Is there anyway to read data from an attachment through the USB port on an Android device? In particular, an EKG. Most the work can be done by the hardware of the device to simplify the output to a single number, a voltage reading. If its not possible, what about modifying an accessory that can already communicate with an android device? Thinking of devices that attach to android phones, what about sending the data as an audio signal to be read as the microphone from a headset and then analyzing the audio signal to convert it to a number that can be used to display a value.

Any ideas on how to make this work?