[0] = voltage[0] + 48
           display[2] = voltage[1] + 48
           display[3] = voltage[2] + 48
     vout:
           LCD_Out(1, 10, display)
           delay_ms(50)
     wend
end.

Click to expand...

manoj madhavan said:

Hi Tahmid,


Is it really working or just for fun?

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Tahmid said:

Of course it works. Have you encountered any problem while using this?

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Tahmid said:

It should work. Check this image:



Try to make the circuit yourself again. If you still can't do it, I'll attach the DSN file. But it's a really simple simulation and you should be able to do it easily.

Hope this helps.
Tahmid.

Click to expand...

manoj madhavan said:

But this is only for meassure 5 V DC only?


Regards

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