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How can I approximate the distance between an RF receiver and its transmitter? Keep in mind I want to have some method of encoding as well. I only need distance not direction.Would I have the transmitter send a packet and then have the RF receiver adjust its gain until it gets the correct packet , and based on that gain I get an estimated distance.
The only way to do RF rangefinding is do time of flight, and there is a reason why time of flight rangefinders are so expensive.
Then how do these things work :
Those "Keep-Your-Luggage" gizmos all works by relative field strength, usually by measuring the AGC-voltage.
Quote from: Soeren on November 27, 2008, 04:07:05 PMThose "Keep-Your-Luggage" gizmos all works by relative field strength, usually by measuring the AGC-voltage.How can I get the AGC voltage from this module - http://www.sparkfun.com/commerce/product_info.php?products_id=8948
Would I have the transmitter send a packet and then have the RF receiver adjust its gain until it gets the correct packet , and based on that gain I get an estimated distance
So I would do the method I said in my first post , right?
alternatively if you cannot adjust your module's gain just count the % of successful transmissions at a set power level.
you would be better looking for a module with a signal strength output pin on the RX module.
Is there some linear equation or some relationship between number of successful packets and approximate distance?
Can you provide me with a link and an approximate price? Can I modify the Sparkfun RF module to provide a signal strength output pin?
Which one of the following methods would work :1. Count how many successful RF transmissions are received per second - that means there is a linear relationship between successful transmission and distance.2. Adjust the auto-gain of the RF receiver until you get correct RF transmissions - means there is a linear relationship between gain value and distance3. Somehow get a signal strength output pin on the RF module - any one know which RF module can do that?
Is there a better way to do it?
P.S. Its kind of urgent that I get this question answered by the end of today
My problem is that I cannot find any module that provides me with signal strength
Google yielded these results :http://www.zen22142.zen.co.uk/Circuits/rf/sfsm.htmhttp://www.electro-tech-online.com/electronic-projects/58-simple-field-strength-meter.htmlIt seems like I can change around the inductor and capacitor setting for my application.
The only thing I could think of is to design a circuit at the antenna pins to read the signal strength, but I really do not have any details on that.
Any ideas on what kind of circuit that would be?|