Node.js + Raspberry Pi = Love IBM Index Talk Notes

ibm-index-node-rpi.md

Hardware list:

• Ethernet cable
• Thunderbolt ethernet adapter
• USB power adapter
• MiFi USB cable inverter for powering RPi
• 2 x Micro USB B cables
• 2 x Micro SD Cards
• 2 x SD Card adapters
• 2 x Raspberry Pi (2s)
• Webcam
• Webcam stand thing
• Laptop
• Laptop power adapter

Talk steps:

Flash the image

• Switch to Chrome
• Show off where to download image
• Show off installation guide
• Switch to terminal
• diskutil list - note 8gb disk
• diskutil unmountDisk /dev/disk3
• Show off sudo dd bs=1m if=2017-11-29-raspbian-stretch.img of=/dev/rdisk3 conv=sync (already have this done)
• Write lite version to SD card (about 2:20)
• cd /Volumes/boot
• touch ssh
• cd ..
• diskutil unmountDisk /dev/disk3

Connect to the RPi

• Switch to the webcam
• Connect Raspberry Pi to ethernet to laptop
• Insert SD card once done writing
• Plug in power
• Switch to System Preferences
• Enable internet sharing from Wifi to Thunderbolt
• Wait for activity LED to stop flashing (about 1:20)
• Plug in ethernet cable to RPi
• Switch to a terminal
• cat /var/db/dhcpd_leases
• ssh pi@ip-from-above

Base configuration

• passwd for security
• sudo apt-get update
• Show off sudo apt-get upgrade but don't actually run
• sudo apt-get install git
• sudo dpkg-reconfigure tzdata to set timezone
  • Select Pacific-new as timezone

Install Node.js

• Talk about how apt-get repo sucks
• Talk about LTS vs latest
• curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
• sudo apt-get install nodejs
• node -v
• npm -v

Setup Johnny-Five

• mkdir index
• cd index
• npm install johnny-five raspi-io (about 3:30)
• Switch to Chrome
• Go to johnny-five.io and talk about J5
• Go to https://github.com/nebrius/raspi-io and talk about Raspi IO
• Go to pin naming wiki article and talk about pin naming
• Switch to terminal
• Explain why have to reboot
• sudo reboot
• Log back in once up

Write LED hello world

const five = require('johnny-five');
const Raspi = require('raspi-io');

const board = new Five.board({
  io: new Raspi()
});

board.on('ready', () => {
  const led = new five.Led('P1-12');
  led.blink();
});

On laptop:

rsync -avz -e ssh *.js pi@192.168.2.2:/home/pi/index

On RPi:

sudo node --inspect-brk=192.168.2.2:9229 led.js

• Change blink to pulse and talk about how J5 handles GPIO vs PWM under the hood for you

Bonus steps

• Software PWM and Raspi IO constructor options
• Show off button

const five = require('johnny-five');
const Raspi = require('raspi-io');

const board = new five.Board({
  io: new Raspi()
});

board.on('ready', () => {
  const led = new five.Led('P1-12');
  const button = new five.Button('P1-38');
  button.on('press', () => led.toggle());
});

• Show off temperature sensor

const five = require('johnny-five');
const Raspi = require('raspi-io');

const board = new five.Board({
  io: new Raspi()
});

board.on('ready', () => {
  const thermometer = new five.Thermometer({
    controller: "MCP9808"
  });

  thermometer.on("change", () => {
    console.log("Thermometer");
    console.log("  celsius      : ", thermometer.celsius);
    console.log("  fahrenheit   : ", thermometer.fahrenheit);
    console.log("  kelvin       : ", thermometer.kelvin);
    console.log("--------------------------------------");
  });
});