Harsh V

Blink LED using FM radio

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I am trying to modify an FM radio such that it blinks an LED according to the data I transmit from my FM transmitter.


I am following the circuit attached below.


Is it possible to connect LED to speaker terminals to obtain such result? or any other suggestions?




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Many circuits on that website are wrong, especially this one that might NOT be an FM radio. Its transistors are connected with positive feedback that might cause them to oscillate and cause radio interference to a REAL FM radio. Or T2 is saturated and T1 is cutoff and they stay like that. Maybe the transistors are a weird regenerative receiver?


If you connect an LED to the output terminals of a power amplifier like the LM386 then its very high output current will blow up the LED in an instant if the supply voltage is high enough for the LM386 to make the LED light up. An LED must have a current-limiting resistor or circuit in series.


How are you transmitting data on an FM transmitter? Data is ones and zeros. Are the ones loud sounds and the zeros are no sounds? Or are you using audio-frequency shift keying when ones are a high pitched tone and zeros are a low pitched tone? 

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