IoT OTG for Alexa

Allows you to control your home using Raspberry Pi's and Google Assistant, Siri, or Alexa by texting from 1 accepted number. When using Alexa you need an AT&T account which is the only phone service provider I know of at this time that allows you to text with Alexa through their texting skill.

Install this app on a Android phone, go to application manager and allow it to interact with received texts.

Then open app, go to settings and enter what phone numbers you will allow this app to take actions from. Then go to settings and add a device (name, ip address, gpio pin number).
Then on the phone you have added to allow to control your Raspberry Pi's create a contact with a name easy to remember (Jarvis) and assign the phone number of the phone with this app installed.

Once you have the contact created through AT&T's Alexa skill app you can say:
Alexa, Text Jarvis
"What would you like to say to Jarvis?"
Turn on basement
"Ok, sending Jarvis, Turn on basement"

basement light comes on.

phone will tell you it received message
phone will tell you if message was from an accepted number
phone will tell you if it is turning on or off a device

Also works with Siri from an iPhone texting to an Android phone with this app.

(All of this can be done on the same phone to allow you to speak to Google Assistant to control Raspberry Pi's, You can tell the app to accept texts from the same phone it is installed on).