Set iPhone accelerometer to ±8g mode

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轮回少年
轮回少年 2021-02-05 03:09

Is it possible to set iPhone accelerometer to receive data in the ±8g range? (as far as I know ST LIS331DLH accelerometer installed on iPhone supports this mode)

We are

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  •  忘了有多久
    2021-02-05 03:55

    My "answer" doesn't contain direct answer to Evgeny's question. However I found a bunch of undocumented functions which probably can help.

    I have searched whithin iOS SDK for functions related to accelerometer. It seems like everything boils down to one of two frameworks (other frameworks rely on one of these): SpringBoardServices (Private) and CoreMotion.

    SpingBoardServices API is relatively simple: See also: SBSAccelerometer description

    objective-C API:

    @interface SBSAccelerometer : XXUnknownSuperclass {
        id _delegate;
        CFRunLoopSourceRef _accelerometerEventsSource;
        CFRunLoopRef _accelerometerEventsRunLoop;
        double _interval;
        NSLock* _lock;
        BOOL _orientationEventsEnabled;
        int _orientationEventsToken;
        NSThread* _orientationEventsThread;
        float _xThreshold;
        float _yThreshold;
        float _zThreshold;
    }
    @property(assign, nonatomic) id delegate;
    @property(assign, nonatomic) BOOL orientationEventsEnabled;
    @property(assign, nonatomic) float zThreshold;
    @property(assign, nonatomic) float yThreshold;
    @property(assign, nonatomic) float xThreshold;
    @property(assign, nonatomic) double updateInterval;
    @property(assign, nonatomic) BOOL accelerometerEventsEnabled;
    -(id)init;
    -(void)dealloc;
    -(void)_checkIn;
    -(void)_checkOut;
    -(void)_serverWasRestarted;
    -(int)currentDeviceOrientation;
    -(id)_orientationEventsThread;
    -(void)_orientationDidChange;
    @end 
    

    C-API (methods' signatures are unknown):

    int SBAccelerometer_server(struct unknown *in, struct unknown *out); //returns 1 on success, 0 otherwise
    int SBAccelerometer_server_routine(struct unknown *in); // retuns 0 on error;
    (?) SBSetAccelerometerClientEventsEnabled(...);
    (?) SBSetAccelerometerDeviceOrientationChangedEventsEnabled(...);
    (?) SBSetAccelerometerRawEventsInterval(...);
    (?) SBXXDeliverAccelerometerEvent(...);
    (NSString* or char*) _SBXXSBAccelerometer_subsystem;
    

    CoreMotion framework low-level API is C++ API. I won't publish all the API (it's much bigger than SpingBoardServices'), but there are most promising parts:

    CLSensorFusionAccelerometerOnly::reset(float)
    CLSensorNetworkProtocol::isAccelerometerPacket(__CFData const*)
    CLSensorNetworkProtocol::serializeAccelerometerPacket(CLAccelerometer::Sample const&)
    CLSensorNetworkProtocol::deserializeAccelerometerPacket(__CFData const*)
    CLSensorInterface::setAccelerometerCallbackAndInfo(void (*)(void*, CLMotionTypeVector3 const&, double const&), void*)
    

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