Malfunction of Ultrasonic Motion Detector

[lovesaints]

View attachment 64218
As you can see the circuit diagram above,I had build up the circuit like 4 times and keep checking the circuit on breadboard, but the circuit still cannot function as well.Altought I discuss with my classmates,they also cant figure out why the circuit isn't function well

The BZ1 is a 40kHz ultrasonic receiving transducer
BZ2 is a 40kHz ultrasonic transmitting transducer
and the XTAL1 is a 40kHz crystal.

The code of both the transducer is 400SR/160 and 400ST/160.

I've bought all the component with same value and same code.But why it isn'nt showing the well result?izzit the transducer not working well on breadboard?

Hope you guys can give me some clue. Thanks.

 

[colin55]

The first thing you have to do is look at the waveform on the transmitter with a CRO. It only has 2 outputs on the device and you will have to see if the 4049 has sufficient driving-power to deliver a signal. If you don’t have a CRO, put the output into a 4017 and listen to the output of the 4017 with 16R earpiece or piezo diaphragm.

 

[audioguru]

You are using a lousy old LM324 quad opamp that operates poorly above only 2kHz because it is the first LOW POWER opamp ever made (which causes low performance). It works pretty well at DC and at very low frequencies.
Instead you should use a normal fairly modern opamp that works perfectly up to 100kHz (there are thousands of them available).

Your 5V supply is very low for most opamps.
An MC34071 single, MC34072 dual or MC34074 quad opamp works perfectly from a supply as low as 5V and at up to 100kHz.

The many rows of contacts and connecting wires on a breadboard pickup a lot of low frequency mains hum. Build the circuit on a pcb or with a compact stripboard layout instead.

 

[lovesaints]

Thanks, i will retry it with quad opamp

 

[audioguru]

Thanks, i will retry it with quad opamp

The LM324 in the original project already is a quad opamp. But it is old and has poor performance.
I listed much better opamps and one is also a quad.