Asked — Edited
Resolved Resolved by ptp!

Function For Counting Pulses On A Digital Input

I need to count the number of times a digital input detects state changes within a specified time window (100ms to 1000ms). Any suggestions?

Thanks.


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#1  

with a loop, use the WaitForChange function to detect the change of the digital input.

I will post a code example when I get to my computer.

PRO
USA
#2  

@rz90208: WaitForChange evaluates the condition every 10 ms, then you have the EZ-Script parser and communications overhead.

@Jim Milan: if you need accuracy and/or the transitions are fast you will need a micro-controller e.g. Arduino, PIC.

ARC (Desktop/Mobile) applications runs the logic code, EZB only handles the hardware.

you can try the EZ-Script maybe can work if your requirements are not "Real Time" :


#Monitor Port D23 changes for one second")

$start_date=$date
$last_value=GetDigital(D23)
$number_of_changes=0

:loop
$current_value=GetDigital(D23)

if ($current_value!=$last_value)
  $last_value=$current_value
  $number_of_changes=$number_of_changes+1  
endif

$timespan=CDateTime($date)-CDateTime($start_date)
$timespan_sec=FmtTimeSpan($timespan, "ss")

if ($timespan_sec<1)
  #Same timeout used in WaitForChange(...) 
  Sleep(10)
  Goto(loop)
endif

print("number_of_changes: " + $number_of_changes)

#3  

@ptp Thanks, your code worked. It was the kick start that I needed. I'm using a Parallax X-Band (10.525 GHz) Motion Detector in my latest ARMadeus robot. The unique feature of this sensor is that is capable of detecting motion though walls. I understand the 1 second limitation by using the system $date function. Since the sensor has an enable pin, I may tinker with a combination of Set(DigitalPort, ON/OFF) and Sleep(ms) commands to generate an adjustable enable pulse.

Jim Milan