The voltage will depend on the specifics of the phone - they will not all be the same. That said, the voltage is likely in the 1-10V range.I want to know how much voltage is in a phone ear piece when someone send a text message to the phone and what is the best way to amplify or multiply it for other reasons.
Closing the door won't require a "voltage", it likely requires closing a contact like you do when you manually hit the button on the wall. So you need a way to activate a relay or such when the phone receives a text. It's possible. To avoid altering the phone at all, I recommend a circuit to "listen" for a tone. If you can use a specific ring tone, that would help because the circuit could filter out other noise and prevent that noise from opening the door unexpectedly.My plan is use skype to send a message to phone and use the message tone to build enough voltage to close garage door.
I'm not sure there is such a thing. Your carrier might send you a message or you might get a wrong number. I occasionally receive spam texts on my phone. Maybe your carrier can allow you can block all but certain numbers. Still, have you ever butt-dialed someone? I'd hate for my garage to open as a result!I am planning to use a dedicated account for text messaging where me and my wife only can send message to it.
My question is, why would you want to open your garage with a cell phone?I totally understand your concern. But my plan is to use a dedicated skype account which I allow who can send a message to. I have these local remotes. But I want one which I can use from physical remote/out a site location. This phone does not have service, it is on WiFi.
"Many" is right. Hacking garage doors seems to be a popular pastime.Here is one of many.