Suhaas Devalapally
Published

LEGO EV3 Baby Yoda - an Alexa Controlled EV3 Robot

A fun animatronic EV3 robot, controlled by voice commands with an Amazon Echo device!

IntermediateFull instructions provided4 hours499
LEGO EV3 Baby Yoda - an Alexa Controlled EV3 Robot

Things used in this project

Hardware components

EV3 Programming Brick / Kit
LEGO MindStorms EV3 Programming Brick / Kit
To make our model!
×1
Echo Dot
Amazon Alexa Echo Dot
To give voice commands to our robot!
×1
Flash Memory Card, SD Card
Flash Memory Card, SD Card
To write our operating system to our EV3 brick! You'll need a micro SD card, not the one shown in the picture.
×1
Brown Felt
To drape our precious Baby Yoda!
×1

Software apps and online services

VS Code
Microsoft VS Code
For our .py run file
Alexa Skills Kit
Amazon Alexa Alexa Skills Kit
For creating our Alexa skills
Alexa Voice Service
Amazon Alexa Alexa Voice Service
For creating and connecting our new Alexa Gadget

Story

Read more

Custom parts and enclosures

Lego Digital Designer File

Schematics

ports_table

Code

run.ini

INI
# Copyright 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
# 
# You may not use this file except in compliance with the terms and conditions 
# set forth in the accompanying LICENSE.TXT file.
#
# THESE MATERIALS ARE PROVIDED ON AN "AS IS" BASIS. AMAZON SPECIFICALLY DISCLAIMS, WITH 
# RESPECT TO THESE MATERIALS, ALL WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, INCLUDING 
# THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.

[GadgetSettings]
amazonId = PASTE_ID_HERE
alexaGadgetSecret = PASTE_GS_HERE

[GadgetCapabilities]
Custom.Mindstorms.Gadget = 1.0

run.py

Python
#!/usr/bin/env python3
# Copyright 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
# 
# You may not use this file except in compliance with the terms and conditions 
# set forth in the accompanying LICENSE.TXT file.
#
# THESE MATERIALS ARE PROVIDED ON AN "AS IS" BASIS. AMAZON SPECIFICALLY DISCLAIMS, WITH 
# RESPECT TO THESE MATERIALS, ALL WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, INCLUDING 
# THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.

import os
import sys
import time
import logging
import json
import random
import threading
from enum import Enum

from agt import AlexaGadget

from ev3dev2.led import Leds
from ev3dev2.sound import Sound
from ev3dev2.motor import OUTPUT_A, OUTPUT_B, OUTPUT_C, MoveTank, SpeedPercent, MediumMotor
from ev3dev2.sensor.lego import InfraredSensor

# Set the logging level to INFO to see messages from AlexaGadget
logging.basicConfig(level=logging.INFO, stream=sys.stdout, format='%(message)s')
logging.getLogger().addHandler(logging.StreamHandler(sys.stderr))
logger = logging.getLogger(__name__)


class Direction(Enum):
    """
    The list of directional commands and their variations.
    These variations correspond to the skill slot values.
    """
    FORWARD = ['forward', 'forwards', 'go forward']
    BACKWARD = ['back', 'backward', 'backwards', 'go backwards']
    LEFT = ['left', 'go left']
    RIGHT = ['right', 'go right']
    STOP = ['stop', 'brake', 'halt']


class Command(Enum):
    """
    The list of preset commands and their invocation variation.
    These variations correspond to the skill slot values.
    """
    SENTRY = ['broth', 'bone broth', 'sorgan', 'sorgen']
    PATROL = ['patrol', 'patrol mode']
    FIRE_ONE = ['drink', 'drink up']


class EventName(Enum):
    """
    The list of custom event name sent from this gadget
    """
    SENTRY = "Sentry"
    PROXIMITY = "Proximity"
    SPEECH = "Speech"


class MindstormsGadget(AlexaGadget):
    """
    A Mindstorms gadget that can perform bi-directional interaction with an Alexa skill.
    """

    def __init__(self):
        """
        Performs Alexa Gadget initialization routines and ev3dev resource allocation.
        """
        super().__init__()

        # Robot state
        self.sentry_mode = False
        self.patrol_mode = False

        # Connect two large motors on output ports B and C
        self.drive = MoveTank(OUTPUT_B, OUTPUT_C)
        self.weapon = MediumMotor(OUTPUT_A)
        self.sound = Sound()
        self.leds = Leds()
        self.ir = InfraredSensor()

        # Start threads
        threading.Thread(target=self._patrol_thread, daemon=True).start()
        threading.Thread(target=self._proximity_thread, daemon=True).start()

    def on_connected(self, device_addr):
        """
        Gadget connected to the paired Echo device.
        :param device_addr: the address of the device we connected to
        """
        self.leds.set_color("LEFT", "GREEN")
        self.leds.set_color("RIGHT", "GREEN")
        logger.info("{} connected to Echo device".format(self.friendly_name))

    def on_disconnected(self, device_addr):
        """
        Gadget disconnected from the paired Echo device.
        :param device_addr: the address of the device we disconnected from
        """
        self.leds.set_color("LEFT", "BLACK")
        self.leds.set_color("RIGHT", "BLACK")
        logger.info("{} disconnected from Echo device".format(self.friendly_name))

    def on_custom_mindstorms_gadget_control(self, directive):
        """
        Handles the Custom.Mindstorms.Gadget control directive.
        :param directive: the custom directive with the matching namespace and name
        """
        try:
            payload = json.loads(directive.payload.decode("utf-8"))
            print("Control payload: {}".format(payload), file=sys.stderr)
            control_type = payload["type"]
            if control_type == "move":

                # Expected params: [direction, duration, speed]
                self._move(payload["direction"], int(payload["duration"]), int(payload["speed"]))

            if control_type == "command":
                # Expected params: [command]
                self._activate(payload["command"])

        except KeyError:
            print("Missing expected parameters: {}".format(directive), file=sys.stderr)

    def _move(self, direction, duration: int, speed: int, is_blocking=False):
        """
        Handles move commands from the directive.
        Right and left movement can under or over turn depending on the surface type.
        :param direction: the move direction
        :param duration: the duration in seconds
        :param speed: the speed percentage as an integer
        :param is_blocking: if set, motor run until duration expired before accepting another command
        """
        print("Move command: ({}, {}, {}, {})".format(direction, speed, duration, is_blocking), file=sys.stderr)
        if direction in Direction.FORWARD.value:
            self.drive.on_for_seconds(SpeedPercent(speed), SpeedPercent(speed), duration, block=is_blocking)

        if direction in Direction.BACKWARD.value:
            self.drive.on_for_seconds(SpeedPercent(-speed), SpeedPercent(-speed), duration, block=is_blocking)

        if direction in (Direction.RIGHT.value + Direction.LEFT.value):
            self._turn(direction, speed)
            self.drive.on_for_seconds(SpeedPercent(speed), SpeedPercent(speed), duration, block=is_blocking)

        if direction in Direction.STOP.value:
            self.drive.off()
            self.patrol_mode = False

    def _activate(self, command, speed=50):
        """
        Handles preset commands.
        :param command: the preset command
        :param speed: the speed if applicable
        """
        print("Activate command: ({}, {})".format(command, speed), file=sys.stderr)
        if command in Command.PATROL.value:
            # Set patrol mode to resume patrol thread processing
            self.patrol_mode = True

        if command in Command.SENTRY.value:
            self.sentry_mode = True
            self._send_event(EventName.SPEECH, {'speechOut': "Bone broth, For the little one."})

            # Perform Shuffle posture
            self.drive.on_for_seconds(SpeedPercent(80), SpeedPercent(-80), 0.2)
            time.sleep(0.3)
            self.drive.on_for_seconds(SpeedPercent(-40), SpeedPercent(40), 0.2)

            self.leds.set_color("LEFT", "YELLOW", 1)
            self.leds.set_color("RIGHT", "YELLOW", 1)

        if command in Command.FIRE_ONE.value:
            print("Fire one", file=sys.stderr)
            self.weapon.on_for_rotations(SpeedPercent(-5), 0.25)
            time.sleep(3)
            self.weapon.on_for_rotations(SpeedPercent(5), 0.05)
            self.weapon.on_for_rotations(SpeedPercent(-5), 0.05)
            self.weapon.on_for_rotations(SpeedPercent(5), 0.25)
            self._send_event(EventName.SENTRY, {'fire': 1})
            self.sentry_mode = False
            print("Bone broth consumed, alarm reset", file=sys.stderr)
            self.leds.set_color("LEFT", "RED", 1)
            self.leds.set_color("RIGHT", "GREEN", 1)
    
    def _turn(self, direction, speed):
        """
        Turns based on the specified direction and speed.
        Calibrated for hard smooth surface.
        :param direction: the turn direction
        :param speed: the turn speed
        """
        if direction in Direction.LEFT.value:
            self.drive.on_for_seconds(SpeedPercent(0), SpeedPercent(speed), 2)

        if direction in Direction.RIGHT.value:
            self.drive.on_for_seconds(SpeedPercent(speed), SpeedPercent(0), 2)

    def _send_event(self, name: EventName, payload):
        """
        Sends a custom event to trigger a sentry action.
        :param name: the name of the custom event
        :param payload: the sentry JSON payload
        """
        self.send_custom_event('Custom.Mindstorms.Gadget', name.value, payload)

    def _proximity_thread(self):
        """
        Monitors the distance between the robot and an obstacle when sentry mode is activated.
        If the minimum distance is breached, send a custom event to trigger action on
        the Alexa skill.
        """
        count = 0
        while True:
            while self.sentry_mode:
                distance = self.ir.proximity
                print("Proximity: {}".format(distance), file=sys.stderr)
                count = count + 1 if distance < 10 else 0
                if count > 3:
                    print("Proximity breached. Sending event to skill", file=sys.stderr)
                    self.leds.set_color("LEFT", "RED", 1)
                    self.leds.set_color("RIGHT", "RED", 1)

                    self._send_event(EventName.PROXIMITY, {'distance': distance})
                    self.sentry_mode = False

                time.sleep(0.2)
            time.sleep(1)

    def _patrol_thread(self):
        """
        Performs random movement when patrol mode is activated.
        """
        while True:
            while self.patrol_mode:
                print("Patrol mode activated randomly picks a path", file=sys.stderr)
                direction = random.choice(list(Direction))
                duration = random.randint(5, 15)
                speed = random.randint(1, 4) * 25

                while direction == Direction.STOP:
                    direction = random.choice(list(Direction))

                # direction: all except stop, duration: 1-5s, speed: 25, 50, 75, 100
                self._move(direction.value[0], duration, speed)
                time.sleep(duration)
            time.sleep(1)


if __name__ == '__main__':

    gadget = MindstormsGadget()

    # Set LCD font and turn off blinking LEDs
    os.system('setfont Lat7-Terminus12x6')
    gadget.leds.set_color("LEFT", "BLACK")
    gadget.leds.set_color("RIGHT", "BLACK")

    # Startup sequence
    gadget.sound.play_song((('C4', 'e'), ('D4', 'e'), ('E5', 'q')))
    gadget.leds.set_color("LEFT", "GREEN")
    gadget.leds.set_color("RIGHT", "GREEN")

    # Gadget main entry point
    gadget.main()

    # Shutdown sequence
    gadget.sound.play_song((('E5', 'e'), ('C4', 'e')))
    gadget.leds.set_color("LEFT", "BLACK")
    gadget.leds.set_color("RIGHT", "BLACK")

index.js

JavaScript
/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * You may not use this file except in compliance with the terms and conditions 
 * set forth in the accompanying LICENSE.TXT file.
 *
 * THESE MATERIALS ARE PROVIDED ON AN "AS IS" BASIS. AMAZON SPECIFICALLY DISCLAIMS, WITH 
 * RESPECT TO THESE MATERIALS, ALL WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, INCLUDING 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
*/

// This skill sample demonstrates how to send directives and receive events from an Echo connected gadget.
// This skill uses the Alexa Skills Kit SDK (v2). Please visit https://alexa.design/cookbook for additional
// examples on implementing slots, dialog management, session persistence, api calls, and more.

const Alexa = require('ask-sdk-core');
const Util = require('./util');
const Common = require('./common');

// The audio tag to include background music
const BG_MUSIC = '<audio src="soundbank://soundlibrary/ui/gameshow/amzn_ui_sfx_gameshow_waiting_loop_30s_01"></audio>';

// The namespace of the custom directive to be sent by this skill
const NAMESPACE = 'Custom.Mindstorms.Gadget';

// The name of the custom directive to be sent this skill
const NAME_CONTROL = 'control';

const LaunchRequestHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'LaunchRequest';
    },
    handle: async function(handlerInput) {

        const request = handlerInput.requestEnvelope;
        const { apiEndpoint, apiAccessToken } = request.context.System;
        const apiResponse = await Util.getConnectedEndpoints(apiEndpoint, apiAccessToken);
        if ((apiResponse.endpoints || []).length === 0) {
            return handlerInput.responseBuilder
            .speak(`I couldn't find an EV3 Brick connected to this Echo device. Please check to make sure your EV3 Brick is connected, and try again.`)
            .getResponse();
        }

        // Store the gadget endpointId to be used in this skill session
        const endpointId = apiResponse.endpoints[0].endpointId || [];
        Util.putSessionAttribute(handlerInput, 'endpointId', endpointId);

        // Set skill duration to 5 minutes (ten 30-seconds interval)
        Util.putSessionAttribute(handlerInput, 'duration', 10);

        // Set the token to track the event handler
        const token = handlerInput.requestEnvelope.request.requestId;
        Util.putSessionAttribute(handlerInput, 'token', token);

        let speechOutput = "Welcome, voice interface activated";
        return handlerInput.responseBuilder
            .speak(speechOutput + BG_MUSIC)
            .addDirective(Util.buildStartEventHandler(token,60000, {}))
            .getResponse();
    }
};

// Add the speed value to the session attribute.
// This allows other intent handler to use the specified speed value
// without asking the user for input.
const SetSpeedIntentHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'IntentRequest'
            && Alexa.getIntentName(handlerInput.requestEnvelope) === 'SetSpeedIntent';
    },
    handle: function (handlerInput) {

        // Bound speed to (1-100)
        let speed = Alexa.getSlotValue(handlerInput.requestEnvelope, 'Speed');
        speed = Math.max(1, Math.min(100, parseInt(speed)));
        Util.putSessionAttribute(handlerInput, 'speed', speed);

        let speechOutput = `speed set to ${speed} percent.`;
        return handlerInput.responseBuilder
            .speak(speechOutput + BG_MUSIC)
            .getResponse();
    }
};

// Construct and send a custom directive to the connected gadget with
// data from the MoveIntent.
const MoveIntentHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'IntentRequest'
            && Alexa.getIntentName(handlerInput.requestEnvelope) === 'MoveIntent';
    },
    handle: function (handlerInput) {
        const request = handlerInput.requestEnvelope;
        const direction = Alexa.getSlotValue(request, 'Direction');

        // Duration is optional, use default if not available
        const duration = Alexa.getSlotValue(request, 'Duration') || "5";

        // Get data from session attribute
        const attributesManager = handlerInput.attributesManager;
        const speed = attributesManager.getSessionAttributes().speed || "20";
        const endpointId = attributesManager.getSessionAttributes().endpointId || [];

        // Construct the directive with the payload containing the move parameters
        let directive = Util.build(endpointId, NAMESPACE, NAME_CONTROL,
            {
                type: 'move',
                direction: direction,
                duration: duration,
                speed: speed
            });

        const speechOutput = (direction === "brake")
            ?  "Applying brake"
            : `${direction} ${duration} seconds at ${speed} percent speed`;

        return handlerInput.responseBuilder
            .speak(speechOutput + BG_MUSIC)
            .addDirective(directive)
            .getResponse();
    }
};

// Construct and send a custom directive to the connected gadget with data from
// the SetCommandIntent.
const SetCommandIntentHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'IntentRequest'
            && Alexa.getIntentName(handlerInput.requestEnvelope) === 'SetCommandIntent';
    },
    handle: function (handlerInput) {

        let command = Alexa.getSlotValue(handlerInput.requestEnvelope, 'Command');
        if (!command) {
            return handlerInput.responseBuilder
                .speak("Can you repeat that?")
                .withShouldEndSession(false)
                .getResponse();
        }

        const attributesManager = handlerInput.attributesManager;
        let endpointId = attributesManager.getSessionAttributes().endpointId || [];
        let speed = attributesManager.getSessionAttributes().speed || "20";

        // Construct the directive with the payload containing the move parameters
        let directive = Util.build(endpointId, NAMESPACE, NAME_CONTROL,
            {
                type: 'command',
                command: command,
                speed: speed
            });

        let speechOutput = `command ${command} activated`;
        if (command === 'sentry' || command === 'sentry mode' || command === 'broth') {
            speechOutput = '';
        }
        return handlerInput.responseBuilder
            .speak(speechOutput + BG_MUSIC)
            .addDirective(directive)
            .getResponse();
    }
};

const EventsReceivedRequestHandler = {
    // Checks for a valid token and endpoint.
    canHandle(handlerInput) {
        let { request } = handlerInput.requestEnvelope;
        console.log('Request type: ' + Alexa.getRequestType(handlerInput.requestEnvelope));
        if (request.type !== 'CustomInterfaceController.EventsReceived') return false;

        const attributesManager = handlerInput.attributesManager;
        let sessionAttributes = attributesManager.getSessionAttributes();
        let customEvent = request.events[0];

        // Validate event token
        if (sessionAttributes.token !== request.token) {
            console.log("Event token doesn't match. Ignoring this event");
            return false;
        }

        // Validate endpoint
        let requestEndpoint = customEvent.endpoint.endpointId;
        if (requestEndpoint !== sessionAttributes.endpointId) {
            console.log("Event endpoint id doesn't match. Ignoring this event");
            return false;
        }
        return true;
    },
    handle(handlerInput) {

        console.log("== Received Custom Event ==");
        let customEvent = handlerInput.requestEnvelope.request.events[0];
        let payload = customEvent.payload;
        let name = customEvent.header.name;

        let speechOutput;
        if (name === 'Proximity') {
            let distance = parseInt(payload.distance);
            if (distance < 30) {
                let speechOutput = "What should I do?";
                return handlerInput.responseBuilder
                    .speak(speechOutput, "REPLACE_ALL")
                    .withShouldEndSession(false)
                    .getResponse();
            }
        } else if (name === 'Sentry') {
            if ('fire' in payload) {
                speechOutput = "Yum yum!";
            }

        } else if (name === 'Speech') {
            speechOutput = payload.speechOut;

        } else {
            speechOutput = "Event not recognized. Awaiting new command.";
        }
        return handlerInput.responseBuilder
            .speak(speechOutput + BG_MUSIC, "REPLACE_ALL")
            .getResponse();
    }
};
const ExpiredRequestHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'CustomInterfaceController.Expired'
    },
    handle(handlerInput) {
        console.log("== Custom Event Expiration Input ==");

        // Set the token to track the event handler
        const token = handlerInput.requestEnvelope.request.requestId;
        Util.putSessionAttribute(handlerInput, 'token', token);

        const attributesManager = handlerInput.attributesManager;
        let duration = attributesManager.getSessionAttributes().duration || 0;
        if (duration > 0) {
            Util.putSessionAttribute(handlerInput, 'duration', --duration);

            // Extends skill session
            const speechOutput = `${duration} minutes remaining.`;
            return handlerInput.responseBuilder
                .addDirective(Util.buildStartEventHandler(token, 60000, {}))
                .speak(speechOutput + BG_MUSIC)
                .getResponse();
        }
        else {
            // End skill session
            return handlerInput.responseBuilder
                .speak("Skill duration expired. Goodbye.")
                .withShouldEndSession(true)
                .getResponse();
        }
    }
};

// The SkillBuilder acts as the entry point for your skill, routing all request and response
// payloads to the handlers above. Make sure any new handlers or interceptors you've
// defined are included below. The order matters - they're processed top to bottom.
exports.handler = Alexa.SkillBuilders.custom()
    .addRequestHandlers(
        LaunchRequestHandler,
        SetSpeedIntentHandler,
        SetCommandIntentHandler,
        MoveIntentHandler,
        EventsReceivedRequestHandler,
        ExpiredRequestHandler,
        Common.HelpIntentHandler,
        Common.CancelAndStopIntentHandler,
        Common.SessionEndedRequestHandler,
        Common.IntentReflectorHandler, // make sure IntentReflectorHandler is last so it doesn't override your custom intent handlers
    )
    .addRequestInterceptors(Common.RequestInterceptor)
    .addErrorHandlers(
        Common.ErrorHandler,
    )
    .lambda();

common.js

JavaScript
/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * You may not use this file except in compliance with the terms and conditions 
 * set forth in the accompanying LICENSE.TXT file.
 *
 * THESE MATERIALS ARE PROVIDED ON AN "AS IS" BASIS. AMAZON SPECIFICALLY DISCLAIMS, WITH 
 * RESPECT TO THESE MATERIALS, ALL WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, INCLUDING 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
*/

'use strict'

const Alexa = require('ask-sdk-core');

const HelpIntentHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'IntentRequest'
            && Alexa.getIntentName(handlerInput.requestEnvelope) === 'AMAZON.HelpIntent';
    },
    handle(handlerInput) {
        const speakOutput = 'You can say hello to me! How can I help?';

        return handlerInput.responseBuilder
            .speak(speakOutput)
            .reprompt(speakOutput)
            .getResponse();
    }
};
const CancelAndStopIntentHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'IntentRequest'
            && (Alexa.getIntentName(handlerInput.requestEnvelope) === 'AMAZON.CancelIntent'
                || Alexa.getIntentName(handlerInput.requestEnvelope) === 'AMAZON.StopIntent');
    },
    handle(handlerInput) {
        const speakOutput = 'Goodbye!';
        return handlerInput.responseBuilder
            .speak(speakOutput)
            .getResponse();
    }
};
const SessionEndedRequestHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'SessionEndedRequest';
    },
    handle(handlerInput) {
        // Any cleanup logic goes here.
        return handlerInput.responseBuilder.getResponse();
    }
};

// The intent reflector is used for interaction model testing and debugging.
// It will simply repeat the intent the user said. You can create custom handlers
// for your intents by defining them above, then also adding them to the request
// handler chain below.
const IntentReflectorHandler = {
    canHandle(handlerInput) {
        return Alexa.getRequestType(handlerInput.requestEnvelope) === 'IntentRequest';
    },
    handle(handlerInput) {
        const intentName = Alexa.getIntentName(handlerInput.requestEnvelope);
        const speakOutput = `You just triggered ${intentName}`;

        return handlerInput.responseBuilder
            .speak(speakOutput)
            .reprompt("I don't understand this command, try again")
            .getResponse();
    }
};

// Generic error handling to capture any syntax or routing errors. If you receive an error
// stating the request handler chain is not found, you have not implemented a handler for
// the intent being invoked or included it in the skill builder below.
const ErrorHandler = {
    canHandle() {
        return true;
    },
    handle(handlerInput, error) {
        console.log(`~~~~ Error handled: ${error.stack}`);
        const speakOutput = `Sorry, I had trouble doing what you asked. Please try again.`;

        return handlerInput.responseBuilder
            .speak(speakOutput)
            .reprompt(speakOutput)
            .getResponse();
    }
};

// The request interceptor is used for request handling testing and debugging.
// It will simply log the request in raw json format before any processing is performed.
const RequestInterceptor = {
    process(handlerInput) {
        let { attributesManager, requestEnvelope } = handlerInput;
        let sessionAttributes = attributesManager.getSessionAttributes();

        // Log the request for debug purposes.
        console.log(`=====Request==${JSON.stringify(requestEnvelope)}`);
        console.log(`=========SessionAttributes==${JSON.stringify(sessionAttributes, null, 2)}`);
    }
};

module.exports = {
    HelpIntentHandler,
    CancelAndStopIntentHandler,
    SessionEndedRequestHandler,
    IntentReflectorHandler,
    ErrorHandler,
    RequestInterceptor
    };

package.json

JSON
{
  "name": "agt-mindstorms",
  "version": "1.1.0",
  "description": "A sample skill demonstrating how to use AGT with Lego Mindstorms",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Amazon Alexa",
  "license": "ISC",
  "dependencies": {
    "ask-sdk-core": "^2.6.0",
    "ask-sdk-model": "^1.18.0",
    "aws-sdk": "^2.326.0",
    "request": "^2.81.0",
    "lodash": "^4.17.11"
  }
}

util.js

JavaScript
/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * You may not use this file except in compliance with the terms and conditions
 * set forth in the accompanying LICENSE.TXT file.
 *
 * THESE MATERIALS ARE PROVIDED ON AN "AS IS" BASIS. AMAZON SPECIFICALLY DISCLAIMS, WITH
 * RESPECT TO THESE MATERIALS, ALL WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, INCLUDING
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
*/

'use strict';

const Https = require('https');
const AWS = require('aws-sdk');
const Escape = require('lodash/escape');

const s3SigV4Client = new AWS.S3({
    signatureVersion: 'v4'
});

/**
 * Get the authenticated URL to access the S3 Object. This URL expires after 60 seconds.
 * @param s3ObjectKey - the S3 object key
 * @returns {string} the pre-signed S3 URL
 */
exports.getS3PreSignedUrl = function getS3PreSignedUrl(s3ObjectKey) {

    const bucketName = process.env.S3_PERSISTENCE_BUCKET;
    return Escape(s3SigV4Client.getSignedUrl('getObject', {
        Bucket: bucketName,
        Key: s3ObjectKey,
        Expires: 60 // the Expires is capped for 1 minute
    }));
};

/**
 * Builds a directive to start the EventHandler.
 * @param token - a unique identifier to track the event handler
 * @param {number} timeout - the duration to wait before sending back the expiration
 * payload to the skill.
 * @param payload - the expiration json payload
 * @see {@link https://developer.amazon.com/docs/alexa-gadgets-toolkit/receive-custom-event-from-gadget.html#start}
 */
exports.buildStartEventHandler = function (token, timeout = 30000, payload)  {
    return {
        type: "CustomInterfaceController.StartEventHandler",
        token: token,
        expiration : {
            durationInMilliseconds: timeout,
            expirationPayload: payload
        }
    };
};

/**
 *
 * Builds a directive to stops the active event handler.
 * The event handler is identified by the cached token in the session attribute.
 * @param {string} handlerInput - the context from Alexa Service
 * @see {@link https://developer.amazon.com/docs/alexa-gadgets-toolkit/receive-custom-event-from-gadget.html#stop}
 */
exports.buildStopEventHandlerDirective = function (handlerInput) {

    let token = handlerInput.attributesManager.getSessionAttributes().token || '';
    return {
        "type": "CustomInterfaceController.StopEventHandler",
        "token": token
    }
};

/**
 * Build a custom directive payload to the gadget with the specified endpointId
 * @param {string} endpointId - the gadget endpoint Id
 * @param {string} namespace - the namespace of the skill
 * @param {string} name - the name of the skill within the scope of this namespace
 * @param {object} payload - the payload data
 * @see {@link https://developer.amazon.com/docs/alexa-gadgets-toolkit/send-gadget-custom-directive-from-skill.html#respond}
 */
exports.build = function (endpointId, namespace, name, payload) {
    // Construct the custom directive that needs to be sent
    // Gadget should declare the capabilities in the discovery response to
    // receive the directives under the following namespace.
    return {
        type: 'CustomInterfaceController.SendDirective',
        header: {
            name: name,
            namespace: namespace
        },
        endpoint: {
            endpointId: endpointId
        },
        payload
    };
};

/**
 * A convenience routine to add the a key-value pair to the session attribute.
 * @param handlerInput - the context from Alexa Service
 * @param key - the key to be added
 * @param value - the value be added
 */
exports.putSessionAttribute = function(handlerInput, key, value) {
    const attributesManager = handlerInput.attributesManager;
    let sessionAttributes = attributesManager.getSessionAttributes();
    sessionAttributes[key] = value;
    attributesManager.setSessionAttributes(sessionAttributes);
};


/**
 * To get a list of all the gadgets that meet these conditions,
 * Call the Endpoint Enumeration API with the apiEndpoint and apiAccessToken to
 * retrieve the list of all connected gadgets.
 *
 * @param {string} apiEndpoint - the Endpoint API url
 * @param {string} apiAccessToken  - the token from the session object in the Alexa request
 * @see {@link https://developer.amazon.com/docs/alexa-gadgets-toolkit/send-gadget-custom-directive-from-skill.html#call-endpoint-enumeration-api}
 */
exports.getConnectedEndpoints = function(apiEndpoint, apiAccessToken) {

    // The preceding https:// need to be stripped off before making the call
    apiEndpoint = (apiEndpoint || '').replace('https://', '');

    return new Promise(((resolve, reject) => {

        const options = {
            host: apiEndpoint,
            path: '/v1/endpoints',
            method: 'GET',
            headers: {
                'Content-Type': 'application/json',
                'Authorization': 'Bearer ' + apiAccessToken
            }
        };

        const request = Https.request(options, (response) => {
            response.setEncoding('utf8');
            let returnData = '';
            response.on('data', (chunk) => {
                returnData += chunk;
            });

            response.on('end', () => {
                resolve(JSON.parse(returnData));
            });

            response.on('error', (error) => {
                reject(error);
            });
        });
        request.end();
    }));
};

model.json

JSON
{
  "interactionModel": {
      "languageModel": {
          "invocationName": "mindstorms",
          "intents": [
              {
                  "name": "AMAZON.CancelIntent",
                  "samples": []
              },
              {
                  "name": "AMAZON.HelpIntent",
                  "samples": []
              },
              {
                  "name": "AMAZON.StopIntent",
                  "samples": []
              },
              {
                  "name": "AMAZON.NavigateHomeIntent",
                  "samples": []
              },
              {
                  "name": "MoveIntent",
                  "slots": [
                      {
                          "name": "Direction",
                          "type": "DirectionType"
                      },
                      {
                          "name": "Duration",
                          "type": "AMAZON.NUMBER"
                      }
                  ],
                  "samples": [
                      "{Direction} now",
                      "{Direction} {Duration} seconds",
                      "move {Direction} for {Duration} seconds",
                      "go {Direction}",
                      "{Direction}"
                  ]
              },
              {
                  "name": "SetSpeedIntent",
                  "slots": [
                      {
                          "name": "Speed",
                          "type": "AMAZON.NUMBER"
                      }
                  ],
                  "samples": [
                      "set speed {Speed} percent",
                      "set {Speed} percent speed",
                      "set speed to {Speed} percent"
                  ]
              },
              {
                  "name": "SetCommandIntent",
                  "slots": [
                      {
                          "name": "Command",
                          "type": "CommandType"
                      }
                  ],
                  "samples": [
                      "activate {Command} mode",
                      "activate {Command}",
                      "{Command} up",
                      "Welcome to planet {Command}",
                      "{Command}"
                  ]
              }
          ],
          "types": [
              {
                  "name": "DirectionType",
                  "values": [
                      {
                          "name": {
                              "value": "brake"
                          }
                      },
                      {
                          "name": {
                              "value": "go backward"
                          }
                      },
                      {
                        "name": {
                            "value": "go backwards"
                        }
                    },
                      {
                          "name": {
                              "value": "go forward"
                          }
                      },
                      {
                          "name": {
                              "value": "go right"
                          }
                      },
                      {
                          "name": {
                              "value": "go left"
                          }
                      },
                      {
                          "name": {
                              "value": "right"
                          }
                      },
                      {
                          "name": {
                              "value": "left"
                          }
                      },
                      {
                          "name": {
                              "value": "backwards"
                          }
                      },
                      {
                          "name": {
                              "value": "backward"
                          }
                      },
                      {
                          "name": {
                              "value": "forwards"
                          }
                      },
                      {
                          "name": {
                              "value": "forward"
                          }
                      }
                  ]
              },
              {
                  "name": "CommandType",
                  "values": [
                      {
                          "name": {
                              "value": "patrol"
                          }
                      },
                      {
                          "name": {
                              "value": "broth"
                          }
                      },
                      {
                          "name": {
                              "value": "bone broth"
                          }
                      },
                      {
                          "name": {
                              "value": "drink"
                          }
                      },
                      {
                          "name": {
                              "value": "sorgan"
                          }
                      },
                      {
                          "name": {
                              "value": "sorgen"
                          }
                      }
                  ]
              }
          ]
      }
  }
}

Credits

Suhaas Devalapally

Suhaas Devalapally

1 project • 0 followers

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