I have been playing around with sensors on Android for the last few days, and I turns out there’s a bunch of undocumented sensors, mostly from QTI (seems to be part of Qualcomm). It seems that at some point that is suppose to be in an SDK, but now that SDK is discontinued, and I can’t seem to find anything that can tell me exactly what they are suppose to do. That’s why I have been toying with all those sensors, and this is what I have figured out so far, and if you have information of the missing pieces, or have more undocumented sensors, comments down below!

1. Facing (type=33171002): values[0] = facing up(1.0f) or down(2.0f)
2. Basic Gesture (type=33171000): values[0] = push(1.0f), pull(2.0f), shake left(3.0f), shake right(4.0f), shake up(5.0), or shake down(6.0)
3. Absolute Motion Detection (type=33171006): values[0] = moving (2.0f) or stationary (1.0f)
4. Tile detector (type=22): values[0] = 1 when a tilt motion has been detected (i.e. you pick up the phone with it’s corner). Not very accurate IMO

These are the 3 sensors that I can figure out. Here’s the rest of the sensors that I still don’t (fully) understand what they represent:

1. Relative Motion Detection(type=33171007): I don’t have a car and I don’t really know how to actually test this right now.
2. Pedometer(type=33171009): It spits out so many data! It returns 16 float every single freaking time! Right now I guess values[0] represents total steps, but it is not increasing incrementally, that’s why I am not certain about it.
3. Motion Acceleration(type=33171011): I think the difference between this and just normal Acceleration is that it only reports when motion is actually being detected, but I haven’t cross check it with ACCELEROMETER just yet.
4. Coarse Motion Classifier(type=33171012): This is definitely the most interesting one: according to this blog, it is suppose to be able to distinguish between 7 activities, 7 HUMAN ACTIVITIES. Basically this is the the Activity Recognition API, but without Google Play Services! It spits out values between 1 and 7 when I am trying it out, but since I am very tied to the computer (which is tied to the desk), I cannot say for certain what those numbers represents. Right now I think 0 or 1 represents resting or sitting, while 6 or 7 represents walking or running. Again, I don’t have a car, so I cannot test the other scenarios.