I want to have an alert that fires if the temperature as seen by my thermostat (T1800) drops a few degrees below the set point while the heat is on (This is to detect a failure in the furnace that the thermostat is controlling).

I can trigger on the zone temperature in relation to a constant; how can I compare the zone temperature to the set point? Or in general, how do I use more than one device state in a condition?

You can do it in an AppleScript condition or you want to use Python then use a python script action that tests the various conditions and if they are all met then execute some action group.

I have a lot of Applescripts setup to do this, but it would be nice to define conditions in the GUI per action rather than per trigger/schedule/action. Perhaps something to put on your exceptionally long wish list?

durosity wrote:I have a lot of Applescripts setup to do this, but it would be nice to define conditions in the GUI per action rather than per trigger/schedule/action. Perhaps something to put on your exceptionally long wish list?

Sure, we'll add it to the list.

In this particular example what I would do in this situation is probably create a Trigger action for whenever temperature value changes at all. Then for the action I would use a small embedded python script write the difference of the temperature and the setpoint to a variable value called _tempToSetpointDifference.

Then I could use that new value both on Control Pages and in the final trigger or conditional. That probably doesn't simplify the example much (some could argue it is more complicated), but it does help break down the logic into smaller pieces so you can use the UI for the final trigger/conditional logic.

I ended up doing it all in a Python action of a trigger, as Jay and Matt describe. Putting the difference into a variable is potentially interesting, but I also wanted to include the values in the email (which also sends me a text, since this is a relatively urgent condition):

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t = indigo.devices['Thermostat']
if (t.heatSetpoint - t.temperatures[0]) > 2:
  msgBody ="Check furnace - temperature (%d F) is more than 2 degrees below set point (%d F)"%(t.temperatures[0],t.heatSetpoint)
  indigo.server.sendEmailTo("nathanw@mydomain;9999999999@tmomail.net",
   subject = "Automation - house is cold",
   body = msgBody)
  indigo.server.log(msgBody)


The only annoyance I'm having now is that I want this to be conditional on the heat being enabled, but testing for that is more elaborate than I like:

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   "Any" "of the following rules are true"
      "If device" "Thermostat" "Mode is Heat (true or false)" "is true"
      "If device" "Thermostat" "Mode is Auto (true or false)" "is true"
      "If device" "Thermostat" "Mode is Program Heat (true or false)" "is true"
      "If device" "Thermostat" "Mode is Program Auto (true or false)" "is true"


Is there a good way to simplify that? I suppose I could encapsulate that logic in another trigger that exports a "heating is enabled" variable.