Asha Seshan
Created December 19, 2019 © CC BY-NC-SA

Baby Crib Mobile

A new mother can now soothe her baby back to sleep with help from Alexa and a customizable LEGO MINDSTORMS mobile hanging over a crib.

BeginnerFull instructions provided1 hour48

Things used in this project

Hardware components

EV3 Programming Brick / Kit
LEGO MindStorms EV3 Programming Brick / Kit
×1
Echo Show (2nd Gen)
Amazon Alexa Echo Show (2nd Gen)
×1

Software apps and online services

Alexa Voice Service
Amazon Alexa Alexa Voice Service
ev3dev

Story

Read more

Custom parts and enclosures

Baby Mobile Build Instructions

Use this to build the mobile

Code

Code for EV3 and Alexa Skill

Python
This is the python code that runs on the EV3 brick to move the mobile in response to the Alexa music.
#!/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 threading
import random

from agt import AlexaGadget

from ev3dev2.led import Leds
from ev3dev2.sound import Sound
from ev3dev2.motor import OUTPUT_A, OUTPUT_B, OUTPUT_C, OUTPUT_D, LargeMotor

# 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 MindstormsGadget(AlexaGadget):
    """
    A Mindstorms gadget that performs movement in sync with music tempo.
    """

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

        # Ev3dev initialization
        self.leds = Leds()
        self.sound = Sound()
        self.left_motor = LargeMotor(OUTPUT_A)
        self.right_motor = LargeMotor(OUTPUT_B)
        self.top_motor = LargeMotor(OUTPUT_C)
        self.bottom_motor = LargeMotor(OUTPUT_D)

        # Gadget states
        self.bpm = 0
        self.trigger_bpm = "off"

    def on_connected(self, device_addr):
        """
        Gadget connected to the paired Echo device.
        :param friendly_name: the friendly name of the gadget that has connected to the echo device
        """
        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 friendly_name: the friendly name of the gadget that has disconnected from the echo device
        """
        self.leds.set_color("LEFT", "BLACK")
        self.leds.set_color("RIGHT", "BLACK")
        logger.info("{} disconnected from Echo device".format(self.friendly_name))

    def on_alexa_gadget_musicdata_tempo(self, directive):
        """
        Provides the music tempo of the song currently playing on the Echo device.
        :param directive: the music data directive containing the beat per minute value
        """
        tempo_data = directive.payload.tempoData
        for tempo in tempo_data:

            print("tempo value: {}".format(tempo.value), file=sys.stderr)
            if tempo.value > 0:
                # dance pose
                self.right_motor.run_timed(speed_sp=750, time_sp=2500)
                self.left_motor.run_timed(speed_sp=-750, time_sp=2500)
                self.top_motor.run_timed(speed_sp=750, time_sp=2500)
                self.bottom_motor.run_timed(speed_sp=-750, time_sp=2500)
                self.leds.set_color("LEFT", "GREEN")
                self.leds.set_color("RIGHT", "GREEN")
                time.sleep(3)
                # starts the dance loop
                self.trigger_bpm = "on"
                threading.Thread(target=self._dance_loop, args=(tempo.value,)).start()

            elif tempo.value == 0:
                # stops the dance loop
                self.trigger_bpm = "off"
                self.leds.set_color("LEFT", "BLACK")
                self.leds.set_color("RIGHT", "BLACK")

    def _dance_loop(self, bpm):
        """
        Perform motor movement in sync with the beat per minute value from tempo data.
        :param bpm: beat per minute from AGT
        """
        color_list = ["GREEN", "RED", "AMBER", "YELLOW"]
        led_color = random.choice(color_list)
        motor_speed = 2*bpm
        milli_per_beat = min(8000, (round(60000 / bpm)) * 4.65)
        print("Adjusted milli_per_beat: {}".format(milli_per_beat), file=sys.stderr)
        while self.trigger_bpm == "on":

            # Alternate led color and motor direction
            led_color = "BLACK" if led_color != "BLACK" else random.choice(color_list)
            motor_speed = -motor_speed

            self.leds.set_color("LEFT", led_color)
            self.leds.set_color("RIGHT", led_color)
            self.right_motor.run_timed(speed_sp=motor_speed, time_sp=int(milli_per_beat))
            self.top_motor.run_timed(speed_sp=motor_speed, time_sp=int(milli_per_beat))
            self.bottom_motor.run_timed(speed_sp=-motor_speed, time_sp=int(milli_per_beat))
            self.left_motor.run_timed(speed_sp=-motor_speed, time_sp=int(milli_per_beat))
            time.sleep(milli_per_beat / 1000)

        print("Exiting BPM process.", file=sys.stderr)


if __name__ == '__main__':

    gadget = MindstormsGadget()

    # Set LCD font and turn off blinking green 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")

Config Code for EV3 and Alexa Skill

Python
The ini file that goes along with the python code.
# 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 = FILLTHIS
alexaGadgetSecret = FILLTHIS

[GadgetCapabilities]
Alexa.Gadget.MusicData = 1.0 - tempo

Credits

Asha Seshan

Asha Seshan

1 project • 5 followers
Thanks to Seshan Brothers.

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