how do i add a speed attribute to my app, i want to report things like speed, and engine state(idle or moving)
Traccar already has those attributes by itself; it depends more on the device and its configuration to determine its speed and status. For example, Sinotrack has a gyroscope, and when it reports, it sends its speed and also indicates its status, whether it's operating on battery or with power. In contrast, Coban only shows more basic information
Speed is a basic parameter that doesn't require any computed attributes. Why do you think you need computed attributes in the first place?
im very confused as to how to use the computed attributes in my traccar app, i just want the device to report attributes like speed, state of vehicle whether idle, parked or moving. can anyone explain me please how does this computed attribute thing work