/sensortile

a simple intro to get data from ST sensortile (using BLE)

sensortile

sensortile is a multi-sensor device, giving us many physical data such as acceleration, temprature, etc. you can find out more about sensortile on official website. there is also an example application (android/ios) for recieving and monitoring sensortile data. the android SDK and example app source code are available on github: here!

while trying to use sensortile to catch some physical data (on a platform that's not android) i found out there is no datasheet or GATT table for using sensortile BLE; however there is some standard rules. i will attach a sample python script (uses bluepy) so you will see the raw data.

here is the GATT table:

characteristics:

Feature Handle UUID
ProximityGesture::Motion Intensity 0x000d 00140000-0001-11e1-ac36-0002a5d5c51b
FeatureAcceleration::FeatureGyroscope::FeatureMagnetometer 0x0010 00e00000-0001-11e1-ac36-0002a5d5c51b
FeatureAccelerationEvent 0x0013 00000400-0001-11e1-ac36-0002a5d5c51b
FeatureMicLevel 0x0016 04000000-0001-11e1-ac36-0002a5d5c51b
FeatureMemsSensorFusionCompact 0x0019 00000100-0001-11e1-ac36-0002a5d5c51b
FeatureCompass 0x001c 00000040-0001-11e1-ac36-0002a5d5c51b
FeatureActivity 0x001f 00000010-0001-11e1-ac36-0002a5d5c51b
FeatureCarryPosition 0x0022 00000008-0001-11e1-ac36-0002a5d5c51b
FeatureMemsGesture 0x0025 00000002-0001-11e1-ac36-0002a5d5c51b
FeatureAudioADPCM 0x0028 08000000-0001-11e1-ac36-0002a5d5c51b
FeatureAudioADPCMSync 0x002b 40000000-0001-11e1-ac36-0002a5d5c51b

each characteristic contains 3 description. you must write value 0x0100 to first description of each char (this is a standard method). then sensortile will send you data continuously as notification. you could enable multiple notifications at the same time. notifications will arrive as characteristic value. so you can distinguish notifications.

  • note
    • for two first chars, data has following patern: 2byte 2byte 2byte ... 2byte there is some more info about data structure and uuid prefixes at SDK git page
  • note
    • each char data has a time stamp at two first bytes, except stream data (audio)
  • note
    • audio formatting is ADPCM. you cannot find any library to dicode this format to PCM(WAV) (except a corrupt python lib!). so you have two ways: write decode yourself! or use sox library.

    //end