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This is based on an existing Mindstorms project our family built. The music box can play any song on a xylophone and the songs can be configured by inserting push-pins in the oatmeal container attached to the robot. As the large motors rotate the oatmeal container, the push-pins make contact with small arms of the assembly to play notes on the xylophone. We modified this project to enable Alexa voice commands It can now use the command "Play Christmas Music" to play the song instead of using the push-button switch.
Here is the link to the original project: https://teachkidsengineering.com/lego-mindstorms-music-box/
The only small changes we made to the build of the original robot: We connected the large motors to the EV3 outputs B and C (to match the existing Python code) and we connected a medium motor to output A (to satisfy existing code). Both of these changes can be easily modified in the Python program, but this was a simple work-around.
Here is the robot playing a Christmas song before we added the new Alexa voice command:
We followed all of the instructions from the LEGO Mindstorms Voice Challenge to get mission3 up and running. Mission3 has good examples of creating new voice commands on the Alexa Developer console: https://www.hackster.io/alexagadgets/lego-mindstorms-voice-challenge-mission-3-4ed812
Once mission3 was working, we copied to code to a new project and made the below changes to add our command for "Play Christmas Music".
This is a pretty easy project to build. The build instructions are attached in pdf form, but we also recommend you watch the additional "How to Build" video for a quick overview. https://teachkidsengineering.com/lego-mindstorms-music-box/
/*
* 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 sample demonstrates sending directives to an Echo connected gadget from an Alexa skill
// using 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 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) {
let request = handlerInput.requestEnvelope;
let { apiEndpoint, apiAccessToken } = request.context.System;
let 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
let endpointId = apiResponse.endpoints[0].endpointId || [];
Util.putSessionAttribute(handlerInput, 'endpointId', endpointId);
return handlerInput.responseBuilder
.speak("Welcome, you can start issuing move commands")
.reprompt("Awaiting commands")
.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);
return handlerInput.responseBuilder
.speak(`speed set to ${speed} percent.`)
.reprompt("awaiting command")
.getResponse();
}
};
// Construct and send a custom directive to the connected gadget with
// data from the MoveIntent request.
const MoveIntentHandler = {
canHandle(handlerInput) {
return Alexa.getRequestType(handlerInput.requestEnvelope) === 'IntentRequest'
&& Alexa.getIntentName(handlerInput.requestEnvelope) === 'MoveIntent';
},
handle: function (handlerInput) {
const request = handlerInput.requestEnvelope;
// Direction is optional, use default if not available
const direction = Alexa.getSlotValue(request, 'Direction') || "forward";
// Duration is optional, use default if not available
const duration = Alexa.getSlotValue(request, 'Duration') || "30";
// Get data from session attribute
const attributesManager = handlerInput.attributesManager;
const speed = attributesManager.getSessionAttributes().speed || "3";
const endpointId = attributesManager.getSessionAttributes().endpointId || [];
// Construct the directive with the payload containing the move parameters
const directive = Util.build(endpointId, NAMESPACE, NAME_CONTROL,
{
type: 'move',
direction: direction,
duration: duration,
speed: speed
});
const speechOutput = (direction === "brake")
? "Applying brake"
: `${direction} ${duration} seconds at ${speed} percent speed`;
return handlerInput.responseBuilder
.speak(speechOutput)
.reprompt("awaiting command")
.addDirective(directive)
.getResponse();
}
};
// Construct and send a custom directive to the connected gadget with data from
// the SetCommandIntent request.
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?")
.reprompt("What was that again?").getResponse();
}
const attributesManager = handlerInput.attributesManager;
let endpointId = attributesManager.getSessionAttributes().endpointId || [];
let speed = attributesManager.getSessionAttributes().speed || "50";
// Construct the directive with the payload containing the move parameters
let directive = Util.build(endpointId, NAMESPACE, NAME_CONTROL,
{
type: 'command',
command: command,
speed: speed
});
return handlerInput.responseBuilder
.speak(`command ${command} activated`)
.reprompt("awaiting command")
.addDirective(directive)
.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,
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();
MusicBox
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
# 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 backward']
LEFT = ['left', 'go left']
RIGHT = ['right', 'go right']
STOP = ['stop', 'brake']
class Command(Enum):
"""
The list of preset commands and their invocation variation.
These variations correspond to the skill slot values.
"""
MOVE_CIRCLE = ['circle', 'spin']
MOVE_SQUARE = ['square']
PATROL = ['patrol', 'guard mode', 'sentry mode']
FIRE_ONE = ['cannon', '1 shot', 'one shot']
FIRE_ALL = ['all shot']
class MindstormsGadget(AlexaGadget):
"""
A Mindstorms gadget that performs movement based on voice commands.
Two types of commands are supported, directional movement and preset.
"""
def __init__(self):
"""
Performs Alexa Gadget initialization routines and ev3dev resource allocation.
"""
super().__init__()
# Gadget state
self.patrol_mode = False
# Ev3dev initialization
self.leds = Leds()
self.sound = Sound()
self.drive = MoveTank(OUTPUT_B, OUTPUT_C)
self.weapon = MediumMotor(OUTPUT_A)
# Start threads
threading.Thread(target=self._patrol_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.MOVE_CIRCLE.value:
self.drive.on_for_seconds(SpeedPercent(int(speed)), SpeedPercent(5), 12)
if command in Command.MOVE_SQUARE.value:
for i in range(4):
self._move("right", 2, speed, is_blocking=True)
if command in Command.PATROL.value:
# Set patrol mode to resume patrol thread processing
self.patrol_mode = True
if command in Command.FIRE_ONE.value:
self.weapon.on_for_rotations(SpeedPercent(100), 3)
if command in Command.FIRE_ALL.value:
self.weapon.on_for_rotations(SpeedPercent(100), 10)
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 _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(1, 5)
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")
{
"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",
"play christmas music"
]
},
{
"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",
"move in a {Command}",
"fire {Command}",
"activate {Command}"
]
}
],
"types": [
{
"name": "DirectionType",
"values": [
{
"name": {
"value": "brake"
}
},
{
"name": {
"value": "go backward"
}
},
{
"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": "circle"
}
},
{
"name": {
"value": "square"
}
},
{
"name": {
"value": "patrol"
}
},
{
"name": {
"value": "cannon"
}
},
{
"name": {
"value": "all shot"
}
},
{
"name": {
"value": "one shot"
}
}
]
}
]
}
}
}
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