python/demos/get_laser_scan.ipynb

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    "# LiDAR の取得\n",
    "\n",
    "Matplotlib のインストールを行うコマンドが入っています。一度実行した後はこの処理はスキップ可能です。初回インストール後にkernelの再起動が必要です。"
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    "import math\n",
    "\n",
    "import kachaka_api\n",
    "import matplotlib.patches as patches\n",
    "import matplotlib.pyplot as plt\n",
    "from IPython.display import Image, clear_output\n",
    "\n",
    "client = kachaka_api.aio.KachakaApiClient()\n",
    "await client.set_manual_control_enabled(True)\n",
    "\n",
    "\n",
    "async def get_and_show_laser_scan_loop():\n",
    "    async for scan in client.ros_laser_scan.stream():\n",
    "        clear_output(wait=True)\n",
    "        fig = plt.figure(figsize=(5, 5))\n",
    "\n",
    "        n = len(scan.ranges)\n",
    "        x = list(range(n))\n",
    "        y = list(range(n))\n",
    "        for i in range(n):\n",
    "            theta = scan.angle_min + scan.angle_increment * i\n",
    "            x[i] = scan.ranges[i] * math.cos(theta)\n",
    "            y[i] = scan.ranges[i] * math.sin(theta)\n",
    "\n",
    "        plt.plot(0, 0, \"o\", color=\"black\")\n",
    "        plt.plot(x, y, \".\")\n",
    "        plt.xlim(-6.0, 6.0)\n",
    "        plt.ylim(-6.0, 6.0)\n",
    "        plt.grid(True)\n",
    "        plt.gca().set_aspect(\"equal\", adjustable=\"box\")\n",
    "        plt.show()\n",
    "\n",
    "\n",
    "await get_and_show_laser_scan_loop()"
   ]
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    "上記の方法は、手動操縦モードをONにすることでLiDARを動かしており、カチャカが動かずしばらく経つとスキャンが止まります。\n",
    "以下のようにActivatorを使うことで、カチャカが静止している状態でもスキャンを継続することができます。\n",
    "\n",
    "ただし**必要以上にスキャンを動かし続けると、LiDARの製品寿命を大幅に縮めることになります**ので、ご注意下さい。"
   ]
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   "cell_type": "code",
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   "source": [
    "from kachaka_api.util.vision import LaserScanActivator\n",
    "\n",
    "activator = LaserScanActivator()\n",
    "with activator.activate():\n",
    "    await get_and_show_laser_scan_loop()"
   ]
  }
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