The document discusses the development and functionalities of a Morse code trainer skill for Alexa, created by a user group in Berlin. It highlights features such as customizable playback settings, global competition among users, and integration with light signals. Additionally, it mentions the use of advanced algorithms for phonetic accuracy and introduces two new SDKs for easier Alexa skill development.

1. Voice Interfaces User-Group Berlin
@KayLerch | 05.10.2016

2. • Started as a Hackster-Project in April 2016
• First published in May 2016
• Participated and won 1st prize in Alexa Hackster Contest
• Several user reviews (4 of 5 stars rating)
• Morse code trainer
• Former US coast guard
• Nostalgic people (a.k.a. older people)
• Morse Coder v2.0 is about to be released for English (GB, US) and German locale
• Skill implementation is open sourced at:
https://github.com/KayLerch/alexa-morse-coder
@ KayLerch | VUI UG Berlin

3. • Skill improves your comprehension for Morse-codes
• Morse code exercises (play back codes of random words)
• Encode any given name of your choice
• Let Morse Coders compete all around the globe (highscore game)
• Customize playback settings to fit your personal skill level
• Playback speed (9 to 30 wpm)
• Enable Farnsworth mode (longer pauses)
• Interactive exercises
• Letter cards in Alexa app
• Repeat playback
• Lightbox integration to return Morse codes as light-signals (not part of the public skill)
@ KayLerch | VUI UG Berlin

4. • Users were complaining about not having their correct answer being accepted by Alexa
• The reason for this is a natural lack of accurancy in comprehension
• Example: User says „sad“, Alexa understands „said“
• Morse skill simply checked for equality of the given word:
• whatTheUserSaid.equals(whatIsExpected);
• Double Metaphone for the rescue
• It‘s an algorithm which creates a hash of a word based on its pronunciation
• This results in same hashes for words being phonetic siblings (~ 80% reliability)
• Java‘s commons.codes libary provides this feature
• new DoubleMetaphone().isDoubleMetaphoneEqual(whatTheUserSaid, whatIsExpected);
• Double Metaphone / Metaphone / Soundex algorithms are optimized or English language
• There are similar algorithms for other languages (like Cologne phonetic for German language)
@ KayLerch | VUI UG Berlin

5. • On-the-fly image generation to show a played back code in the Alexa App
• There‘s a bunch of single images which will be composed to the exercise word
@ KayLerch | VUI UG Berlin

6. • For an ongoing exercise letter cards will have their letters hidden
@ KayLerch | VUI UG Berlin

7. @ KayLerch | VUI UG Berlin

8. @ KayLerch | VUI UG Berlin
• Wooden Lightbox returns light signals representing
a played back Morse code
• This Lightbox consists of:
• 32x32 LED matrix (19 x 19 cm)
• RaspberryPi 3
• Battery for taking the Lightbox with you on your
next lonely-on-an-island adventure ;-)
• Python-script on the Raspberry is subscribed to
an AWS IoT topic and receives MQTT messages
from the Lambda function

9. AWS
Lambda
Morse
Coder Skill
AWS
S3
S3 Bucket
Audio-Files
S3 Bucket
Image-Files
1 2 3
689
9
4
5
AWS
DynamoDB
AWS
IoT
7
AWS
EC2
MQTT
Topic
User Data
@ KayLerch | VUI UG Berlin

10. • Be aware that …
@ KayLerch | VUI UG Berlin

11. • This skill gave birth to two new SDKs which simplify things a lot for Java
developers who want to create Alexa skills:
• Alexa States SDK: https://github.com/KayLerch/alexa-skills-kit-states-java
Extends Alexa Skills Kit with an SDK to manage state of POJO models in your Alexa skills
• Alexa Tellask SDK: https://github.com/KayLerch/alexa-skills-kit-tellask-java
This SDK is an extension to the Alexa Skills SDK for Java. It provides a framework for handling
speechlet requests with multi-variant response utterances organized in YAML files that make it easy
to create localized skills. This SDK also lets you build your skill in declarative style and avoids a lot of
boilerplate code.
• Morse Coder skill is a good reference for understanding skill development with
States SDK and Tellask SDK
Check out: https://github.com/KayLerch/alexa-morse-coder
@ KayLerch | VUI UG Berlin