Hamster walkie talkies

Make a pair (or army) of ridiculous toy hamsters that can send/receive voice messages from anywhere in the world using MQTT. Touch his hand and record and send a message to other hamsters.

These hamsters are running the hardware using only 100% Javascript and I think that's useless and also super cool. 😎

They recognize touch, turn on a mic, send your voice in a Buffer as array of bytes over MQTT to another hamster many many miles away from you all in JavaScript only!

Be prepared to debug hamsters!

Proof of concept	Debugging
hamster.mp4	IMG_4829.MOV

Materials:

• Raspberry Pi Zero W
• Talking hamster (amazon) - note this specific hamster has the hackable board w/o integrated piezo mic!
• Adafruit I2S MEMS microphone
• Adafruit MPR121 Capacitive touch breakout
• Adafruit NeoPixel PCB button
• 270Ω Resistor
• 150Ω Resistor
• 2.2kΩ Resistor
• 100Ω Resistor
• 2 x 10µF electrolytic capacitor
• 33nF ceramic capacitor
• Proto board
• Shrink tubing
• Heat glue gun
• Soldering iron
• conductive thread
• Heat gun (optional)
• wiring
• stemma QT to male connector
• male jumper cables (to connect things to the headers on pi)

Setup hamster:

• Stitch a conductive thread area on his hand to trigger recording and sending a message!
• Assemble circuitry as shown above.
• Remove hamster skin by cutting ziptie at bottom.
• Insert circuit into hamster and file plastic case

Setup pi zero w:

• format sd card - pi formatter

• install git

• install nvm

• install node arm (https://gist.github.com/traumverloren/7b1140e6c438988df755d047e1e98a7b)

• enable i2c & spi in sudo raspi-config (Interface options menu)

• install i2s mems mic (https://learn.adafruit.com/adafruit-i2s-mems-microphone-breakout/raspberry-pi-wiring-test)

• check working: arecord -l

• enable autoloading of i2c: https://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/configuring-i2c#installing-kernel-support-with-raspi-config-5-4

• sudo apt-get install i2c-tools

• check i2c working: i2cdetect -y 1

• setup i2s audio output over pwm pins:

  • sudo nano /boot/config.txt
  • add: dtoverlay=audremap, pins_12_13
  • then sudo reboot now
  • check working: aplay -l
  • if necessary, update to use audio over headphones in sudo raspi-config

• git clone this repo

• add .env w/ secrets

• npm i

• add the following to/boot/config.txt for neopixels to work properly:

  # Fix for running neopixels on SPI (GPIO 10)
  core_freq=250

• update so can run node/npm with sudo (needed for neopixels):

  sudo ln -s "$NVM_DIR/versions/node/$(nvm version)/bin/node" "/usr/local/bin/node"
  sudo ln -s "$NVM_DIR/versions/node/$(nvm version)/bin/npm" "/usr/local/bin/npm"

• run npm start

• setup pm2:

  npm i -g pm2
  pm2 startup # setup pm2 to run at boot
  sudo env PATH=$PATH:/home/pi/.nvm/versions/node/v18.16.0/bin /home/pi/.nvm/versions/node/v18.16.0/lib/node_modules/pm2/bin/pm2 startup systemd -u pi --hp /home/pi # run command returned from above
  pm2 start npm --name "YOURNAMEHERE" -- start
  pm2 save
  pm2 logs

Useful links:

• https://pinout.xyz/pinout/pin36_gpio16
• https://pt.pinout.xyz/pinout/pin38_gpio20
• https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/overview
• https://www.tinkernut.com/adding-audio-output-raspberry-pi-zero-tinkernut-workbench/
• https://forums.raspberrypi.com/viewtopic.php?p=1936253#p1936253
• https://www.instructables.com/Talking-Hamster-Hack/
• https://www.oodlestechnologies.com/blogs/recording-audio-in-raspberry-pi-3-using-nodejs/