Need Help with Cell Phone detector circuit

[petraj02]

I am trying to modify this circuit to detect when my cell phone is receiving an incoming call. I am having trouble figuring out howo the sensor coil will work in this circuit. I also am going to incorporate a band stop filter to use 5kHz as my trial frequency. Can someone help me to understand this????

R1-100K 1/4W Resistor
R2-3K9 1/4W Resistor
R3_1M 1/4W Resistor

C1,C2_100nF 63V Polyester Capacitors
C3_220µF 25V Electrolytic Capacitor

D1_LED Red 10mm. Ultra-bright (see Notes)
D2_1N5819 40V 1A Schottky-barrier Diode (see Notes)

Q1_BC547 45V 100mA NPN Transistor

IC1_7555 or TS555CN CMos Timer IC

L1_Sensor coil (see Notes)

B1_1.5V Battery (AA or AAA cell etc.)

 

[audioguru]

When the cell phone receives a call, it transmits back to the cell phone office that it is turned on and has received the call. It transmits very high frequency RF, not 5kHz.
The coil picks up the RF and the transistor amplifies it and triggers the Cmos 555 monostable.

 

[petraj02]

So... I really was having a hard time with the sensor coil and decided to just replace it with an AC input. I used 3kHz as my trial frequency, meaning that I am just trying to figure out if I can get this circuit to work. I am adding a band pass filter to only allow the 3kHz signal as my input frequency.
Thank you

 

[audioguru]

Why do you want to use an audio-high-frequency bandpass filter?
Doesn't your cell phone activate the circuit when it rings? They must be very close together because the coil and transistor are not sensitive. If they were more sensitive then the circuit would be activated by local TV stations.

 

[petraj02]

Ok so when the cell phone will ring the coil will produce the RF and therefore....????? I am confused !!

 

[audioguru]

When the cell phone rings it transmits data back to the cell office that it is receiving a call. If the coil is close to the cell phone then it picks up the radio transmission and the transistor amplifies it. Then the collector of the transistor triggers the Cmos 555 monostable.

Does your circuit work? Or not?

 

[petraj02]

I am having a problem to simulate it, I am not getting the correct output! So correct me if I am wrong the sensor coil just acts as a receiver for my circuit because I am getting so confused!

 

[audioguru]

Why bother simulating it? The simulation software doesn't know how it is supposed to work. Just make the very simple circuit.