Help measuring distance....

[GrandPa]

Hi,


I think you should consider using PIC2331/2431/4331 or 4431.
Those PICS have a built-in motion feedback module. I think the "velocity feedback module" will do exactly what you want. Look at the datasheet for more details.

BTW: Downside is that the ADC module is a bit of pain in the ... to use. Since it's not completely integrated with PBP.

J-P

[sayzer]

WhyNot use a traditional way;

' 9 Pulses come in in 0ne meter.
' Measure the time it takes for 9 pulses to come in.
' Timer0 is in Counter Mode.
' Timer1 is in Timer Mode.

' Set your prescaler and other TMR settings etc... here.

Start:

    TMR1ON = 0      ' Stop TMR1.
    TMR1H = 0       ' Clear TMR1.
    TMR1L = 0              '....
    Speed = 0       ' Speed is a Word variable.
    TMR0 = 0        ' Clear TRM0.    

    WHILE TMR0 = 0 : WEND       ' Wait for an incoming Pulse (First pulse does not count).
    TMR1ON = 1                  ' Start Timer1 Module.
    WHILE TMR0 < 9 : WEND       ' Count 9 pulses.
    TMR1ON = 0                  ' Stop Timer1 at 9th Pulse.

    Speed.LowByte = TMR1L
    Speed.HighByte = TMR1H
    
    ' The car took 1Meter in "Speed" mS.    Example: 1 Meter in 100mS.
    Speed = 60000 / Speed                   ' Speed = 60,000mS / 100Ms => 600 Meter in One Minute.
    Speed = Speed * 60                      ' Speed = Speed * 60Mins   => 600Meter * 60Mins = 36,000Meter. => 36Km/Hr
     
    LCDOUT $FE,1,"Speed:", dec5 Speed,"Km/Hr"
    
    
Goto Start

[HenrikOlsson]

Is it just me or didn't he say he want to measure distance? IE distance, not speed. Yep, I'm sure, he said distance...

I may have misunderstood though....

;-)

/Henrik Olsson.