LM324 IR detector circuit

[cosminnci]

Hello,

In my project I need to create 2 ir beams that are fed into a uc digital input and analyzed. So far I found a gate automation module and recreated the schematic in the idea to duplicate for the other channel as well, but somehow there is timing difference between the 2.
My knowledge in op amps is not very good, from the schematic I deduced it has a band-pass filter and amplifier level, a comparator level and an logic inverter level, but not sure if they are applied properly in my design.
The input of the circuit is from a fototransistor or photodiode I presume the first, the type is unknown.
I already made a few revisions, but it`s like the 2 identical circuits do not behave the same way, like the treshold values varies and the uc receives incorect order of feeds and messes the logic.
is my approach incorrect by using 2 identical circuits or should be used 1 with identical reference?
also I noticed that the dividers are very sensitive to voltage changes so I should also have a ldo regulator also included.

regards,
Cosmin

[oldway]

Easier to read

[Audioguru]

The lousy old  LM324 works poorly above only 2kHz. Modern audio opamps like the OPA4134 work perfectly to above 200kHz. 

[cosminnci]

The ir modulation is regular pwm somewhere from 500Hz to 1,2Khz this is the sensitivity range I found.
it should be safe from high freq remote control ir.
I tried to understand the stages
ic2c and ic2d should be the bandpass filter with amplification
ic2b should be the comparator and ic2a only an signal inverter.

the 2 rectifier diodes and the caps should filter the pwm input and allow the comparator to have a steady high or low.

am I correct about the above?

regards,
Cosmin