The Myo armband is great little wireless sensor package which includes built-in recognition for 5 default gestures and access to raw EMG and IMU data.
The raw EMG and IMU data can be accessed via the Myo SDK or Bluetooth protocol. We have a great tutorial on the Myo Developer Blog that will help you get started in addition to the sample apps included with the Myo SDK.
For reference, the EMG data is streamed at 200Hz and the IMU data is streamed at 50Hz. The EMG data is returned as a unitless uint_8 for each sensor representing "activation" and does not translate to volts (V) or millivolts (mV).
Currently only the Windows, Mac and iOS SDKs have access to raw EMG data. We do not have a timeline for when the Android SDK will receive access.