Connecting PIR Motion Detector with RF Transmitter

[Saeedk9574]

Hi everyone,

I’m currently working on a project to create a wireless motion detector using a PIR sensor and an RF transmitter. Both circuits function perfectly when tested separately. However, when I connect them, I encounter strange behavior: the output from the BISS0001 (PIR IC) either stays high continuously or blinks erratically.

To clarify, the PIR sensor correctly produces a high output upon detecting motion, and the RF transmitter sends signals as expected when activated independently. The PIR circuit was implemented from the BISS0001 datasheet, and for the RF section, I used an RF remote control board. I traced the connections using a multimeter and designed the circuit on my board, replacing the push button with a transistor (Q4 from the schematic).

I would greatly appreciate any guidance on how to successfully integrate these two circuits. Your expertise would be invaluable in resolving this issue.

Thank you in advance for your help!

 

[betwixt]

Both schematics seem to be wrong and it will not work as shown.

The first has no oscillator to produce RF and the antenna is connected to VCC. I suspect one of the 10pF capacitors is actually a SAW resonator and there is an inductor, possibly a PCB 'coil' between C16 and VCC. There should also be a resistor or inductor between P3 and Q8.

In the second schematic, the base of Q5 is clamped by the B-E junction in Q6 so it cannot possibly produce any significant voltage at its emitter. BISS will effectively always be low so the code input to the EV1527 cannot change.

Brian.

 

[Saeedk9574]

Both schematics seem to be wrong and it will not work as shown.

The first has no oscillator to produce RF and the antenna is connected to VCC. I suspect one of the 10pF capacitors is actually a SAW resonator and there is an inductor, possibly a PCB 'coil' between C16 and VCC. There should also be a resistor or inductor between P3 and Q8.

In the second schematic, the base of Q5 is clamped by the B-E junction in Q6 so it cannot possibly produce any significant voltage at its emitter. BISS will effectively always be low so the code input to the EV1527 cannot change.

Brian.

Thanks for reply,
Actually P3 is an oscillator, because I could not find its footprint, I used a 4 pin header instead of it in the schematic.

I know I have made a mistake in the vout of BISS0001. But I do not how I should connect its output to the transmitter to transmit signal. when PIR detects a motion there is a 5v signal in the out put of BISS0001. I supposed, if I connect this 5v to the base of an NPN transistor (Q4) it must work. In addition, I used another NPN (Q5) to boost 5v signal and also for seeing detection I used Q6 and D2. Which seems I was totally wrong.
Probably I should remove Q2, Q4, Q5 and Q6, but I do not know what circuitry is correct to turn on the transmitter by the Vout of BISS0001.

 

[betwixt]

I think your design can be greatly simplified but first, please give more information about the oscillator (in place of P3) because how it works will change the schematic.

Brian.

 

[Saeedk9574]

I think your design can be greatly simplified but first, please give more information about the oscillator (in place of P3) because how it works will change the schematic.

Brian.

it is a 433Mhz crystal oscillator. And here it is the ev1527 circuit schematic based on its datasheet.