Auto-off after X minutes standby for Wemo Insight switches

I got this idea after noticing that, even while spending the majority of its time on standby, my home theater was going to cost me ~$13/mo at home.

I know that the Wemo Insight keeps track of how long the connected load is "in standby" and thought it would be great if I could turn off the switch after a certain amount of time on standby to save some more money. Turns out I'm not alone in this idea.

Well, we know IFTTT is a great resource for automating your Wemo devices, but unfortunately they don't provide such a trigger/action. So, it's time to build one!

Step 1 - Set up the required IFTTT services

Step 1.1 - Wemo Insight

Click here and follow the steps to connect IFTTT to your Wemo account.

Step 1.2 - Maker Webhooks

Click here and follow the steps to enable Maker connectivity.

Make note of the URL IFTTT provides. It should look something liked this: https://maker.ifttt.com/trigger/{event}/with/key/<key here> - save this for later.

Step 2 - Sign up for a free Azure cloud account

Click here to get started with a free account. The cool thing to note about what I've implemented is that it will very likely continue to be free for as long as you use it due to the pricing nature of Azure Functions. (Check out how one very popular website runs on mere pennies/day here)

Note: In order to sign up you'll have to have a Microsoft account. If you use outlook/hotmail/live.com you've already got one of these. You can create one with any e-mail address, though!

Step 3 - Click this 'Deploy to Azure' button

This will take the resources I've created in this repo and push them out to your new Azure account. These are what do the meat of the work required for implementing the "wait for X minutes" logic we're missing in IFTTT using Azure Functions and Azure Durable Functions.

This creates the "shell" in to which you'll be deploying code (in just one moment).

Note: If you don't want to automatically get the updates that I push, you need to fork the repo and point to your own copy of it, putting the URL to the repo and branch you want to use in the deployment form then pull in updates as you see fit and deploy them to your fork. By default you will pull updates from this repo's master branch.

Step 4 - Get the URL to your new Function

When the above is finished

1. Click the 'Manage' links that shows up:

2. Click the item that has the the lightning bolt next to it and the name you put in to 'Site Name' in the deploy step:

You should see a set of Functions shown, like this:

Click on the StandbyAutoOff one, then choose Get function URL:

Then click 'Copy':

Put this somewhere safe, you'll need it later.

Step 5 - Connect IFTTT to Azure when your Wemo comes out of Standby

This is required due to the following scenario

• Wemo goes in to standby, you have timeout set to 20 minutes
• Wemo comes back out of standby at minute 5

You don't want the Wemo to shut off 15 minutes later. So we need to fire an event when the Wemo comes back out of standby as well.

5.1 - Create a new IFTTT Applet on your Insight switch

Create a new IFTTT Applet for your Insight switch, to be triggered when your switch turns on. To do this you use the Switched on trigger:

Choose the switch you want to monitor and click Create trigger.

For the +that portion, choose search for Webhook and choose the Webhooks recipe:

then the Make a web request action:

• URL: The function URL you copied earlier
• Method: POST
• Content-Type: application/json
• Body: { "wemoId": "<unique name, NO SPACES>", "standbyEntered": false }

Example body: { "wemoId": "downstairstv", "standbyEntered": false }

This tells our Azure Function that the device came out of standby, and it should stop the countdown to shutoff.

Step 6 - Wire up IFTTT to shut off your Wemo switch when the Azure Function calls out to it

For this we use a Webhook trigger instead of action. Create a new Applet and search for webhook then choose Webhooks and then the Receive a web request action

Give it a unique event name - something specific to the switch you'll be turning off - without spaces (e.g. turnoff_downstairstv) and click Create trigger.

For the +that portion, configure shutting off the target Wemo Insight switch:

Step 7 - Connect IFTTT to Azure when your Wemo goes in to Standby

Repeat Step 5 above except choose Standby mode entered as the trigger

and for the Body of the webhook, make it look like this:

{
	"wemoId": "downstairstv",
	"standbyEntered": true,
	"timeoutDurationMinutes": 120,
	"callbackUrl": "https://maker.ifttt.com/trigger/<step 6 event name>/with/key/<key in URL from Step 1.2>"
}

where callbackUrl is the address you stored off from Step 1.2, configured with the event name you gave in Step 6. It should look something like this: https://maker.ifttt.com/trigger/turnoff_downstairstv/with/key/asdfqwefbadrty

Important: The wemoId property in this body must match the one you used for Step 5.

You can change the amount of time you wait to shut off the device by tweaking the value of timeoutDurationMinutes.

How it works

The meat of the logic here is, obviously in the Azure Function. For the configuration here, the algorithm is as follows:

• When I get a request, check to see if I'm already wired up to listen for wemoId
  • If not, create a new listener for wemoId and let it know the value for standbyEntered
  • If so, just let it know the value that came in for standbyEntered
• When I get an alert on a new standbyEntered value
  • If it is true, start a timer, or ignore it if a timer is already going.
  • If it is false, the device turned back on so stop the timer and wait for another standbyEntered event later
• If I hit the timeout that was given to me for the first standbyEntered = true alert for this wemoId, send a message to the callbackUrl.

Important: As highlighted, you can only set the timeout for a given Wemo switch once: the first time it's used. I hope to modify this solution in the future to accept changes to the timeout.

For IFTTT's part, we call the function with standbyEntered = true when the device goes in to standby, which starts (or restarts) the timer. Similarly, we call it with standbyEntered = false when the device turns on (comes out of standby).

Important considerations

The alerts here revolve entirely around the configuration of your Wemo Insight switch. Most importantly the On/Standby Threshold setting. If you have this mis-configured, a few things are possible:

1. The Wemo will never trip as going in to Standby (your threshold is too low)
2. The Wemo will never trip as turning on (your threshold is too high)
3. The Wemo will oscillate constantly between On and Standby, overloading IFTTT and your Azure Function (your threshold is right on the edge and needs to be higher)

If you encounter any of these problems, have a look at your threshold setting.

When you initially set this up, I recommend you have the IFTTT Applets set to send you notifications when they're triggered until you've got things going the way you want. This is a great way to ensure things are set up properly.