Digital Dash Documentation, Part 7: Incoming Phone Commands

When the digital dash system starts up, it makes a Bluetooth tethering connection to my phone.  There is a Tasker profile on the phone that listens for this connection to be made, and when it sees it, it runs a startup task of its own.  The details of that will be covered in a later part of the documentation, but the only thing we're interested in now is the fact that part of that sequence launches a low-priority looping task that repeats about every three minutes.

What that task does is to read the current ambient temperature from the phone's sensor (via Tasker's built-in %TEMP variable) convert it to Fahrenheit, append the degree symbol, and send it off to the tablet via an AutoRemote message.


Profile: V3_IncomingCommands (368)
State: AutoRemote [ Configuration:All Messages ]
State: Variable Value [ %V3_DrivingMode Set ]
Enter: V3_HandlePhoneCommands (369)

This profile, running on the tablet, simply listens for any incoming AutoRemote message.  When it sees one, it fires off it's entry task.  Since I'm really only sending one message, I'm not making use of any of AutoRemote's filtering capabilities; I just look for any message and let the entry task figure out what to do with it.

A1: Variable Set [ Name:%V3_CurrentTemp To:%arpar() Do Maths:Off Append:Off ] If [ %arcomm ~ Temp ]

When it comes in, the AutoRemote message looks like this: "the temperature"=:=Temp (Where "the temperature" is the current ambient temperature, including the degree symbol.)  In AutoRemote terms, anything to the left of the =:=  is called the parameter(s) and is contained in the %arpar() local variable.  LIkewise, anything to the right of the symbol string is called the command and is found in the %arcomm local variable.  All this task does is check to make sure that this is a "TEMP" command and, if it is, sets the %V3_CurrentTemp global variable equal to the parameter payload.  %V3_CurrentTemp is used as the source for the temperature text element on the V3_RH scene shown on the main display. 

Although I'm only sending one type of message at this time, the system is easily expandable if I want to add additional types.