{
  "description":"detect whether on the black line",
  "spec": {
    "id": "__HOPE__/demo/makeblock/follower/detect",
    "in": {
      "ports": [{
        "name": "trigger"
        }]
    },
    "out": {
      "ports": [{
          "name": "value",
          "type": "int"
        }]
    },
    "config": [
      {
        "name": "pin",
        "type": "int",
        "required": true
      }
    ]

  }
}