In #8 we agreed that sensors shouldn't be singletons because it was both useful to allow multiple instances of each sensor and necessary to support multiple sensor of a given type on a single device (think for example proximity sensors on a car).

Imagine we want to check the presence of an object on the back of a car, we'll need to get data from one of the back sensors, right?

Should we go with a generic system, taking a DOMString, that would be defined in this spec, so for example:

new Sensor.Proximity({ identifier: "back-right" });
new Sensor.Temperature({ identifier: "internal" });

…or should we let specs for concrete sensors implement that the way they want? So we might get something like (trading off consistency for context):

new Sensor.Proximity({ position: "back-right" });
new Sensor.Temperature({ id: "internal" });

Questions:

• Is such an identifier the right solution?
• Should we favor consistency or context?
• What happens when no identifier is passed to the constructor? Must there be a default sensor for each type so that you can do: new Sensor.Geoloc() and not new Sensor.Geoloc({ identifier: "default" })?
• Where are those lists of sensors defined? In the concrete specs themselves? Through an API the consumer can query (e.g. Sensor.Proximity.getAll())?