Don't know how to make an ultrasonic sensor circuit....

[zxcvb]

TL;DR Summary

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.

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?

 

[Baluncore]

Can this step be achieved by MSP430

1. The microcontroller must be programmed to generate a 40 kHz signal.

What function?

2. The only connection between the TX and RX circuits is in the software.

but it is for a 25Khz sensor. Can I use it?

3. Yes. There are no frequency dependent components in the circuit.

What are the values of resistors and capacitors based on?

4. Values are selected to minimise waste of power, to minimise electrical noise, and not be affected by the input bias currents.