I find I need a comparator, because I have a problem with an optical sensor triggering multiple interrupts, like this question:
However, as the market for electronics have changed, there is no shop just around the corner, only over 100km away, and I'm impatient; I'm looking in my drawers, and found 2 types of opamps: a XR082 and a MC34002
These have a voltage input of +/- 15V. Would they work as a comparator if I only feed them the Arduino voltage of 3.3V, only positive, no negative, i.e. only a tenth of the maximum voltage?
This is measured directly on the input pin of the ESP8266
I'm using this circuit (Never mind if the diode is drawn the wrong way); using the internal pullup in the ESP8266.