The discussed circuit isn't suited for this purpose, I fear. As a major disadavantage, it senses zero crossings only and doesn't utilize the amplitude respectively the envelope of the received signal. That makes it particularly susceptible to crosstalk from the transmitter part. I remember to have seen much better circuit examples, but I don't have any at hand now.
Thank for replying.
so basically, the schematic i post in PDF file above is not suitable for my purpose. And i don't understand the
zero crossing and crosstalk you mentioned in your post.
I also not understand the senstence in the quate below. Can you explain futher?
A two transducer 40 kHz US system should be basically able to sense distances in the intended range
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I found another schematic from the link below. Just click the link for the schematic.
https://hobby_elec.piclist.com/e_pic6_61.htm
According to the designer of the circuit from link above, this circuit can sense the range above 30 cm to several meter. I don't care the upper limit of the sensing range but i concern with the lower limit of the sensing range. I want it to start from 5 cm to 30 cm or above 30 cm. I am concerning the lower limit.
So what can i do to modify this circuit? If possible, can you provide me the basic good schematic and teach me how to adjust the circuit to the desired sensing range?
Thank for replying me, friend.
Added after 9 minutes:
Thank you for replying, paranam77.
I didnt see the schematic posted in your last post. Anyways....Just modules are not responsible for the possible maximum distance measurement but the power you transmit through the TX module, Receiver sensitivity, and the obstacle on which the waves reflect, also plays a vital role in determining the same. Cheers
My scehamtic is put within the PDF file. You need to log in to view the file.
The power of TX module and reciever sensitivity you mentioned were understood in term but not technically. Can you provide me some schematic and teach me how to adjust those things.
Thank you.