ultrasonic reciever/transmitter

[kangkandc]

i have a problem in ultrasonic radar projects

how can i impliment a ultrasonic transmitter/reciever circuit using a single peizocrystal for both transmiting and recieving purpose???::idea:

 

[FvM]

ultrasonic radar project

Look at commercial US proximity switches or distance sensors. Most of them do.

 

[liakofan]

ultrasonic radar

I have another kind of problem that maybe someone can help me with.
My problem is that i have to measure distance using an ultrasonic receiver ,in order to measure the water length of a small tank of water,but i have to use only analoge means,no microcontrollers , can anyone help me??
i thought about using a counter that would start counting when the transmiter send a pulse and stoped when the receiver is activated and then transform time into distance somehow.Am i even close?
PLZ help if you can
THNX!

 

[vfone]

project on ultrasonic radar

https://www.electronics-lab.com/projects/sensors/007/index.html

 

[FvM]

ultrasonic transmitter

Although the project claims the title utrasonic radar, it's actually a common CW doppler intrusion detector (And a poor design, cause it doesn't utilize synchronous demodulation, by the way). So it doesn't help for the said problem.

The question is a bit confusing to me, cause I didn't regard a counter as an analog device, up to now. It's obviously digital, although not using a processor

I have a fine true analog echolot on my boat. It uses a LED mounted on a hand rotated by a motor in a circular window. The US pulse is send a the 12 o'clock position and the LED displays the echo signal intensity. It also visualizes muddy ground and fish swarms. The range can be switched by changing the motor speed.

 

[vfone]

ultrasonic reciever

The schematic above was only for reference (the same as the attached one).
Ultrasonic radar is fine to start your project. Any radar type (microwave or ultrasonic) use a Transmitter and a Receiver. The resulting delay between transmitted and received waves can be counted with a simple digital counter (with no microcontroller inside).

 

[Jameel007]

I am trying to make an ultrasonic motion detector. For that i need the ultrasonic transducer pair. In my country it is quite unavailabe in the market. So is there any way to work it out without the transducer pair??

 

[FvM]

You should check the data of the transducers that are available for you, and see, what's possible with these. There are considerable differences in terms of operation frequency, bandwidth, directivity, impedance. Separate transmitter/receiver designs allow an easier signal processing and are better suited for continuous (CW) operating doppler sensors. Single transducer designs are mostly used for radar like time-of-flight sensors. But they are less sensitive for motion detection applications, I think.

Ultrasonic motion detectors have been used as burglar alarms before PIR sensors came up. But they are rather succeptible to false alarms, e.g. caused by movement of the air.