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How to can I use BPW77NA photo transistor to count an object ?

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I need to count objects using cd4510 counter.

I see I can use photo transistor to clock the counter when object pass.

I have BPW77NA phototransistor.
How can I use it with my project ?

Regards :)

schmitt trigger

Well-Known Member
It goes without saying, that you need an IR beam, its wavelength matched to the phototransistor's peak detection, which will be interrupted when the objects being counted crosses it.

Having said that, I would use a phototransistor with a visible-light filter, which the BPW77 does not have. Otherwise stray light may falsely trigger it.
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