nobtiba
Newbie level 1
I want to make an infrared sensing circuit. This is the idea:
A LED will emit light to a paper for example, this paper have black and white line next together. The light beam will reflext different (weak or stronger) when meeting black or white light. The reflext beam will fed into an infrared sensing diode next to the LED. By this method, the output of the sensing diode will have different current whed we move the paper. This current will fed into a comparator circuit using an op-amp like LM324 to make square wave output, this pulse will be count by timer/counter of AT90S8535.
Is there some infrared sensing circuit like that for reference ? Did any body do this or happen to know where to look for this ?
A LED will emit light to a paper for example, this paper have black and white line next together. The light beam will reflext different (weak or stronger) when meeting black or white light. The reflext beam will fed into an infrared sensing diode next to the LED. By this method, the output of the sensing diode will have different current whed we move the paper. This current will fed into a comparator circuit using an op-amp like LM324 to make square wave output, this pulse will be count by timer/counter of AT90S8535.
Is there some infrared sensing circuit like that for reference ? Did any body do this or happen to know where to look for this ?