Forums » Support

• Peter Childs

  

  • 5 posts
   

  January 20, 2016 12:27 AM CET

  So awesome.  Many thanks.

• Tamás Fábián

  

  • 178 posts
   

  January 19, 2016 3:52 PM CET

  ...the wiki page was also updated. Check it out!

• Tamás Fábián

  

  • 178 posts
   

  January 19, 2016 3:08 PM CET

  Hello Peter,

  Convert LE bytes to integer (C/JAVA): int adc = (((int)low) & 0xff) + ((((int)hi) & 0xff) * 256) Where "low" is the byte at the lower memory address, and hi is the byte at the higher memory address.

   

  Voltage is calculated as: (double)adc / 16.0 * 1.22 / 2047.0 * 11.0;

   

  Temperature is calculated as: (double)adc / 145.0067 * 1.22 - 160.0;

• Peter Childs

  

  • 5 posts
   

  January 19, 2016 4:11 AM CET

  This is driving me nuts :)

  In Scan Response -- 06 00 00 04 00 04 08 04 01 00 f0 45 07 02 b8 8b 6b 4c 99 b4 02 03 00

   

  Via ADC measurement ==> fc 45

   

  I assume the spec 'little endian' msb means

   

  ((( 0x45 & 0x0f ) << 8 ) | 0xfc ) / 16 * ( 1240/2047 ) == > 58.001954079140205

   

  Help Help?

   
• Peter Childs

  

  • 5 posts
   

  January 14, 2016 4:45 AM CET

  With reference

    https://social.sbrick.com/wiki/view/pageId/11/slug/the-sbrick-ble-protocol

  0F Query ADC
  
  I send 0F00 and read into 2 byte buffer values
   0x30 0x48
  
   So dec 48 and 72 -> 48 + ( 72 * 256 ) => 18480

  Document notes 
    The PSU voltage is dropped through a 10:1 voltage divider.
    VPSU = ADC / 16 * 1.24 / 2047 
  
   = 18480 / 16 * 1.24 / 2047
   = 0.6996 
  
  This value looks wrong.
  
  Measuring with multimeter I get 7.46v .. sbrick iphone app gives 7.43v 
  
  Help?  Am I doing something incorrectly ?
  
  

  
  This post was edited by Peter Childs at January 14, 2016 4:45 AM CET