I need to find a way of wireless communication without using any commercial modules

Thread Starter

dilge

Joined Dec 25, 2016
3
I am not allowed to use bluetooth, microcontrollers and stuff like that. I will simply gain DC voltage information from two sensors and send those to the one receiver. But I don't know how I can create the wireless communication between. I am told that I can use leds and stuff but that doesn't make sense??? Any creative solution or maybe just the LED way would help :)
 

MrChips

Joined Oct 2, 2009
22,101
You have failed to provide some essential piece of information.
What is the distance between transmitter and receiver?
Is it line-of-sight, i.e. no physical obstructions?
 

Thread Starter

dilge

Joined Dec 25, 2016
3
@MrChips The distance min 20cm, but 1 meter is better. No physical obstructions. I will gain two constant DC voltages and turn them into sound waves. The problem is there are two transmitters but one receiver. Won't there be any complications because of that, and how can I arrange the information coming from the trasmitters so that they won't interfere with each other??? I am suppose to find the difference in the amplitude of the soundwaves ( I will use a differential amplifier for that but again, how will I seperate the two waves from one receiver???).
 

WBahn

Joined Mar 31, 2012
26,304
You seem to be confusing things right and left. You first mentioned using LEDs and now you are talking about using sound waves. Which is it?

First you are talking about transmitting the information from two sensors to a single receiver and now you are talking about finding the difference in amplitude of these two sound waves. Which is it? What is the difference in the amplitude supposed to tell you?

It's already been suggested to encode the information in the frequency of the signal. Just use different frequency bands for each transmitter.

Beyond that, this is supposed to be YOUR project, so perhaps you might propose some techniques that YOU are considering, instead of just asking people to tell you how to do your project for you.
 

Thread Starter

dilge

Joined Dec 25, 2016
3
You seem to be confusing things right and left. You first mentioned using LEDs and now you are talking about using sound waves. Which is it?

First you are talking about transmitting the information from two sensors to a single receiver and now you are talking about finding the difference in amplitude of these two sound waves. Which is it? What is the difference in the amplitude supposed to tell you?

It's already been suggested to encode the information in the frequency of the signal. Just use different frequency bands for each transmitter.

Beyond that, this is supposed to be YOUR project, so perhaps you might propose some techniques that YOU are considering, instead of just asking people to tell you how to do your project for you.
I am sorry for causing confusions, I was planning to use leds but then I decided to use microphones. Thank you so much for your kind reply, I did not mean to make anyone do my project, I was simply trying to ask questions because I am not capable enough to answer them on my own. I will not be using this platform anymore, as a moderator you should not have treated a new member like that.
 

WBahn

Joined Mar 31, 2012
26,304
Okay, if you want to use microphones, then let's shift the discussion to using microphones (at least for now). The question still stands, what is the difference in the amplitude between the two sound waves supposed to tell you? Does it relate at all to the problem you are trying to solve (which still would seem to be the transmission of the output of two sensors to the same receiver)?

If you want to wear your feelings on your shirtsleeves, then there is nothing I nor anyone else can do to prevent you from behaving like an entitled little brat and sulking off and pouting. If, at some point, you decide you want to act like someone that wants to learn something, then make an attempt at moving your project forward as best you can (it doesn't have to be correct, but the attempt on your part needs to be there), ask questions about your proposed approach, and respond to feedback about that approach. The choice is entirely yours.
 

WBahn

Joined Mar 31, 2012
26,304
if the frequencies or the two transmitters are different then you filter one out, reverse the phase then mix it with the original signal. At the outout of the mix signal you can get one of the waves isolated and in the filter stage you can get the other. Or you can build 2 filters. Or if the phase of the two frequencies are different (offset your mic, form a right triangle instead of a equilateral triangle) the you can calculate the instantaneous amplitude and determine what signals has whatever value that you are trying to calculate. But one way or another, you got some work to do how ever you decide to do it? Just a word of advise calculating sonar and sound waves is normally harder the working with RF and electrical signals.
Let's say that you do all of that and successfully calculate the amplitude of one of the signals. What has that told you? Hint: Move the receiver and consider if you will still calculate the same amplitude. The amplitude information is only going to be useful if a number of things are carefully controlled and characterized. Frequency modulation is a lot better suited to this kind of stuff (though it is not without its challenges, to be sure). It would be helpful if the TS provided some basic information such as what kind of signal the sensors produce and what kind of fidelity to that output is needed at the receiver.

Also, how will forming a right triangle instead of an equilateral triangle necessarily accomplish anything. What if the right triangle is isosceles? Even if they are set up so that the two signals are in quadrature at the receiver, how is there any assurance that they will stay that way since they aren't synchronized (the description appears to imply that they are transmitting in the blind and, if nothing else, a solution that allows for that will potentially have a significant advantage over one that doesn't) then even a tiny mismatch in oscillators will result in them fading in and out of phase with each other.
 

crutschow

Joined Mar 14, 2008
25,670
I am sorry for causing confusions, I was planning to use leds but then I decided to use microphones. Thank you so much for your kind reply, I did not mean to make anyone do my project, I was simply trying to ask questions because I am not capable enough to answer them on my own. I will not be using this platform anymore, as a moderator you should not have treated a new member like that.
You stated you caused confusion and then are offended for the mild criticism of that.
If you feelings are that easily hurt then it would appear you need to find another field of endeavour where you will never receive any negative comments about any mistakes you make (and good luck with finding that). :rolleyes:
 

WBahn

Joined Mar 31, 2012
26,304
As for a right triangle the two output transducers will always be at different distances from the input transducer
But why will the output transducers always be at different distances from the input transducer?

The only thing I can think of is that you have one of the output transducers at the right angle. Is that what you have in mind? If so, that probably should be stated since a right triangle as ONE right angle and you have ONE input transducer, while it has TWO acute angles and you have TWO output transducers, so just saying that you are using a right triangle strongly implies that the input transducer is at the right angle of the triangle.

Even if we arrange them so, of course, does not mean that they will be at different phases at the receiver, even if the frequencies weren't subject to mismatch or drift. The wavelength of an 6800 Hz acoustic wave is about five cm (two inches), so pick any two vectors away from the receiver and place one of the transmitters randomly along one of them. Then put the other one randomly along the other (and they could even be the same vector). Now you only have to move one of them at most one inch either toward or away from the receiver in order to put both signals in phase.
 

WBahn

Joined Mar 31, 2012
26,304
My bad I was picturing the microphone at where points a,c or b,c intersect. But yes it could be the same distance in a right triangle where points a,b intersected. You know what??? Thank you.
I have no idea which points on the triangle you are labeling as 'a', 'b', and 'c'. I'm not a mind reader and my crystal ball is in the shop. One of them is almost certainly the vertex which is the right angle, but why make your readers guess which one? Redneckery might be all about guessing, but engineering is not. Nor do I know what it means for two points to intersect.
 

WBahn

Joined Mar 31, 2012
26,304
Ummm a,b,c are the basics in solutions of triangles and the Pythagoras theorem etc. I learned this when I was a child.....C, opposite the right angles C is the hypotenuse, b is side adjacent to angle a, a is the side adjacent to angle b.
In English textbooks, C is commonly the hypotenuse (with "point C" being the vertex opposite it, or the right angle), but that is far from universal. How you learned something as a child is not necessarily the convention used by everyone, particularly when discussing things on an international forum. There's little reason to assume that the textbooks in Turkey (where the TS is from) use the same labels in the same way as the textbook you used.

No I am not an engineer for a living but I sure can build and create whatever I want and can think up. I spend my time with electronics making synthesizers and modifying synthesizers, do you work on the things that you really want to or do you design for a living buck/boost converters and usb transceivers. Because that is why I didn't go to school for electrical engineering because I love electronics, and I didn't want to make a bunch of worthless crap I don't care about. I purchased the books and have done the homework and did not cut corners, Once again try not to think so highly of yourself. Any further response from me will be if the thread starter directly ask me a question.
Why do you keep trying to make this personal?

The notion that people that go to school for electrical engineering can only make worthless crap that they don't care about says far more about your attitude and misperceptions than it does about reality. To answer your question, I have designed many things over the years and all of them I cared about, whether it was an electronic radon level monitor or an imager that is presently in orbit about Mars.
 
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