Add an LED to a Phone.

Hi everyone,

I have a Siemens Euroset 5005 phone at work. Unfortunatly the lowest setting for volume is still too high. So I was wondering, it would be a nice project to take it apart and add an LED that lights up / blinks when someone calls.

How was i thinking of doing this?

take hte phone apart, check where the speaker is. Solder a wire to the speaker (+) and send it to a transistor.

|----- 3v coin battery ----| | | speaker----- (Transistor) | | | |--------- LED ------------|

When the phone rings, sends a small pulse to the transistor, and the transistor connects the LED to the 3v battery.

Since I'm not a big expert with this, before drilling a hole in the phone i'd like to hear some opinions =)

I might need a tip on which transistor to choose. Maybe a 2n2222? Should be pretty standard.

If this works, maybe i'll add an LED and a small vibrating motor. Just in case i dont see the light, ill feel the phone vibrating. ;)

Why not simply fit a resistor in series with the speaker to reduce its volume.

I would have thought that inserting a resistor in line with the speaker would be sufficient to reduce its volume.

When the phone rings, sends a small pulse to the transistor,

The only problem with this is that the speaker voltage would have to be greater than 0.7V in order to turn on the transistor. If it is greater than this how about replacing the speaker with the LED, then you would not have to have the coin cell. There is sufficient voltage going into the phone so that you will not need a battery.

Just a note, if you are in the UK any DIY modification to a phone is illegal, because then the phone will not have "type approval" and it is illegal to connect any device without "type approval" to the telephone line.

@Grumpy_Mike I'm not living in the UK. should be an harmless mod o_o

Hmmm true, I could lower the volume with a resistor. Maybe i'll do that AND add a visual alert (LED). Also, i could replace the speaker with the LED but i'd lose the ringing for good. The phone lets me mute the ring, so i can just mute it and use the LED.

Gotta meter the voltage to the speaker, if its greater than 0.7v, my idea should work :D

Later tonight ill be modding it ;) Thank you.

P.S: (hmmmmmm.... if i mute the ring, the speaker wont get any voltage, and LED wont flash if the speaker is muted.... crap. Guess the resistor AND the LED would be the best choice.)

fantastic, it worked just fine!

even easier than i thought. When ringing the speakers as a voltage of +- 10V. I added 1 resistor and 3 LED's in series, parallel to the speaker, and i have Sound and Light alerts for the call ;D

After that i muted the phone and the LED's still blink, even if the speaker isn't doing any sound. yay, worked just fine ;)

PIC: http://dl.dropbox.com/u/1739057/Photo%20on%202011-11-18%20at%2000.46.jpg

ill try and take a picture of it working tomorrow morning ;)