Launch a Script Using Alexa Voice Commands

In a previous post, I showed how you can build a smart mirror with an Alexa voice assistant on board. The MagicMirror software and Alexa voice assistant were both hosted on a Raspberry Pi, but unfortunately there was no obvious way to get Alexa to control the smart mirror, or deliver commands to the Raspberry Pi.

I have now found a solution that is free, reliable, and very flexible. This is done by writing an Alexa Skill that adds a message to a cloud hosted queue based on your voice command. The Raspberry Pi repeatedly checks this queue for new messages, and runs customizable behaviour based on message contents. This is not limited to smart mirror applications, or Raspberry Pis. It can be used to launch any script you want on any platform that will connect to Amazon's SQS.

Here is a demonstration, and high level overview of how it works:

and a follow up demonstrating an extension of this idea:

In this tutorial I will focus on just using this to simply turn the smart mirror on and off. Adding your own scripts should then be fairly straight forward,

The steps will be as follows:

1. Create a Queue using the Amazon Simple Queue Service (SQS)
2. Write some python code to read and write to this queue
3. Write a Lambda Function that posts messages to the queue
4. Write an Alexa Skill that calls the Lambda Function
5. Schedule a task on your Raspberry Pi to read queue messages and take appropriate action.

DIY Smart Mirror ft. Alexa

Materials

1. Computer Monitor. Buy used and look for cable inputs that point down or sideways instead of straight out. 22" recommended (I used Acer AL2216 )
2. Video cable. Whatever fits your monitor (I used HDMI to DVI adapter)
3. Raspberry Pi 3, 16GB Micro SD Card, 5V Micro USB power supply, any RPi case
4. Wood. I bought four 3ft lengths of 3"x1"
5. 8 Angle brackets
6. Short wood screws.
7. Gorilla glue.
8. Electrical tape.
9. Extension Cord with multiple plugs.
10. 50cm x 70cm Ikea STROMBY frame.
11. Gila Mirrored Window Film 
12. USB Sound Card, Lapel Mic, any USB powered speaker *

*Bonus Alexa Materials

Additional required tools/supplies are: scotch tape, a squirt bottle, dish soap, a drill or screwdriver, exacto knife, scissors, and a saw.

March 10, 2018 update: I'm currently in the process of trying out an actual two way mirror as well instead of the window film. If you're interested in this I can recommend this mirror which comes in several sizes. I'll have a post coming soon with instructions for how to mount it.

Creating the Two Way Mirror

The two way mirror is the most essential part of this build. To create this component, you just apply Gila Mirrored Window Film to any piece of glass or acrylic. This works equally well for glass and acrylic, and only takes about 15 minutes.

DIY Alexa Raspberry Pi Voice Assistant

Amazon did something really cool. They made their Alexa voice assistant code open source and cross platform. That means instead of buying their Amazon Echo to get a home assistant, you can simply install it on any system you want.

It's actually a fairly straightforward project, especially if you've setup a Raspberry Pi before (or eight #fromthevault)! Basically you're just installing an application, and setting up a microphone and speaker. Nothing fancy.

There are already some great guides for getting started too for both Raspberry Pi and Alexa. I'm just going to direct you to these, give a rough overview, and add some additional tips.

Here it is in action:

Shopping List

For equipment, you'll need:

1. A Raspberry Pi 3 with SD card and USB micro power source:

• Raspberry Pi 3 Model B Starter Kit