watchOS2 - CMSensorRecorder

Question

I want to use the historical accelerometer data from the Apple Watch and my accDataList is always nil. I instantiated CMSensorRecorder in the init function of the class. Does someone had this problem before?

func startMovementDetection(){
    self.cmSensorRecorder?.recordAccelerometerFor(self.recorderDuration)
    self.startDate = NSDate()
}

func extractHistoricalAccelerometerData(){
    var accDataList = self.cmSensorRecorder!.accelerometerDataFrom(self.startDate, to: NSDate())
    NSLog("AccDataList : \(accDataList)")
    if accDataList != nil {
        accDataList = accDataList as CMSensorDataList
        for accData in accDataList {
            self.addHistoricalAccDataToMovementArray((accData as? CMRecordedAccelerometerData)?.acceleration)
        }
        self.sendDataToIphone()
    }        
}

Log looks like this:

2015-07-11 22:02:55.279 emmoveDataWatchOS Extension[2158:2428612] Start recording

2015-07-11 22:02:55.279 emmoveDataWatchOS Extension[2158:2428612] AW: Start Motion Updates

2015-07-11 22:02:55.279 emmoveDataWatchOS Extension[2158:2428612] AW EMWatchManager: startMovementDetection

2015-07-11 22:02:55.279 emmoveDataWatchOS Extension[2158:2428612] Optional(CMSensorRecorder: 0x797733d0)

2015-07-11 22:10:51.483 emmoveDataWatchOS Extension[2158:2428612] AW: Stop Motion Updates

2015-07-11 22:10:51.484 emmoveDataWatchOS Extension[2158:2428612] Extract Data from Optional(2015-07-11 20:02:55 +0000) to 2015-07-11 20:10:51 +0000

2015-07-11 22:10:51.484 emmoveDataWatchOS Extension[2158:2428612] Optional(CMSensorRecorder: 0x797733d0)

2015-07-11 22:10:51.486 emmoveDataWatchOS Extension[2158:2428612] AccDataList : nil

How long are you waiting between calling record and polling for the data? I've found that the data only available a few minutes after recording has started. — Redoubts, Jul 06 '15 at 15:55
Okay, i tested it with appr. 4 min. I will try it with a longer gap. — Narsail, Jul 06 '15 at 21:19

score 0 · Accepted Answer · edited May 23 '17 at 11:59

0

Maybe you can try to

func startMovementDetection(){
    self.startDate = NSDate()
    self.cmSensorRecorder?.recordAccelerometerFor(self.recorderDuration)
}

And have a look at Swift watchOS 2 - CMSensorDataList

edited May 23 '17 at 11:59

Community

1
1

answered Aug 17 '15 at 17:28

Marcus Vinicius Kuquert

480
4
5

Eventually with the new Xcode and iOS betas the function works now. Thanks for your help! – Narsail Sep 04 '15 at 08:38

score 0 · Answer 2 · answered May 14 '16 at 14:49

0

the CMSensorRecorder also have a bug: you should wait for 3 to 5 minutes to restart your Recorder, otherwise the List will always return nil.(you can watch the Apple's video for more details.)

answered May 14 '16 at 14:49

Cassie Xia

45
8

score 0 · Answer 3 · answered May 31 '16 at 06:59

I had the same problem, found the solution in this post:

https://forums.developer.apple.com/thread/15470

"It apparently does not like the charger to be plugged in on the watch when starting recroding"

Just need to disconnect the device from its charger. Makes sense, but of course not documented officially anywhere...

score 0 · Answer 4 · answered Jul 25 '20 at 17:22

Make sure that Settings > Privacy > Motion & Fitness > Fitness Tracking is enabled.

If it's disabled, CMSensorRecorder.accelerometerData() always seems to return nil even though

CMSensorRecorder.isAccelerometerRecordingAvailable() == true

and

CMSensorRecorder.authorizationStatus() == .authorized

watchOS2 - CMSensorRecorder

4 Answers4

Linked