Cell phone Signals --> LED

JeanneFRIES's picture

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Cell phone Signals --> LED
June 29, 2017 - 7:07am

Building a simple circuit to pick up 3G and 4G cell phone signals and trigger LED's

 

This is not about gettting the INFORMATION of the signal, simply showing when there is a phone or phones reciving or sending texts and calls

I dont need a buzzer - just the LED part. any suggestions, what i have tried so far is not working.

https://circuitdigest.com/electronic-circuits/cell-phone-detector-circuit 

 

Thanks

Aswinth Raj's picture

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That circuit should have
June 29, 2017 - 11:45am

That circuit should have worked for you purpose. You can simply remove the buzzer if you do not need the sound. 

This circuit is very much sensitive with the values of components. So make sure you have used the right values of capacitors and resistors. What problem are you getting?

JeanneFRIES's picture

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I believe that the RF shown
June 29, 2017 - 5:10pm

I believe that the RF shown in this video are lower than the ones i need to pick up in North America. Do you know how they got the value of the capacitors? and how it can be adjusted to pick up 1900-2200 mhz frequencies? I have been thinking maybe ill atatch https://www.adafruit.com/product/1991 into the circut??

 

How would I do this?

 

 

JeanneFRIES's picture

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Well I am waiting on one or
June 29, 2017 - 5:06pm

Well I am waiting on one or two pieces. However, I think that the radio frequency used in this video, is not as high as they are in North america. Do you know how they got the value of the resistors? 

How can I adjust the parts to be suited for 1900-2200 Mhz?

 

 

Aswinth Raj's picture

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The circuit is for 900-1800 Mhz
June 30, 2017 - 2:19pm

Hi Jeanne,

Yes you are right the circuit that you shared was for 900-1800 Mhz. Make sure if your countries band is different from that by checking out this link below

http://www.worldtimezone.com/gsm.html

If you are sure that your band is 1900-22000 Mhz you have vary the time constant of resistor R1 and R2 and C1 and C2. 

To make it work practically, you can replace the 100K (R2)  with a pot and try chaning the resistor to know at which range it picks up your mobile frequency.

 

 

JeanneFRIES's picture

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Thats wonderful!
July 1, 2017 - 5:01pm

Thats wonderful!

How do I adjust the capacitors in relation to the resistors? Is there a formula or general rule? 

 

I really apprecitate your help!