{
  "description":"measure distance",
  "spec": {
    "id": "__HOPE__/demo/tank/distance/measure",
    "in": {
      "ports": [{
        "name": "trigger"
        }]
    },
    "out": {
      "ports": [{
        "name": "distance",
        "type": "number"
      }]
    }
  }
}