Alexa Chromecast Skill

Allows Amazon Alexa to control Google Chromecast

Alexa, tell chromecast to pause

Alexa, tell chromecast to play

Alexa, tell chromecast to play MKBHD

Alexa, tell chromecast to play The Big Lebowski trailer

Alexa, tell chromecast to set the volume to 5

Alexa, tell chromecast to stop

Dependencies

Installation requires a UNIX environment with:

• BASH
• Python 2.7
• PIP

Setup and installation

1. Create an Amazon Web Services account
2. Run aws-setup.sh to create a Role, Lambda Function, and SNS Topic. (It will run aws configure, so have an key id and access key ready)
3. Go to developer.amazon.com and create a Skill mapped to the Lambda function ARN, intentSchemas and sample utterances are in config/.
4. Run src/local/main.py with the AWS_SNS_TOPIC_ARN and CHROMECAST_NAME environment variables.
5. Ask Alexa to tell Chromecast to do something.

Shell example

AWS_SNS_TOPIC_ARN=something CHROMECAST_NAME=Living\ Room ./src/local/main.py

Docker

The skill subscriber can be run with docker:

docker run --network="host" -it -e 'AWS_ACCESS_KEY_ID=...' -e 'AWS_SECRET_ACCESS_KEY=...' -e 'AWS_DEFAULT_REGION=...' -e 'AWS_SNS_TOPIC_ARN=...' lukechannings/alexa-skill-chromecast

Environment variables

The skill subscriber (local) uses these environment variables:

• AWS_SNS_TOPIC_ARN - AWS SNS Topic ARN (can be found in the .env file after running aws-setup.sh)

• CHROMECAST_NAME - Friendly name of the Chromecast to send commands to. (Defaults to 'Living Room')

• PORT - (Optional) Externally accessible port to expose the SNS handler on.

• AWS_ACCESS_KEY_ID - AWS User Access Key

• AWS_SECRET_ACCESS_KEY - AWS Secret Access Key

• AWS_DEFAULT_REGION - AWS Lambda and SNS Region (e.g. eu-west-1)

If you have run aws configure, you will not need to set AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, or AWS_DEFAULT_REGION.

Implementation

Alexa skills run in the cloud, but this skill needs to be on your local network to control the Chromecast. This skill implements a hybrid approach: the command is handled by Alexa on AWS, which sends a notification to your local server.

Alexa -> AWS Lambda -> AWS SNS (Simple Notification Service) -> Local server

The Lambda component is in src/lambda, and the local component is in src/local.

Scripts

aws-setup.sh

Sets up an AWS environment for the Alexa Skil:

1. Creates an IAM role for Alexa (with permissions for SNS)
2. Creates an SNS topic to communicate over
3. Creates a Lambda function

build-lambda-bundle.sh

Creates a lambda-bundle.zip, which can be uploaded to an AWS Lambda function.

aws-update-lambda.sh

Runs build-lambda-bundle and automatically uploads the bundle to AWS Lambda.