Good evening!

Can someone help me with my project?

I've been testing the ultrasonic transmitter and receiver using the breadboard for the past week. I have been trying to test the output from the transmitter and have varying frequencies. Sometimes it goes to MHz and Khz and sometimes has frequencies even if i did not introduce a source when testing the components in the breadboard, and this applies to the receiver as well.

Here are the circuits courtesy of pocketmagic from his project.

RECEIVER

TRANSMITTER

Hopefully there will be quick responses since it would really help me a lot if i could achieve this ahead of time

Thank You in advance!

 

Breadboard acts as an antenna introducing all kinds of noise and interference. You should build the thing on protoboard.

 

Breadboard acts as an antenna introducing all kinds of noise and interference. You should build the thing on protoboard.

Sir do you know which part of the receiver circuit should I connect the probe into to test the received signal? And are there any settings in the oscilloscope that I should consider?

 

Transmitter probe goes in J2.
Receiver probe goes in that symbol on far left which I guess is microphone.

 

Sir I have a video here from the same author of the circuit, he connects his probes in the transistor and to the output pins. Does that mean that I should connect the probe in the output pin in the middle in J2? or the source pin also in J2 (which is the first pin) ?

 

Yes,You should.
His circuit doesn't look like the schematics you posted.

 

Yes,You should.
His circuit doesn't look like the schematics you posted.

Actually he's using a the same transmitter but with different oscillators. The receiver is just the same as well.
I don't know why he doesn't use the ground probe, any explanation for this?

 

He is using ground probe its connected to RX board.

 

He is using ground probe its connected to RX board.

Ah, I thought you should connect the ground probe to the ground part of the circuit all the time.

Thanks a lot!

 

Ah, I thought you should connect the ground probe to the ground part of the circuit all the time.

Thanks a lot!

You should,he is probably connecting the probe to trace that is under the board.

 

You should,he is probably connecting the probe to trace that is under the board.

Sir I replaced the 2n3904 with Bc548 transistor. Both of them heats up after being supplied for a while, is this normal? or should I apply a heat sink?

I already have achieved in receiving the transmitted signal but different wavelength with the posted video above