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mbl_mw_acc_set_odr not working

aleph00aleph00
in iOS

Hello! I want my app to change the device's data collecting frequency. Below is my code.

func accelerometerStartLog(device: MetaWear) {
        mbl_mw_acc_set_odr(device.board, 2.0)
        mbl_mw_acc_bosch_write_acceleration_config(device.board)

        guard let signal = mbl_mw_acc_bosch_get_acceleration_data_signal(metaWearDevice!.board) else {
            print("Error: Acceleration signal not given")
            return
        }

        mbl_mw_datasignal_log(signal, bridge(obj: self)) { (context, logger) in
            if let _ = logger {
                print("logger ready\n");
            }
            let _self: DeviceViewController = bridge(ptr: context!)
            let cString = mbl_mw_logger_generate_identifier(logger)!
            let identifier = String(cString: cString)
            let intBitPattern = Int(bitPattern: logger!)
            _self.loggers[identifier] = intBitPattern
            _self.logger = logger
        }

        mbl_mw_logging_start(metaWearDevice!.board, 0)
        mbl_mw_acc_bosch_enable_acceleration_sampling(metaWearDevice!.board)
        mbl_mw_acc_start(metaWearDevice!.board)
    }

However, it seems that the line mbl_mw_acc_set_odr(device.board, 2.0) is not working. I think I am mistaken about a few functions. Can someone tell me what's wrong? Thank you.

Comments

  • LauraLaura

    Your code looks fine, it would set the ODR to 1.5625Hz (the closest value to 2.0). What makes you think it isn't working?

  • aleph00aleph00
    edited September 2021

    @Laura
    When I tested the code through streaming, the data was collected too frequently. mbl_mw_acc_set_odr(device.board, 2.0) doesn't seem to work.
    Below is my test code.

    func accelerometerStartLog(device: MetaWear) {
        mbl_mw_acc_set_odr(device.board, 2.0)
        mbl_mw_acc_bosch_write_acceleration_config(device.board)
    // datasignal_subscribe for testing
        mbl_mw_datasignal_subscribe(signal, bridge(obj: self)) { (context, data) in
            let obj: MblMwCartesianFloat = data!.pointee.valueAs()
            print("\(obj)\n")
        }

        guard let signal = mbl_mw_acc_bosch_get_acceleration_data_signal(metaWearDevice!.board) else {
            print("Error: Acceleration signal not given")
            return
        }
        mbl_mw_datasignal_log(signal, bridge(obj: self)) { (context, logger) in
            if let _ = logger {
                print("logger ready\n");
            }
            let _self: DeviceViewController = bridge(ptr: context!)

            let cString = mbl_mw_logger_generate_identifier(logger)!
            let identifier = String(cString: cString)
            let intBitPattern = Int(bitPattern: logger!)   
            _self.loggers[identifier] = intBitPattern
            _self.logger = logger
        }

        mbl_mw_logging_start(metaWearDevice!.board, 0)
        mbl_mw_acc_bosch_enable_acceleration_sampling(metaWearDevice!.board)
        mbl_mw_acc_start(metaWearDevice!.board)
        metaWearDevice!.flashLED(color: .blue, intensity: 1.0, _repeat: 3)

    }
  • LauraLaura

    Your code looks fine. Do you have data to show why you think this isn't working?

  • aleph00aleph00

    @Laura
    According to the file, acceleration data is collected every 80ms. Even though I set it to 2Hz, I think the MMS accelerometer is set to 12.5Hz.

  • LauraLaura

    This has been fixed in the new cpp lib update: https://github.com/mbientlab/MetaWear-SDK-Cpp/releases

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