Hi! Today I will show you how to use Blynk and IFTTT.
First of all, you need a project on blynk with a button to control for example an LED or a Relay.
Then download IFTTT from Google Play Store (https://goo.gl/snr4DQ) or from Apple Store (https://goo.gl/FXz1f2)
Now open IFTTT, go to "My Applets" and tap on add on top right corner, click on "this" and then find "Google Assistant" after that choose a trigger and complete all phrases on trigger chosen, click on the tick on the right corner, and now select "that", find "Webhooks", "make a web request" and now, in the URL you need to put "http://YOUR_COUNTRY_BLYNK_IP/YOUR_TOKEN_HERE/pin/D7 (D7 = digital 7, change it to turn on or off the pin you want) to find the blynk IP from your country just go to command line on PC and write: ping cloud.blynk.cc. For my country (Portugal) the IP is 126.96.36.199, then the link will look like http://188.8.131.52/545db7988exxxxxda8bae2506b99bc25/pin/D7
after you have your link paste it into URL on IFTTT, choose the method to "PUT", the "Content Type" to "application/json" and the body you put ["0"] to turn ON (if it is an relay). Now to turn off you need to make all the steps before, only changing the body to ["1"].
Now save all, call your assistant and ask her for the phrase you choose, after that the pin you choose will turn ON or OFF.
Here you can view the screenshots (http://imgur.com/a/hQBrQ)
And feel free to contact me if you have any problems
You don't need to choose Google Assistant, you can for example choose a button widget, or sms... Think out of the box!
(sorry for my basic english ;_;)