Hi milad,
This is a better circuit image, shows that 47uF as electrolytic.
Also, how are adjusting the Sensitivity and the ON period, note, RL2 and RT1 on this circuit.
The Cds2 is for Light/Dark sensing on some models.
Hey Eric , i’ve replaced the C3 cap to 10uF electrolytic ( it was 10uF ceramic) and now the output always zero :/ . I don’t know what’s wrong with this circuit
hi milad,
Sorry about the delay.
What voltage do you measure on pin #14 on the BISS.
When the Sensor is covered over and also when lit by the ambient light.
If you wave your hand over the sensor, does pin#14 change in voltage.?
E
Thanks for your help. Yes, i have this cover, and the source voltage on d203b is 0.6v. But something weird is that when i my plug my board to 5v adaptor its working (but not very well, i think need to change resistor and cap values) , and when i plug my board to Li-ion battery ( 4v on battery) the circuit doesn’t work.
hi milad,
If you can see these points marked with RED arrows, with an Oscilloscope, you should see a signal when you move your hands over the PIR sensor.
If you don't have a Scope a DVM may show a value,, a small change.
I have checked your circuit at the Arrow point on LTspice simulation, works OK.
Hi,
The components in the RED box are ON time setting and the BLUE Sensitivity
RT1 is a 1 mega ohm pot for Timing and RL2 is also a 1mega ohm pot for sensitivity, you need to add these potentiometers.
When you have it working OK, wait about 60 seconds for the circuit to stabilize , after switching ON the power supply, before adjusting the pots.
Hey Eric, Thanks a lot. it's working, but i have range issue. how can i make my board more sensitive on this schematic? Which one of these resistor or caps should I replace?
Hi milad,
The Gain resistors are in a BLUE rectangle, reduce the 47K to say 27K, this will increase the Gain.
The feedback resistor is already 2meg, I would not increase that, you do not want the module to be unstable.