Unable to decode weight machine value when bluetooth weight scale in KG mode in flutter-CodePudding

My weight scale has two modes:

when the device is in-lb(pound mode) the decode output response is correct

DEVICE OUTPUT :[3, 52, 18, 224, 7, 2, 25, 3, 49, 28]

EXPECTED VALUE: 46.6lb

ACTUAL VALUE : 46.6lb

When DEVICE IS IN LB MODE the output is CORRECT using below code

double getWeight(List<int> data, index) {. return (( 0xff & data[index 1] ) << 8 | ( 0xff & data[index] ) << 0 ) / 100; }

Refer below link for the above code details: Flutter ble read weight scale characteristic value

But When the device unit is KG MODE, the decode output response is wrong

DEVICE OUTPUT :[2, 168, 12, 224, 7, 2, 25, 3, 51, 7]

EXPECTED VALUE: 46.7 lb

MY DECODED VALUE:32.4 lb

Consume please guide to decode it proper way for this issue?

CodePudding user response：

If you look for "3.244 Weight Scale Measurement" in the following document: https://www.bluetooth.com/specifications/specs/gatt-specification-supplement-6/

It says about the weight field:

This field is in kilograms with resolution 0.005 if the bit 0 of the Flag field is 0 or in pounds with a resolution of 0.01 if the bit 0 of the Flag field is 1.

So if the flag suggests you are in KG then you function is:

double getKgWeight(List<int> data, index) {
  return (( 0xff & data[index   1] ) << 8 | ( 0xff & data[index] ) << 0 ) * 0.005;
}

For lbs:

double getlbsWeight(List<int> data, index) {
  return (( 0xff & data[index   1] ) << 8 | ( 0xff & data[index] ) << 0 ) * 0.01;
}