I am using D203B model of PIR and I used the circuit that was suggested on its datasheet (first pic). I do not know what the problem is, as the output (pin the 8 and 14) of op-amp (LM324)is always on (which is connected to the transistor and LED). In fact, It does not react based on PIR output as I disconnected the PIR from op-amp and the output of op-amp was still on. By the way, I have checked LM324 and it was healthy so problem is in my circuit. Here are my circuit schematic and PCB (2nd and 3rd pics). I appreciate you, if you realize the problem.

 

Hi,
With the PIR sensor disconnected, take the signal (S) to the +12v via a 1k0 or similar, see if the output goes low.
Good luck...........

 

Hi Saeed,
Do you have Fresnel Lens over the DB203 photo sensor ?
E

 

Hi,
With the PIR sensor disconnected, take the signal (S) to the +12v via a 1k0 or similar, see if the output goes low.
Good luck...........

S pin of sensor is around 0.8 which I think it is normal. Next, I should say there is a problem in the first V ref (pin2) as I have no stable signal on it so first v out (pin 1) is zero.

 

Hi saeed,
This is a LTSpice simulation of your circuit.
Do you have an oscilloscope?
E

 

Hi saeed,
This is a LTSpice simulation of your circuit.
Do you have an oscilloscope?
E
View attachment 323316

Thanks a lot, actually I had made a mistake in soldering and c9 had not connected to the track of pin 2 so there was not v ref on the first op amp now it is solved.

Now how can I make the time and also sensivity of output adjustable ?

 

hi S,
What time range and sensitivity?
E

 

First, if both of the opamp outputs, pins #8 and #14arehigh, then either the input is oscillating or both sections have their inputs exchanged. The voltage at pin7 should be between the voltages between the three resistor divider.midpoints.Or possibly the ends of that divider string are reversed.
In addition, I see way too much gain in the DC amplifier section driving the two opamps used as comparators. Running a low-precision opamp as a high gain DC amplifier is begging for problems.

 

hi S,
What time range and sensitivity?
E

What I mean is that the time of being on of the output. With this circuit output is on as long as it sense a motion, I want it be on for a few seconds after detecting motion. In addition, I want to be able to adjust its sensitivity to the motions.

 

First, if both of the opamp outputs, pins #8 and #14arehigh, then either the input is oscillating or both sections have their inputs exchanged. The voltage at pin7 should be between the voltages between the three resistor divider.midpoints.Or possibly the ends of that divider string are reversed.
In addition, I see way too much gain in the DC amplifier section driving the two opamps used as comparators. Running a low-precision opamp as a high gain DC amplifier is begging for problems.

I took this circuit from PIR schematic. If lm324 which is suggested is not precise, which op-amp is better to use with PIR.

 

hi Saeed,
Note the change to a simple MOSFET and a 1meg/1uF delay, you can extend the On time.
Increase value of C12 to increase On time
R17 represents the Relay coil
E

 

What I mean is that the time of being on of the output. With this circuit output is on as long as it sense a motion, I want it be on for a few seconds after detecting motion. In addition, I want to be able to adjust its sensitivity to the motions.

OK, adjusting the sensitivity will mean adjusting the gain of the amplifier stages. reducing the on time will require adjusting the RC time constant of the relay driver transistor base drive circuit. Changing the output to switch off after a short time will require the addition of a non-retriggerable timer into the switch transistor base circuit.
So now I wonder just what the application of this circuit is supposed to be.