I am preparing to use an ultrasonic transmitter and receiver to make an ultrasonic sensor circuit

[RachelAnne289]

Hello everyone, I am studying abroad and I am working on a speedometer project.
I am preparing to use an ultrasonic transmitter and receiver to make an ultrasonic sensor circuit, and then connect it with the single-chip microcomputer msp430 to realize the functions of speed measurement and numerical display.

I am temporarily in charge of the hardware module.
I don't know much about circuit diagrams, and I have many questions to ask.
1. I chose a 40Khz ultrasonic transmitter and receiver. Does the circuit I need to generate a frequency of 40Khz? Can this step be achieved by MSP430?
2. What circuit do I need to make between the transmitter and receiver? What function?
3. I found this circuit design on the Internet, but it is for a 25Khz sensor. Can I use it?
4. What are the values of resistors and capacitors based on?

 

[KlausST]

Hi,

My recommendation: choose a more suitable circuit from a reliable source. (Semiconductor manufacturers, universities...)
It has many issues .... I see more problems than meaningful results.

issues:
* now OPAMP power supply, no power supply at all.
* use of unsuitable LM741 (I call it outdated since 30 years)
* unsuitable comparator without offset and without hysteresis
* problematic C2
* unsuitable R2
* ...

Klaus

 

[Audioguru]

Please attach the datasheets for the ultrasonic transmitter and receiver. The circuit must be designed to match them.
I agree that the 741 opamp was designed 53 years ago and does not work at 40kHz, it has trouble above 1kHz.

How will you measure speed? Blast transmitted 40kHz at the road and if it is not smooth then have the receiver pickup a reflection?

 

[FenTrac]

In the video you have a reference to, the ultrasonic module being used is an HC-SR04. To use it with a microcontroller, all that needs to be done is connect it
to 2 digital pins and to +5v and ground as shown in the video. Is this the module that you are proposing to use?

 

[Audioguru]

The HC-SR04 module measures distance up to only 4m, not speed.

 

[tonaleva12]

Yes I were using HC-SR04 for only speed measurement in my project also