Raspberry Pi Lessons

Topic 1

Raspberry Pi Setup

Cool, you got your Raspberry Pi. Now what?

There are wealth of information and projects you can find on the web. And you can always start with the official Raspberry Pi Documentation.

For now, let's get it started! You can either use a NOOBS sd card, or download one image to load on to a sd card to install the OS. At least for the first time setup, we suggest you have the following equipment ready:

• Need a computer to burn OS image to a SD card, if you are not using NOOBS
• TV or monitor with HDMI port, HDMI cable
• USB keyboard and mouse
• 5V 2A Micro USB power supply

After first time login and setup some basics, you can connect to Raspberry Pi using other simpler approaches that do not require monitor, nor USB keyboard/mouse. The first thing is to enable SSH and Serial by running raspi-config.

Notes

1. Load OS image to SD Card, using dd command:
   

   sudo dd bs=4m if=2016-11-25-raspbian-jessie.img of=/dev/rdiskN

2. Connecting to Raspberry Pi from computer directly using Ethernet cable. If you have a Macbook, you can access it with hostname: raspberrypi.local

   ssh pi@raspberrypi.local, then login with default password: raspberry

3. Connecting to Raspberry Pi using USB-TTL console. You can find instruction on: adafruit learning

Shrink SD card image for backup

Reference: Shrink using GParted on Ubuntu, or Resizing an image.
Here is my outline by doing on a Ubuntu box:

1. Find out the SD card mount: df -h
2. sudo gparted
3. Select the right disk for SD card, such as /dev/sdc on the up-right corner
4. Unmount the large partition, and resize it to a little bit larger than necessary
5. Create shrinked disk image with dd.

    
       sudo dd if=/dev/sdc of=/home/USERNAME/shrink_image_name.img bs=block_size count=block_count.
       For example, if you shrink the space to 3.6G, you can use block_size=4M and block_count=900, 4M x 900 = 3600M
   

6. On file explorer, eject the SD card and pull it out

Restore backup image

Be very very careful with next command, you need to be definitely, positively sure that "/dev/diskN" is the SD card where you want to put raspberry pi, replace "diskN" with actual disk number. If you are not sure, just don't do it, and wait until we meet next time. You could run the risk of wiping out your own computer!!
On Macbook:

    diskutil list   // to find out the disk number N of your SD card
    diskutil unmountDisk diskN
    sudo dd bs=4m if=downloaded_image_file of=/dev/rdiskN

In order to get into Raspberry Pi headless, please add this two files under /boot directory (usually /Volumes/boot on Mac)

1. To enable SSH by putting a file named "ssh", with any text content
2. Add a wpa_supplicant.conf, to connect to your network. File content as follow:

   # /etc/wpa_supplicant/wpa_supplicant.conf
   ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
   update_config=1
   
   network={
     ssid="your_wifi_ssid"
     psk="your_wifi_passwd"
     key_mgmt=WPA-PSK
   }    
   

Topic 3

Automatically get Raspberry Pi IP Address

1. Install email program: mutt

   sudo apt-get install mutt
   

2. Configure basic .muttrc for use with Gmail SMTP to send email, under /home/pi and /root

   set smtp_url="smtp://your_gmail_account@smtp.gmail.com:587/"
   set smtp_pass="your_gmail_password"
   set from="your_gmail_account@gmail.com"
   set realname="Your Name"
   

3. Create a script to send IP address to a mobile phone in text message. Let's call it "notifyIpAddress.sh"

   #!/bin/bash
   # Email-to-SMS Gateways
   # number@txt.att.net / @vtext.com / @messaging.sprintpcs.com / @itelcel.com
   
   HOSTNAME=`hostname`
   # EMAIL=PHONENUMBER@txt.att.net
   # EMAIL=1234567890@vtext.com
   
   ETH=`ifconfig eth0 | grep inet | awk '{print $2}' | sed 's/addr://'`
   WLAN=`ifconfig wlan0 | grep inet | awk '{print $2}' | sed 's/addr://'`
   
   echo "eth0 ip: $ETH, wlan0 ip: $WLAN" | mutt -s "$HOSTNAME ip:" $EMAIL > /dev/null
   

   Make sure to set the script executable: chmod +x notifyIpAddress.sh
4. Add a line to call this script in /etc/network/interfaces file, immediately under wlan0 section.

   ## trigger notifyOnStartup script to send out notification
   post-up /home/pi/notifyIpAddress.sh &
   

Topic 5

vi or vim editor

Reference to vi cheatsheet for beginner

A more comprehensive reference: vi editor tutorials

Topic 7

Sonic Pi - have fun programing with music

Use VNC to gain access to Raspberry Pi GUI mode, then start Sonic Pi, by going to "Raspberry" icon -> "Programming" -> "Sonic Pi" to bring up Sonic Pi application.

Reference materials:

1. The source
2. Sonic Pi Tutorial on github
3. Sonic Pi on Raspberry Pi Learning Resources

Please make a piece of music at home, and we will share during next class.

Topic 9

Voice Control - using AVS, AWS IoT and Lambda

Download "Reverb" app, which acts as Amazon Echo device. Also download "Alexa" app, so you can manage Alexa Skill Kit (ASK).

Reference materials:

1. Some winning entries on Internet of Voice Control contests
2. A simple example of Dogfeeder controlled by Alexa Skill Kit: DogFeeder
3. Alexa AVS sample projects

Develop a ASK skill for home automation.