问题
I'm currently dealing with a new project and I have to send data through headphone jack with specific voltage, then i can work on that voltage.
so here i need to program the specific voltage depends on my data. is it possible that i can access the output voltage of headphones in android and then create a application to control that voltage?
回答1:
Here is a HackADay article dealing with this issue. http://hackaday.com/2010/02/01/android-audio-serial-connection/ It offers working code which was quite a bit simpler than I thought it would be.
Although, like others have suggested, including this very similar SO post, you might have an easier time using the USB port.
回答2:
the simplest way to catch input data from audio jack in android or iphone is through recording http://developer.android.com/reference/android/media/AudioRecord.html
think something similar like playing a linear pcm audio file , I have n't tried but I believe it should work
回答3:
I believe you will have to dive deep into Assembly type language, however, why the headphone jack? As I understand it, only reverberations and sound are transmittable through the headphone jack. I believe it would be more feasiable to output voltage through the Mini-USB port.
I think this site may be of some help regarding my method:
http://pinouts.ru/Slots/USB_pinout.shtml
回答4:
you could maybe try turning your data into binary for example when your listening to music your head phone jack changes +- vibrating to make a sound so you could make +- = 0 and -+ = 1
来源：https://stackoverflow.com/questions/10248649/sending-data-through-headphone-jack-in-android-phones