Hi!
I just took apart my Nokia 6060 and removed the speaker that plays melody when a call is being received. Then i soldered two wires to the same place where the speaker was. I set the call alert to BEEP ONCE and measured the voltage coming from those wires (during incoming call). I got max 0.1 Volts in 1 or 2 second then goes back to 0 Volts.
How can i use this to turn on led that is connected to Arduino Duemilanove? Do i have to use relay or can i somehow use those wires directly so that when Arduino gets 0.1V (short impulse) from input, it turns on output led?? Any ideas?
I measured that voltage using cheap digital multimeter with DC function and range 20. Before, with the same settings, i measured voltage from AA battery and it showed 1.33 Volts.
Did some tests...
Today I got it working (at least I think so). I measured the voltage (of beep-once ringtone) - it is not pulsating anymore but the capacitor charges up to 2.89 Volts and starts to empty.
I still want to connect it to Arduino board, that should recognize the voltage 2.89 (from ANALOG IN) and then do sumthing like Digital Pin HIGH.
Also I noticed funny thing when i added some RESISTORS after the capacitor and diode, the voltage goes still 2.89 and sometimes even over 3.20 volts.. i thought that resistors limit the voltage but at the moment they don't do that
Does anyone have any idea how should i code the arduino to recognize the voltage coming from my cellphone ?
Also i would like to know if i may feed ca. 3 VOLTS to Arduino's ANALOG IN ?
I was thinking about using "knock sensor tutorial"
int ledPin = 13;
int knockSensor = 0;
byte val = 0;
int statePin = LOW;
int THRESHOLD = 100;
void setup() {
pinMode(ledPin, OUTPUT);
beginSerial(9600);
}
void loop() {
val = analogRead(knockSensor);
if (val >= THRESHOLD) {
statePin = !statePin;
digitalWrite(ledPin, statePin);
printString("Knock!");
printByte(10);
printByte(13);
}
delay(100); // we have to make a delay to avoid overloading the serial port
}
Somehow i managed to get it work (using Knock Sensor Code), but after some time it just stopped working... at first i thought that i've burnt my Duemilanove... but the computer recognizes it and i can upload new sketches... dont know what happened. Maybe just the capacitor or diode got broken
So if you measure the voltage from a battery, and then put a 1K (or so) resistor in line between the battery and the meter you will still read the same voltage. It is only when resistors have current flowing through them do they have voltage dropped across them.
Maybe just the capacitor or diode got broken
It is unlikely, it is more likely something became disconnected. Put in a print statement after the reading to see what values you are getting. This might have changed.
Thanks for Your reply!
I got it working, but did some changes -
i use optocoupler ( led + LDR ) to get the signal out of cellphone. Using the same knock sensor script. All working fine - when i call to the phone that is connected to arduino, a led turns on and when i call second time to that phone, leds turns off. I have some remote controllable wall-adaptors that im planning to use with my arduino project. So that when i call to arduino, for example a lamp or radio or tv turns on. Also it is possible to make a door lock that can be opened by calling to it.
