How to convert data to double with more than one character ? [swift]

Asked Jun 10 '19 at 18:58

Active Jun 10 '19 at 19:03

Viewed 87 times

I am trying to convert data from my Arduino bluetooth device to a Double. So I write this function :

 func convert(from characteristic: CBCharacteristic) -> Double {

    guard let arduinoData = characteristic.value else { return -1 }
    let byteArray = [UInt8](arduinoData)

//  print(characteristicData as NSData)

    return Double(byteArray[0])
}

I receive character ascii from my arduino. So this code works for numbers from 0 to 9. But I want to receive value like 300.207

I would like to know if it was possible to read 7 octets in succession to place them in a single double ?

I try with the code bellow to read the first octet and the seconde but I have this error : Thread 1 : Fatal error: Index out of range

func convert(from characteristic: CBCharacteristic) -> Double {
        guard let arduinoData = characteristic.value else { return -1 }
        let byteArray = [UInt8](arduinoData)

        return Double(byteArray[0]) + Double(byteArray[1])
    }

Thanks ( I am a beginner )

edited Jun 10 '19 at 19:03

asked Jun 10 '19 at 18:58

H.U

Possible duplicate of https://stackoverflow.com/questions/31773367/convert-byte-array-to-double-in-swift ? – jake Jun 10 '19 at 19:10
In what format is the value sent? Show the output of `print(arduinoData as NSData)` . – Martin R Jun 10 '19 at 19:35
I receive this : <01> Mmhg: 49 mmhg <34> Mmhg: 52 mmhg – H.U Jun 10 '19 at 19:43
jake I have already seen his posts. But I have trouble understanding the proposed solutions – H.U Jun 10 '19 at 19:46
Take a look at this aswer. Great explanation how to do that. https://stackoverflow.com/a/38024025/2243451 – Marius Kažemėkaitis Jul 23 '19 at 05:05

How to convert data to double with more than one character ? [swift]

0 Answers0