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Topic: Infrared sensor + Comparator still subject to debounce? (Read 905 times) previous topic - next topic

btfdev

Hello Team

In the lab we have a setup using Infra red object sensor (QRD1114) sensing a rotating shaft, we added a comparator (LM311) so we get an absolute output.

Now before feeding the output to Arduino. A silly question. Will this setup subject to debounce? or bouncing is only applies to a mechanical switch?

Thanks, BTFDev

srinathdevelopment

well the usual way to use comparators is to add adequate hysterisis to its circuitry to prevent bouncing. If you are doing this, you should see smooth transitions...

are you trying to measure the speed of a rotating shaft? if so, you may want.to check if your detector has adequately fast response time since the.detector is phototransistor based and i have often read that phototransistor response times are slow vis-a-vis reverse biased photodiodes
Ardgrafix6100 - A fast, full-featured Arduino graphics driver for Nokia 6100 LCDs http://code.google.com/p/ardgrafix6100/

srinathdevelopment

oh... and btw, you should use timer interrupts on arduino to accurately sense when the output from your comparator is changing if you're talking about fast speeds here
Ardgrafix6100 - A fast, full-featured Arduino graphics driver for Nokia 6100 LCDs http://code.google.com/p/ardgrafix6100/

MarkT


oh... and btw, you should use timer interrupts on arduino to accurately sense when the output from your comparator is changing if you're talking about fast speeds here


I think "pin interrupts" was meant, not "timer interrupts"...
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