Hii
The system is like this.
Arduino 1
using the start button the arduino 1 will transmit signal and also a timer will start.

Arduino 2
the arduino 2 will receive the transmitted signal by arduino 1 once the arduino 2 received the signal it will transmit another signal back to the arduino 1.

Arduino 1
the arduino 1 will received that signal then stop the timer. Then the arduino 1 will determine the time.
then using formula we can get the distance.

In this system only my doubt is how to know time. I don't know about arduino timers. So please say that how can I measure this tome.

 

As Arduinos are usualy programmed in "C" it is difficult to measure times in the order of microseconds as you don't know how long a line of code takes to execute. If you are measuring time in the order of days you will not have a problem as the time taken to run the code will not be significant in your results. You need to give an idea of the time you are trying to measure.

Les.

 

The arduino has counters for microseconds and milliseconds running continuously.
If the time you want to measure is within the ranges of these counters then you can record the counter value when you transmit and again record the value when you receive. Then the transit time is the difference between the two values.
https://www.arduino.cc/en/reference/micros
https://www.arduino.cc/en/Reference/Millis

 

Is there any other method except this?

 

I am sure there are many other methods.
For instance, you have a timer external to the arduino and the arduino sends start and stop signals to the external counter.

 

As Arduinos are usualy programmed in "C" it is difficult to measure times in the order of microseconds as you don't know how long a line of code takes to execute. If you are measuring time in the order of days you will not have a problem as the time taken to run the code will not be significant in your results. You need to give an idea of the time you are trying to measure.

Les.

You can also program an arduino in assembler (though it is definitely more effort) and then you can do timing by knowing how many instruction cycles have elapsed.

 

What are typical distance that you hope to measure?

 

It will be the range between 2 to 400 meters.
Because the boards will not be constant.
They will be moving.

 

It might be helpful if you shared why you are looking for another method. It could clarify the real world environment. Or it might provide some information on your skill set.

Just wondering...

 

I don't get what you trying to say.

 

@djsfantasi is asking why you are not accepting the suggested method and asking for some other way ?
What is it exactly you are trying to do ?
What is your experience in building ckt's or what is your programing skills ?

 

This two methods I have tried but not got output so I was asking for any other method.

 

It might help if you show us what you did so we can show you where you went wrong.

Another way is to buy a measuring instrument.

And again you did not answer the questions.
If you want help answer the questions that we ask or we might just ignore you.

 

Hi Albert,
I mostly work with assembler (Mostly 8 bit PICs and Atmel chips.) I find it much easier to understand than programming in "C". If the TS wants another method he could use assembler which would give him direct access to the timer/counter modules.

Les.

 

Just to give you a feel for the problem: 2 meters to 400 meters at about 1 foot per nanosecond amounts to about six nanoseconds to 1.2 microseconds time of flight. I suspect that if using on-chip timers the granularity of your time measurement is going to very large. Using an AVR clocked at 20 Mhz the timer's granularity will be about 15 meters. There will also be overhead in the transmitter and receiver circuitry which may be close enough to being constant that they can be subtracted out. I don't know about other processor families that work with Arduino.

An external timer, possibly an anlog circuit can give much finer granularity.

 

Is the communication via radio, wires, sound, or what?

 

Good point AlbertHall! For all we really know it could be ultrasonic, in which case timing would be a whole lot easier

 

Hi,

Yes the usual method is to use the count usually called "millis()" or "microseconds()" or something like that.

If that doesnt work, then we need more detailed information about the project or at least hear about what did not work about it.

 

Adding a gps tracker to each unit would probably be cheaper.

 

Hi
I want to use external timer. Anybody can suggest any timers for this purpose.