I'm trying to create a JSON serializer in Play 2.3.4 and line #7 give a compiler error saying "No Json deserializer found for type Array[models.Sensor]. Try to implement an implicit Reads or Format for this type." Given there is a default serializer for Array, I assume this should work.

SiteApi.scala

  case class CreateParams(name: String, interval: Int, camera: Boolean, sensors: IndexedSeq[Sensor])
  implicit val createParamsReads = new Reads[CreateParams] {
    def reads(js: JsValue): JsResult[CreateParams] = {
      val name = (js \ "name").as[String]
      val interval = (js \ "interval").as[Int]
      val camera = (js \ "camera").as[Boolean]
      val sensors = (js \ "sensors").as[IndexedSeq[Sensor]]
      JsSuccess(CreateParams(name, interval, camera, sensors))
    }
  }

  implicit val sensorReads = new Reads[Sensor] {
    def reads(js: JsValue): JsResult[Sensor] = {
      val name = (js \ "name").as[String]
      val unit = (js \ "unit").asOpt[String]
      val scale = (js \ "scale").as[Double]
      val offset = (js \ "offset").as[Double]
      val internal = (js \ "internal").as[Boolean]
      JsSuccess(Sensor(name, unit, scale, offset, internal))
    }
  }

Ooops.... wrong order.