MLX90640热成像传感器

MLX90640 热成像模块

MLX90640 是一款高分辨率红外热成像传感器，可与 Raspberry Pi 配合使用，实现实时温度可视化。通过 Python 脚本读取数据并显示热图，调整刷新率和插值优化图像。

3D渲染效果

硬件连接

MLX90640	RaspberryPi	Note
SDA	SDA (Pin3)	Serial Data
SCL	SCL (Pin5)	Serial Clock
GND	GND	Ground
VIN	3V3	Power

示意图

实物图

环境搭建

创建并激活虚拟环境

python -m venv .venv
source .venv/bin/activate

安装所需软件包

pip install numpy
pip install matplotlib
pip install RPi.GPIO adafruit-blinka
pip install adafruit-circuitpython-mlx90640

连接测试

终端执行指令

sudo i2cdetect -y 1

显示 iic 设备地址为 0x33 对应设备为 MLX90640

通信测试

终端执行 mlx90640_print_temp.py 新建文件并添加如下代码

import time
import board
import busio
import numpy as np
import adafruit_mlx90640

def main():
    # Setup I2C connection
    i2c = busio.I2C(board.SCL, board.SDA, frequency=400000)
    mlx = adafruit_mlx90640.MLX90640(i2c)
    mlx.refresh_rate = adafruit_mlx90640.RefreshRate.REFRESH_2_HZ

    frame = np.zeros((24 * 32,))  # Initialize the array for all 768 temperature readings

    while True:
        try:
            mlx.getFrame(frame)  # Capture frame from MLX90640
            average_temp_c = np.mean(frame)
            average_temp_f = (average_temp_c * 9.0 / 5.0) + 32.0
            print(f"Average MLX90640 Temperature: {average_temp_c:.1f}C ({average_temp_f:.1f}F)")
            time.sleep(0.5)  # Adjust this value based on how frequently you want updates

        except ValueError as e:
            print(f"Failed to read temperature, retrying. Error: {str(e)}")
            time.sleep(0.5)  # Wait a bit before retrying to avoid flooding with requests
        except KeyboardInterrupt:
            print("Exiting...")
            break
        except Exception as e:
            print(f"An unexpected error occurred: {str(e)}")

if __name__ == "__main__":
    main()

保存代码。

效果

终端执行指令 python mlx90640_print.py 运行代码

终端打印采集画面的平均温度，手掌靠近传感器，温度上升至体温。

图像显示

终端执行 touch mlx90640_plt.py 新建文件，添加如下代码

import time
import board
import busio
import numpy as np
import adafruit_mlx90640
import matplotlib.pyplot as plt

i2c = busio.I2C(board.SCL, board.SDA)
mlx = adafruit_mlx90640.MLX90640(i2c)
mlx.refresh_rate = adafruit_mlx90640.RefreshRate.REFRESH_4_HZ  # Set to a feasible refresh rate

plt.ion()
fig, ax = plt.subplots(figsize=(12, 7))
therm1 = ax.imshow(np.zeros((24, 32)), vmin=0, vmax=60)
cbar = fig.colorbar(therm1)
cbar.set_label(r'Temperature [$^{\circ}$C]', fontsize=14)

frame = np.zeros((24*32,))
t_array = []
max_retries = 5

while True:
    t1 = time.monotonic()
    retry_count = 0
    while retry_count &lt; max_retries:
        try:
            mlx.getFrame(frame)
            data_array = np.reshape(frame, (24, 32))
            therm1.set_data(np.fliplr(data_array))
            therm1.set_clim(vmin=np.min(data_array), vmax=np.max(data_array))
            fig.canvas.draw()  # Redraw the figure to update the plot and colorbar
            fig.canvas.flush_events()
            plt.pause(0.001)
            t_array.append(time.monotonic() - t1)
            print('Sample Rate: {0:2.1f}fps'.format(len(t_array)/np.sum(t_array)))
            break
        except ValueError:
            retry_count += 1
        except RuntimeError as e:
            retry_count += 1
            if retry_count &gt;= max_retries:
                print(f"Failed after {max_retries} retries with error: {e}")
                break

保存代码。

效果

终端执行指令 python mlx90640_plt.py 运行代码；

弹窗显示 matplotlib 伪彩图，调整摄像头位置，动态采集热成像画面；

优化平滑

为了优化画面显示效果，使用 Matplotlib 内置函数对数据进行平滑处理。

终端执行 touch mlx90640_plt_smooth.py 新建文件，添加如下代码

import time
import board
import busio
import numpy as np
import adafruit_mlx90640
import matplotlib.pyplot as plt

def initialize_sensor():
    i2c = busio.I2C(board.SCL, board.SDA)
    mlx = adafruit_mlx90640.MLX90640(i2c)
    mlx.refresh_rate = adafruit_mlx90640.RefreshRate.REFRESH_4_HZ
    return mlx

def setup_plot():
    plt.ion()
    fig, ax = plt.subplots(figsize=(12, 7))
    therm1 = ax.imshow(np.zeros((24, 32)), vmin=0, vmax=60, cmap='inferno', interpolation='bilinear')
    cbar = fig.colorbar(therm1)
    cbar.set_label(r'Temperature [°C]', fontsize=14)
    plt.title('Thermal Image')
    return fig, ax, therm1

def update_display(fig, ax, therm1, data_array):
    therm1.set_data(np.fliplr(data_array))
    therm1.set_clim(vmin=np.min(data_array), vmax=np.max(data_array))
    ax.draw_artist(ax.patch)
    ax.draw_artist(therm1)
    fig.canvas.draw()
    fig.canvas.flush_events()

def main():
    mlx = initialize_sensor()
    fig, ax, therm1 = setup_plot()
    
    frame = np.zeros((24*32,))
    t_array = []
    max_retries = 5

    while True:
        t1 = time.monotonic()
        retry_count = 0
        while retry_count &lt; max_retries:
            try:
                mlx.getFrame(frame)
                data_array = np.reshape(frame, (24, 32))
                update_display(fig, ax, therm1, data_array)
                plt.pause(0.001)
                t_array.append(time.monotonic() - t1)
                print('Sample Rate: {0:2.1f}fps'.format(len(t_array) / np.sum(t_array)))
                break
            except ValueError:
                retry_count += 1
            except RuntimeError as e:
                retry_count += 1
                if retry_count &gt;= max_retries:
                    print(f"Failed after {max_retries} retries with error: {e}")
                    break

if __name__ == '__main__':
    main()