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5 to 30 cm ultrasnoic senosr.

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boon1987

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hello everyone,

I am currently facing problem with building the the circuit for ultrasonic sensor. I am currently build a project for the following robot car follow leading robot car. To keep the safe distance between of following robot car and leading robot car, i want to use the ultrasonic sensor to sense this distance.

So i want to build the ultrasonic sensor to sense the leading robot car. The sensing range of ultrasonic sensor should be from 5 cm up to 20 or 30 cm cm. My problem is regarding the blind zone of the ultrasonic sensor. After reading many article related to ultrasonic sensor, i found most of their sensing range is more than 30 cm. Below the 30 cm is the blind zone.

So i am facing problem with build a circuit of ultrasonic sensor with sensing range between 5 cm to 20 cm(or 30 cm). I don't know how to build the circuit. What is the factor that affect the sensing range of the ultrasonic sensor. Can anyone give me some assistance for the schematic? I just want to build a ultrasonic sensor can meausre the distance between upt to 30 cm only.

By the way, i am using 40 kHz ceramic ultrasonic sensor .

I attach the schematic below and datasheet for ultrasonic sensor.

I would really appreciate to the person helping me. Thank in advance.
 

boon1987

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hello....nobody reply?

Please, provide me some assistance regarding this circuit.

Is the range of ultrasonic sensor that can sense is depend on the transmitter only or receiver only? How do i adjust the range distance that ultrasonic can sense ?Please provide me some explaination.

Beside. on the receiver part, the shematic for receiver part i found and post the post above is use LM324 as amplifier and comparator. Is it enough? I found many article use one IC for low noise amplifier and another IC for comparator. Is it nessecary?
 

FvM

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A two transducer 40 kHz US system should be basically able to sense distances in the intended range. 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.

The development of a good echo sensor circuit and software (if you aren't able to copy an existing design), would be a demanding project on it's own. So I wonder, if your project plan has enough room to go deeper into the topic.
 

pranam77

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boon1987 said:
Is the range of ultrasonic sensor that can sense is depend on the transmitter only or receiver only? How do i adjust the range distance that ultrasonic can sense
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
 

boon1987

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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
.

I found another schematic from the link below. Just click the link for the schematic.

http://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.
 

FvM

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Just modules are not responsible for the possible maximum distance measurement
The addressed problem was minimum distance, if I understand right, but also it's not just a modules question.
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
You have been discussing dead zones of US sensors. I expressed my opinion, that downto 5 cm is feasible with 40 kHz operation frequency system utilizing two transducers. You possibly know, that there are also single sensor systems. Dead zone is a more serious issue with these.

I don't understand the zero crossing and crosstalk
Zero crossing is the detection principle in the presented circuit. The crosstalk issue is discussed in the circuit description, without using the term.

The new circuit is using envelope detection (in principle), but it has errors. When I mentioned to have seen better circuit examples, I forgot about the huge amount of garbage circuits on the internet. I try not to remember them, usually.

can you provide me the basic good schematic
Sorry, I'm not presently engaged with this kind of applications.
 

neos

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HIIIIIIIIII

I am NEOS, I am doing projects in Biometrics, right now i concentrating in Ultrasonic . can you pore some basic things in Ultresonic.
 

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