サーマルカメラ(サーモ AI デバイス TiD) Python VL53L0X編

Pololu Time-of-Flight 距離センサモジュール VL53L0Xの距離データを、I2C通信で取得します。

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1. 紹介編
2. センサ編
3. センサケース編
4. Raspberry Pi編
5. Python編
   5.1 Form編
   5.2 オムロン 非接触温度センサ D6T-44L-06編
   5.3 Pololu 測距センサ VL53L0X編
   5.4 BOSCH 温湿度・気圧センサ BME280
   5.5 シャットダウン・再起動スイッチ編
   5.6 OpenCV編
   5.7 高速化編
   

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Raspberry Pi上のPythonでVL53L0Xからデータを取得する為に、adafruit-circuitpython-vl53l0xモジュールを使用します。
adafruit-circuitpython-vl53l0xモジュールがインストールされていない場合、下記コマンドでインストールしてください。

sudo pip3 install adafruit-circuitpython-vl53l0x

vl53l0x.pyはパッケージとしてimportして使用しますが、テスト用に単体で距離データを取得できます。
vl53l0x.py (ZIPで圧縮済)

#!/usr/bin/env python
# -*- coding:utf-8 -*-
"""
MH VL53L0X script.
==================
"""
import threading
import time

i2c_enable = False
try:
    import adafruit_vl53l0x
    import board
    import busio
    i2c_enable = True
except:
    i2c_enable = False
import numpy as np
import random


class VL53L0X():
    def __init__(self, *args, **kwargs):
        """
        mesure length: 30 - 2000[mm]
        Optionally adjust the measurement timing budget to change speed and accuracy.
        See the example here for more details:
          https://github.com/pololu/vl53l0x-arduino/blob/master/examples/Single/Single.ino
        For example a higher speed but less accurate timing budget of 20ms:
        vl53.measurement_timing_budget = 20000
            Or a slower but more accurate timing budget of 200ms:
        vl53.measurement_timing_budget = 200000
        The default timing budget is 33ms, a good compromise of speed and accuracy.
        ***
        avg: Average counts.
        range: Default is (30, 2000).
        in_range: If distance is inth range then True.
        """
        self.i2c_enable = i2c_enable

        self._distance = 0
        self._history = []
        self._shutdowning = False
        self._in_range = False

        self._avg = 1
        self.avg = kwargs.get('avg', self._avg)

        self._range = (30, 2000)
        self.range = kwargs.get('range', self._range)

        self.vl53 = None
        if self.i2c_enable:
            i2c = busio.I2C(board.SCL, board.SDA)
            try:
                self.vl53 = adafruit_vl53l0x.VL53L0X(i2c)
            except:
                self.i2c_enable = False

        self._processing()

    def __call__(self, *args, **kwargs):
        return self.distance

    @property
    def avg(self):
        return self._avg
    @avg.setter
    def avg(self, value):
        self._avg = value
        self._history = [0]
        for _ in range(self.avg - 1):
            self._history.append(0)

    def __del__(self):
        self._shutdowning = True

    @property
    def distance(self):
        return self._distance

    @property
    def in_range(self):
        return self._in_range

    def _processing(self):
        if self._shutdowning:
            return

        tmp = 0
        if self.i2c_enable:
            # For I2C error at pushed power switch.
            try:
                tmp = self.vl53.range
            except:
                pass
        else:
            # This value is for D6T-44L-06.
            tmp = random.randint(500, 550)

        if tmp <= 2000:
            self._history[1: self.avg] = self._history[0: self.avg - 1]
            self._history[0] = tmp

        self._distance = np.average(self._history)

        if (self._distance >= self._range[0]) \
                & (self._distance <= self._range[1]):
            self._in_range = True
        else:
            self._in_range = False

        time.sleep(0.1)

        thread = threading.Thread(
            name='VL53L0X_Measuring',
            target=self._processing,
        )
        thread.daeom = True
        thread.start()

    @property
    def range(self):
        return self._range
    @range.setter
    def range(self, value):
        self._range = value

    def stop(self):
        self._shutdowning = True


if __name__ == '__main__':
    vl = VL53L0X(avg=10)
    while True:
        print(f'Range: {vl()}[mm] {vl.in_range}')
        time.sleep(0.1)
    pass

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