Bug in Heart Rate example

Question

Hi, 
 there seems to be a bug in the Heart Rate Monitor (HRM) example or in the iOS app (nRF connect) -- when the simulated heart rate exceeds 8 bits (256) in the example, the corresponding iOS app starts showing incorrect values (259 instead of 260, 269 instead of 270, and so on). So, either the encoding part in the nordic SDK is broken, or the decoding part in the app. Any ideas?

Audience · Answer

Alright, I found the bug. It's in the iOS app which incorrectly converts the 2 bytes from the heart rate. My code in Swift 4.2 is now -- I'll leave it to the maintainer of nRF connect to fix it in their example which uses Objective-C: 
 private func heartRate(from characteristic: CBCharacteristic) -> Int { guard let characteristicData = characteristic.value else { return -1 } let array = characteristicData.toArray(type: UInt8.self) var bpmValue : Int = 0; if ((array[0] & 0x01) == 0) { // Stored in one byte bpmValue = Int(array[1]) } else { //Stored in two bytes bpmValue = (Int(array[2]) << 8) + Int(array[1]) } return bpmValue }

Bug in Heart Rate example

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