Phone calls indicator

[George221]

anyone know how to make a LED blinks when someone calls? i'm trying to add a LED to my phone as a indicator.

like when the phone rings it sends signal to the transistor then turn on the LED!?

[jwatte]

Are you using a regular, wired, landline phone, or a wirelss/cell phone?
Landline phones ring signals are driven by a voltage pulse. You can detect that pulse with an appropriate Zener diode, and tie that detection to a blinking circuit.
Cell phones do not typically have a standard signal that tells you someone's calling, although you could maybe get that information out of the Bluetooth interface if it's supported. (This is approximately 100,000 times more complicated than the landline version!)

[Admin]

Depending on the phone you have, you could connect a wire to the phone's speaker or vibrating motor and use it as a signal to activate your circuit.

There are a dozen ways you can do this. Depends on the features and level of complexity you are aiming for.

(note: this is how terrorists use cell phones to trigger bombs )

[George221]

Depending on the phone you have, you could connect a wire to the phone's speaker or vibrating motor and use it as a signal to activate your circuit.

There are a dozen ways you can do this. Depends on the features and level of complexity you are aiming for.

(note: this is how terrorists use cell phones to trigger bombs )

im trying to make a iPhone case with led in it, and active when calls receives.
and i want to apply the concept of mobile calling  blink accessories which the accessory attach to the phone and blinks when someone calls.
ex (

iPHONE4 4S來電閃燈殼

)

[Admin]

Several ideas come to mind . . .

A sound sensor or a vibration sensor that activates the LED when someone calls.

Or maybe plugging into the headphone jack, and detecting a signal when someone calls.

Or, assuming the iPhone has a status LED on it that changes when receiving a call, to use a photoresistor to detect a call and activate your LED circuit.

You'd have to spend time googling around for how best to do it.

[jwatte]

As far as I know, mobile call sensors just sense significant radio power nearby in the general cell phone spectrum. They don't even distinguish the particular carrier frequency. The reason this works is that power falls off as one over r squared, so there'll be close to a watt available close to the phone, even thugh there are only milli- or micro-watts available at the cell phone tower. Also, cell phones just a few feet away will be relatively significantly weaker.

[George221]

As far as I know, mobile call sensors just sense significant radio power nearby in the general cell phone spectrum. They don't even distinguish the particular carrier frequency. The reason this works is that power falls off as one over r squared, so there'll be close to a watt available close to the phone, even thugh there are only milli- or micro-watts available at the cell phone tower. Also, cell phones just a few feet away will be relatively significantly weaker.

how to build that kind of circuit? what do you need