help me to identify this microcontroller. please :(

[JonSea]

What resolution do you need? In other words, how closely do you want to measure 100 meters?

If you can only resolve 600 ns, you can say the building is:

1. Less than 50 meters long, or
2. Between 50 meters and 150 meters, or
3. Between 150 and 250 meters long, etc.

If you want to measure the building to the nearest meter, you have to be able to resolve a 6.6 ns difference. If you want a finer resolution, you have to resolve even smaller periods.

 

[Rafael143]

thanks

 

[JonSea]

Same question still applies. See the first line of my last message.

 

[Rafael143]

thanks

 

[alec_t]

If you are using a counter to measure a time period with 6nS resolution you need a clock frequency of at least 1/(6 x 10^-9), i.e. ~170MHz.
As an alternative to counting you might like to consider the 'chirp radar' method (google that), which essentially involves transmitting a swept frequency burst (chirp) of RF and comparing the received echo with the transmitted signal.

 

[JonSea]

I can't believe this topic spans 3 pages and you have not answered the question about resolution. Lets try it this way...which isn't quite correct but maybe you'll understand.

How accurately do you need to measure the building? Do you need to say it's closer to 100m than 50m? It's about 90m, 100m, 110m? Or to the nearest meter? 100m, 101m, 102m? Even better than that? 101.1m?

Until you can figure this out, you're stuck.

 

[DerStrom8]

I agree with you Jon. I asked the OP a while ago to research and learn what "resolution" means, and I think he still has not done that.

 

[kubeek]

Resolution, not range. With 600ns clock you will be able to tell whether the distance is 0 or 100 or 200 or 300 etc. meters. To be able to tell whether it is 310 or 320 m you need 60 ns clock.

 

[Rafael143]

thanks

 

[JonSea]

If you want to measure to a tenth of a meter, you need to be able to resolve a time of 0.6 nano-second or less.

If you're using a microcontroller, it will take at least a few clock cycles to sense the pulse.

0.6 nano-sec corresponds to a frequency of 1.7 giga-Hertz. Measuring the transit time doesn't appear to be practical, at least not with a simple microcontroller system.

 

[Rafael143]

thanks

 

[JonSea]

It's been explained numerous times in this thread already. Please read what people have taken their time to post.

 

[Rafael143]

thanks

 

[DerStrom8]

sir I'm just asking the formula did you use to come up with 0.6nano-seconds, after that this thread is done. thanks to all who help me.

You calculate it using the speed of light.

 

[Rafael143]

thanks

 

[JimB]

I think you mean speed of light.
JimB

 

[DerStrom8]

Do you know what the speed of light is? If so, you should be able to do the calculation yourself, assuming you have a very basic understanding of simple Algebra.

Also, don't threaten to make the thread longer. That won't help you get your answers any faster. Quite honestly, I don't care how many pages this thread has

 

[DerStrom8]

I think you mean speed of light.
JimB

Quite right, wasn't thinking straight there.

Fixed now, thanks!

 

[Rafael143]

i know sir. what the problem is every time i asked a question you will answer me a question. you will notice it when you read the whole thread . every time i ask you give me your lecture but where is the answer? now I'm just asking the formula sir. if you don't want to share it, its okay. I'm just a normal people trying to learn.

by the way, thanks a lot to Mr. alec for answering my questions.

 

[JonSea]

How about posts 18, 21 & 33 to start?


Or look at one of the links that DerStorm's search leads to:

https://www.instructables.com/id/Distance-measurement-with-radio-waves/