A Thing is the all encompassing name for sensors and actuators. They are addressable with an id, and can measure more than one type of measurement (called a metric). Important here is that a Thing can in fact be a single hardware device (with one id) that has multiple sensor-heads. This means it can for instance measure gps, air humidity and temperature at the same time (all different metrics).
Sensors and actuators are typically made by several different companies, all speak different protocols. A lot of sensors aren't even developed to be deployed in the field, but rather in a home network, so they have no real means to communicate outside that home LAN.
This is where DYAMAND comes in. DYAMAND allows us to abstract everything down to a generic sensor or actuator that sends understandable messages to the Obelisk cloud backend.
For more straightforward integrations, the platform HTTP Ingest API can be used as is, see the section on Sending values.