title: Understanding BLE characteristic values for cycle power measurement 0x2A63
body: <p>I am currently using Dart/Flutter BLE plugin to better understand BLE devices.</p>
  
  <p><strong>Plugin:</strong></p>
  
  <p><a href="https://pub.dartlang.org/packages/flutter_blue" rel="nofollow noreferrer">https://pub.dartlang.org/packages/flutter_blue</a></p>
  
  <p>When I connect to my virtual cycle trainer I select the 0x1818 service and then I subscribe to the 0x2A63 characteristic for Cycle Power Measurement.</p>
  
  <p>I am struggling to align the response list I get with the GATT documentation for this service/characteristics below. There is 18 values in this list, however there is only 17 in the GATTS list. Also the values don't seem to make any sense.</p>
  
  <p>I also tried to convert the first two values '52','24' to a 16 bit binary to see if that aligns with the flags for the first field, but the result was the below which again makes no sense.</p>
  
  <pre><code>0x3418 = 11010000011000
  </code></pre>
  
  <p><a href="https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.characteristic.cycling_power_measurement.xml" rel="nofollow noreferrer">https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.characteristic.cycling_power_measurement.xml</a></p>
  
  <p><strong>This screenshot is when I first connect to the trainer.</strong></p>
  
  <p><a href="https://i.stack.imgur.com/OeAkT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OeAkT.png" alt="enter image description here"></a></p>
  
  <p><strong>This screenshot is when I am cycling lightly on the bike</strong></p>
  
  <p><a href="https://i.stack.imgur.com/SGurY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SGurY.png" alt="enter image description here"></a></p>
  
  <p><strong>This screenshot is when I stop cycling but the pedals and wheel are still turning.</strong></p>
  
  <p><a href="https://i.stack.imgur.com/1ZZFQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1ZZFQ.png" alt="enter image description here"></a></p>
  
  <p>The cycle trainer is the Cycleops Magnus, which doesn't have the Cycle Speed Cadence service 1816, but can provide virtual speed based on power.</p>
  
  <blockquote>
    <p>My Question is this:</p>
    
    <p>Which of the values in the list corresponding with the GATTS
    characteristics and bonus question is, how would I infer speed or
    cadence from the values in this service?</p>
  </blockquote>