Have you ever wanted to operate your Nest thermostat by using the Universal Devices’ ISY99i or ISY994i? If you have, you are looking in the right place!

This plugin and the instructions outlined below will enable your ISY99i to ISY994i to control the Nest thermostat by changing variables. These variable changes can be introduced in the ISY’s programs that you have already designed.

If you have an ISY program that runs while you are away from your house, you can add a “Set variable” in your program to set your Nest’s temperature to make sure you are earning your leaf! Like it colder at night while you are on your way to sleep? Insert a variable into your ISY’s program to set the temperature lower.

The possibilities are endless, limited only to your imagination.

Here are the instructions:

1. To start with, download EventGhost from http://eventghost.org
2. Next download the “Nest Thermostat” plugin for EventGhost from: http://www.eventghost.net/forum/viewtop … 080#p26481
3. Extract the ISYEvent.zip (from this link – ISYEvent) to your EventGhost program directory in the plugins folder. Make sure to use a special directory/folder for ISYEvent and the Nest plugin and to move both to their respective folders.
4. Open EventGhost for the first time and, delete most of the default tree, add and configure the ISY99i and Nest Plugin, and add the “Timer” plugin.
5. Open the ISY-Nest.xml file (from this link – ISY-Nest) to copy the contents to the clipboard. (Control-A, Control-C)
6. Reactivate the EventGhost window and click on any part of the tree. Press Control-V to paste the copied content from ISY-Nest.xml into a folder on Eventghost.
7. Make some new state variables on your ISY99i or ISY 994i for Set-Temp and Ambient-Temp, make note of the two variable numbers on the left side of the ISY variable panel.
8. Open up the “Read ISY Event” macro (gear icon) and double click on the Python script in that macro.
9. Alter ONLY THIS LINE: “if VarNum == “10”:” to reflect the proper digits of your Set-Temp variable that you created on your ISY. In my case it was 10. Click Ok.
10. Edit the Python script in the macro “Send Target Temp to ISY” called “Target Temp to ISY”
11. Edit “username:password@isy.ip.here” to your username/password for your ISY and the IP address.
12. Edit “set/2/10” to the number you have entered in the previous entry for “Set-Temp”. Click OK
13. Edit the Python Script in “Send Current Temp to ISY” called “Current Temp to ISY”
14. Edit “username:password@isy.ip.here” to your username/password for your ISY and the IP address.
15. Edit ” set/2/17/” to the number you have entered in the previous entry for “Ambient-Temp”, and click OK.

That’s it! Now you can start designing programs on your ISY to change your Nest’s temperature!

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