I created a contactless reset switch for the 16F628A. It consists of
two(to compensate for different light situations) Light Dependent
Resistors (and two resistors to create a reference) and a comparator
to compare both.

Another option is a pushbutton and no LDR.

I ask you, dear reader, about your pros and cons regarding one option
compared with the other one.

My application is to work in a relatively dark environment and a light
one.

As a starting point, my pros:

LDR Pro:

- classy

- no contact (compared with the switch), so no abrasion.

- using is effortless

- fast change of states(only depending on your hand's speed)


Pushbutton Pro:

- Having used a LDR often, it might not have the same value as the one
being used as a reference. So light and dark changings cause a value
change when being exposed to the same light intensity.

- Secure under any circumstances, push means contact, release means
none.

- Lasts Millions of pushes and releases.

- I can always be sure about its state. Either the cylinder is inside
or not.

Regards

TK.

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