Building an Alexa Skill

30 Nov 2016

I recently bought an Amazon Echo, which I absolutely love. It’s great in the kitchen as a hands-free music player, as the speaker is really good, and has replaced the slightly unreliable Siri completely for setting timers when cooking.

Obviously I wanted to develop my own Alexa skill, so I’ve built one to tell me about the latest Halesowen Town scores and fixtures information. Right now there’s almost certainly an audience of one for it, but it makes me very happy!

Here’s a video showing the exciting things it does …

Technically the easiest way to write a skill is on AWS Lambda, Amazon’s on-demand compute engine. Alexa skills can run on Lambda with minimal setup, and looks a lot easier than running code on your own server.

The Alexa Skills SDK explains pretty well how to get set up - not always a given on Amazon’s platforms in my experience - so I won’t repeat anything here that isn’t covered in detail in the documentation.

In essense, to get your skill running you have to complete the following tasks:

1. Add a list of intents you want your skill to answer
   • You can add custom content slots for known lists of names (think Enum) e.g. I have a list of teams in Halesowen’s league to match against
2. Add sample phrases which will match to each of your intents
   • The content slots are used here e.g “FixtureIntent when is the game against {Team}”
3. Point to where the skill code runs
   • Trivial to do if you are using AWS Lambda, but you can use your own https server with a bit more effort
4. Upload your skill code in your AWS Lambda functions
   • The code can be written in Python, Java or Javascript/NodeJS - I chose the latter as I prefer the easy extensibility.

The example skill code for Lambda is pretty easy to understand and adapt as necessary. Note you can either update the code directly in the browser-based Lambda console, or upload a ZIP file containing your code. The latter is much preferable if you have any node modules you want to include in your solution.

My code simply loads existing JSON data from my server used in the iPhone/Android apps for the fixtures, results and latest score, parses it appropriately based on the user’s intent, and then returns a string which the Echo reads back to the user.

The voice recognition accuracy isn’t too bad - I suspect it struggles because of the slightly obscure names of some of the teams in the Northern Premier League!

All in all, it was pretty easy to knock together something based on existing data, and it’s really cool to be able to ask Alexa what the latest Halesowen score is. I look forward to be able to do this on Siri in about 3 years time at Apple’s currently glacial pace of opening up their systems.

The code is all available on Github at https://github.com/bravelocation/yeltzland-alexa/ which hopefully makes things a little clearer if you want to dive in and take a look.