MLX90640 access library

This repository contains a simple access library for the MLX90640 FIR sensor manufactured by Melexis (this repository is in no way associated with the manufacturer). It uses a simple I2C wrapper to access the sensor and can be used on platforms like the RaspberryPi. Details are described in the accompanying blog article

Required I2C library

The I2C library is not contained in the requirements since it follows a modular approach. The modules author personally uses his own pyfbsdi2c-tspspi wrapper that can be installed using

pip install pyfbsdi2c-tspspi

This wrapper provides ioctl abstractions on FreeBSD and is mainly used on a RaspberryPi to talk to different I2C devices. Any other library exposing the pylabdevs I2CBus interface can be used to make this library as modular as possible.

Installation

pip install pymlx90640-tspspi

Usage

Fetch-Frame API

from fbsdi2c import FbsdI2C
from mlx90640 import MLX90640

import matplotlib.pyplot as plt
#import numpy as np

with FbsdI2C() as i2c:
    with MLX90640(i2c) as mlx:
        framedata = mlx.fetch_frame()

        fig, ax = plt.subplots(figsize=(6.4*2, 4.8*2))

        im = ax.imshow(framedata, cmap="plasma", interpolation="gaussian")
        ax.set_title("Temperatures")
        cbar = fig.colorbar(im, ax=ax, extend="both")
        cbar.minorticks_on()

        plt.show()

pysimplecam API

from fbsdi2c import FbsdI2C
from mlx90640 import MLX90640

import matplotlib.pyplot as plt

plt.ion()
fig, ax = plt.subplots()
axim = None

framectr = 0

def updateFrame(cam, frame):
    global axim, framectr, fig

    if axim is None:
        axim = ax.imshow(frame, cmap = "plasma", interpolation="gaussian")
    else:
        axim.set_data(frame)
        axim.autoscale()
    fig.canvas.flush_events()

    plt.savefig(f"simplecam01_cap/{framectr:08}.png")

    framectr = framectr + 1
    if framectr > 60:
        return False
    else:
        return True


with FbsdI2C() as i2c:
    with MLX90640(i2c) as mlx:
        mlx._set_refresh_rate(2)
        mlx.frameCallback = [ updateFrame ]
        mlx.stream()

tspspi / pymlx90640