pynq.iop.grove_light — Python productivity for Zynq (Pynq) v1.0

# Source code for pynq.iop.grove_light

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    __author__      = "Yun Rock Qu"
    __copyright__   = "Copyright 2016, Xilinx"
    __email__       = "pynq_support@xilinx.com"

    from time import sleep
    from math import log
    from pynq.iop import Grove_ADC
    from pynq.iop import iop_const
    from pynq.iop import PMODA
    from pynq.iop import PMODB
    from pynq.iop import ARDUINO

    class Grove_Light(Grove_ADC):
        """This class controls the grove light sensor.

        This class inherits from the Grove_ADC class. To use this module, grove
        ADC has to be used as a bridge. The light sensor incorporates a Light
        Dependent Resistor (LDR) GL5528. Hardware version: v1.1.

        Attributes
        ----------
        iop : _IOP
            I/O processor instance used by Grove ADC.
        mmio : MMIO
            Memory-mapped I/O instance to read and write instructions and data.
        log_running : int
            The state of the log (0: stopped, 1: started).
        log_interval_ms : int
            Time in milliseconds between sampled reads of the Grove ADC sensor.

        """
        def __init__(self, if_id, gr_pin):
            """Return a new instance of an Grove ADC object.

            Parameters
            ----------
            if_id : int
                IOP ID (1, 2, 3) corresponding to (PMODA, PMODB, ARDUINO).
            gr_pin: list
                A group of pins on stickit connector or arduino shield.

            """
            if not if_id in [PMODA, PMODB, ARDUINO]:
                raise ValueError("No such IOP for grove device.")

            super().__init__(if_id, gr_pin)

        def read(self):
            """Read the light sensor resistance in from the light sensor.

            This method overrides the definition in Grove_ADC.

            Parameters
            ----------
            None

            Returns
            -------
            float
                The light reading in terms of the sensor resistance.

            """
            val = super().read_raw()
            return self._int2R(val)

        def start_log(self):
            """Start recording the light sensor resistance in a log.

            This method will call the start_log_raw() in the parent class.

            Parameters
            ----------
            None

            Returns
            -------
            None

            """
            super().start_log_raw()

        def get_log(self):
            """Return list of logged light sensor resistances.

            Parameters
            ----------
            None

            Returns
            -------
            list
                List of valid light sensor resistances.

            """
            r_log = super().get_log_raw()

            for i in range(len(r_log)):
                r_log[i] = self._int2R(r_log[i])
            return r_log

        def stop_log(self):
            """Stop recording light values in a log.

            This method will call the stop_log_raw() in the parent class.

            Parameters
            ----------
            None

            Returns
            -------
            None

            """
            super().stop_log_raw()

        def _int2R(self, val):
            """Convert the integer value to the light sensor resistance.

            This method should only be used internally.

            Note
            ----
            A smaller returned value indicates a higher brightness. Resistance
            value ranges from 5.0 (brightest) to 35.0 (darkest).

            Parameters
            ----------
            val : int
                The raw data read from grove ADC.

            Returns
            -------
            float
                The light sensor resistance indicating the light intensity.

            """
            R_sensor = (4095.0 - val) * 10 / val
            return float("{0:.2f}".format(R_sensor))