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New Member
I wanted to make the pointer point to the direction of the transmitting source, so what i have decided to do is, make the motor rotate untill it recieves the highest signal strength. Obviously the highest signal strength will come from the actual direction of the source. So i connect a NOT gate to the output of the signal detector circuit so that the moment the detector circuit gats a "high" the motor goes "low" and stops. So suppose I move the transmitter a distance radially in a circle the motor starts turning since the detector becomes "low" and the motor becomes "high". This is only to find the direction of the transmitter when i turns around the reciever in 2 axes. Of course if the transmitter moves away from the reciever in the same axis the signal strength will become weak and the motor will start turning.

Now My problem is the detector circuit.
I need a circuit that will be able to detect the highest signal strength.
An FM reciever detector.
Please advise me on this.
Thank You Very Much


New Member
You cannot do this with Radio, you must find another solution. Radio is a little more complicated then you think, and poor topology would render your system useless. Remember, most fm antennas are omnidirectional..

Please take advice and move on to ultrasonics, sound, or infrared.. This approach would still offer a challenge, believe me :D
Mostly because the highs and lows are different with every sweep..

If I were to do this, I would probably use a fast 16-bit microcontroller (mps430), 16-bit-10bit ADC, and a high resolution absolute optical encoder or a high resolution stepper motor 400step/rev..

You would need to get a sample for each position from information from the encoder or from the stepper. The next part is tricky,, should someone compare each sample with the next sample? or should they gather all samples and process them? I suppose that the first solution would be best, but there would need to be an algorithm taking place. The second is easy, but there might not be enough processing time to keep up with the scanning.

This method would allow more flexibility rather then using comparators and etc., which wouldn't allow for change. For example, if the light or whatever is close, then the photoreceiver could be saturated over a large degree, giving no direction.

There are some things to think about :D


P.S. not gates and etc. are the least of your worries.. the process is more important


New Member
Thanks for the reply

Can you please expalin what a "high resolution" stepper motor and encoder is please?
Actually I thought of using voltage comparators for outputs that is why i thought that it might work with radio since varying singal strength vary teh voltage.
Actually Why would you need to do sampling and a high resolution encoder. I agree on the microcontoller part but I am not building a radar visual system. Please dont get me wrong as i am only introduced to this.
Please tell me what this high resolution encoder and stepper motor are.
And I agree that this is used only to find direction not proximity.
I am doing my 1st year in communications :oops: and I dont know about this new kind of stepper motor and optical encoder :oops: . So could you be kind enough to explain them to me or if possible to direct me to websites which explain these?
Thank You very much
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