grideye-driver

grideye-driver

Python driver for the Panasonic AMG88 Grid-EYE infrared array sensor.

Installation

The package is available on PyPI. Installation is can be done with your favourite package manager. For example:

pip install grideye-driver

Usage

In order to initialise the device we need an open SMBus object. Depending on the machine that you are running on you may need to provide another bus number or path:

from grideye import GridEye
from smbus2 import SMBus


with SMBus(1) as bus:
    device = GridEye(bus=bus)

The I2C address of the GridEye sensor is either 0x68 or 0x69. The default of the GridEye class is 0x69, and you can specify another address by providing for example GridEye(bus=bus, address=0x68).

Basic usage is as simple as:

with SMBus(1) as bus:
    with GridEye(bus=bus) as device:
        image = device.image

The image variable will be an 8x8 list-of-lists containing 64 floats - each representing the measured temperature in degrees Celsius of a pixel.

Device Mode

The device is instantiated in sleep mode. All functionality is unavailable in sleep mode - except for waking the device. The asleep property will be True.

The device can be woken with the wake()-method, and put back to sleep with the sleep()-method:

device = GridEye(bus=bus)
device.wake()
image = device.image
device.sleep()

Or instead, one can use the GridEye as context manager, which will automatically wake the device upon entering the context, and put it back to sleep when exiting the context - even in case of an error:

with GridEye(bus=bus) as device:
    image = device.image

or

device = GridEye(bus=bus)
with device:
    image = device.image

Settings

The Grid-EYE has two framerate settings: 1 fps or 10 fps. The framerate can be read and set with the frame_rate-property. The framerate value is always a grideye.FrameRate enum object:

device.frame_rate
>>> FrameRate.low   # Low is 1fps

It can be set by providing a FrameRate object:

from grideye import FrameRate
device.frame_rate = FrameRate.high

or by a string with value "low" or "high":

device.frame_rate = "low"

To reduce noise, the Grid-EYE has a moving average feature. It can be controlled by setting the moving_average-property or either True (enabled) or False (disabled).

Measurements

Two properties are available:

temp = device.device_temperature
image = device.image

The first returns the internal device temperature as a float, the latter an 8x8 matrix of sensor readings.

Interrupts

The Grid-EYE sports three types of interrupt: global, pixel-level and overflow.

The interrupts are configured with the interrupt_config-property, with is an InterruptConfig-object. This object has five attributes:

• An enabled-flag. If this is False, then the interrupt status flag is always True.
• Two limits: upper_limit and lower_limit.
• An absolute-flag. If this is False, then the upper and lower limit represent the minimum differences compared to the previous measurement to trigger the interrupt. Otherwise, the upper and lower values represent the absolute values below or above which the interrupt will be triggered.
• The hysteresis, which represents the hysteresis applied to the limits.

For example:

from grideye import InterruptConfig

device.interrupt_config = InterruptConfig(
    upper_limit=30,
    lower_limit=5,
    hysteresis=1,
    enabled=True,
    absolute=True
)

The interrupts can be easily disabled by calling device.disable_interrupts().

If any pixel breaches the limits as defined in the interrupt config, the interrupt-flag (device.interrupt) will be True. This can be reset to False by calling reset_interrupt.

Additionally, the interrupt status of each pixel is available as an 8x8 boolean matrix in device.pixel_interrupt. These values will not be changed by reset_interrupt: to clear those you will need to call reset_flags().

Finally, there is an overflow-property, which will be set to True if the internal ADC of the Grid-EYE has overflowed. This can be reset by calling reset_overflow(), or by calling reset_flags().

References

Panasonic product page