Capacitive Touch Baby Mobile

Baby Mobile

I made a fun, interactive, baby mobile! I noticed that most baby mobiles were made to be played with by touching it. However, very few mobiles responded to the touch. I created this mobile to light up in the same color as the fish that the person touched. Additionally, various different beach sounds play when each fish is touched. Enjoy!

• Various colors of 1/8in acrylic (pink, purple, crimson, orange, dark green, light green, teal, navy, yellow)
• Copper tape
• Conductive thread
• LED light strip
• Raspberry Pi Pico W (with headers and a breadboard)
• STEMMA QT / Qwiic JST SH 4-pin to Premium Male Headers Cable
• Adafruit MPR121 12-Key Capacitive Touch Sensor Gator Breakout
• Aligator clips
• Speaker
• 1/4in Baltic Birch
• Wire
• Double-sided tape
• Superglue
• Laser cutter
• Laptop
• Adobe
• Circuit python 

Laser-cut two acrylic boxes

• One large box with no front or back panel
• Make 12 small holes on the top of the box for each of the threads to go through
• Make a small rectangular hole in the back for the LED strip wires to go through
• One small box with no bottom
• For the top of the box to hide the wires
• Box Generator

Laser cut a ring out of thick wood and attach wire to the ring so it can rotate

• Measure the LED strip and make the circle's circumference the same length as the strip using the equation 2(pi)(r) and finding r
• Wrap wire around 4 points of the ring so that it is stable

Laser-cut fish in different colors

Apply copper tape to the edges of each fish

Glue conductive thread to the top of the fish

• Make sure that the copper tape is touching the conductive wire

Attach the ring and strings to the large box

• Using the 12 holes, thread each of the strings through each of their respective holes corresponding with the touch pad and lights
• Use the last 3 holes to secure the ring to the box by threading the wires through

Wire up touchpad, speaker, and LED strip to the breadboard

• Use the wiring diagrams above

Attach the fish to the ring by wrapping the string around the ring and tape the LED strip to the ring with double-sided tape

Record the beach sounds

• Record the beach sounds using audacity and save them to a file on the Rasberry Pi Pico W

Code!

• Here are some pictures of my code
• Here is my code:

#baby mobile

import board, time, neopixel

import adafruit_mpr121, digitalio, audiomixer, audiocore

from adafruit_debouncer import Button

from audiopwmio import PWMAudioOut as AudioOut

from audiocore import WaveFile

audio = AudioOut(board.GP15)

BLACK = (0, 0, 0)

PINK = (255,90,100)

MAGENTA = (199,21,193)

CRIMSON = (250,50,53)

ORANGE = (255, 40, 0)

DGREEN = (0,250,0)

LGREEN = (21,250,52)

TEAL = (0, 255, 120)

NAVY = (32,42,200)

YELLOW = (255,233,0)

# We often use these colors, but be sure to check colors used when taking exams

colors = [PINK, MAGENTA, CRIMSON, ORANGE, DGREEN, LGREEN, TEAL, NAVY, YELLOW, BLACK, BLACK, BLACK]

strip = neopixel.NeoPixel(board.GP16, 30)

i2c = board.STEMMA_I2C()

touch_pad = adafruit_mpr121.MPR121(i2c)

pads = []

for t_pad in touch_pad:

  pads.append(Button(t_pad, value_when_pressed=True))

def play_sound(filename):

  with open(path + filename, "rb") as wave_file:

    wave = WaveFile(wave_file)

    audio.play(wave)

    while audio.playing:

      pass

#make list of songs/noises for the path

path = "beach-sounds/"

beats = ["dolphin.wav", "dripping-water1.wav", "general-beach1.wav",

"orca1.wav", "seagull1.wav", "sipping-cold-drink1.wav", "water-drop1.wav",

"wave-crash1.wav", "wind1.wav", "wind1.wav", "wind1.wav", "wind1.wav"

]

num_voices = len(beats)

mixer = audiomixer.Mixer(voice_count = num_voices, sample_rate = 8000, channel_count=1, bits_per_sample=16, samples_signed=True)

audio.play(mixer)

for i in range(len(beats)):

  wave = audiocore.WaveFile(open(path+beats[i],"rb"))

  mixer.voice[i].play(wave, loop=True )

  mixer.voice[i].level = 0.0

time.sleep(1.0)

strip.fill(BLACK)

while True:

  #touched = False

  for i in range(len(pads)):

    pads[i].update()

    if pads[i].pressed:

      strip.fill(colors[i])

      mixer.voice[i].level = 0.5

      #print({i})

    if pads[i].released:

      strip.fill(BLACK)

      mixer.voice[i].level = 0.0

Secure the small box on top of the larger box to keep wires compacted

Finishing touches

• Tape extra wires down
• Secure speaker to the large box