pi

Raspberry Pi and Crossbar.io IoT Starterkit Cookbook

This part of the IoT Cookbook provides information, howtos and components for the Raspberry Pi and the Crossbar.io IoT Starterkit.

Enable SSH

Use sudo raspi-config to enable remote SSH access to the Pi - see here.

Then add your public key for password-less login:

ssh [email protected]
mkdir ~/.ssh
chmod 700 ~/.ssh
exit
scp /home/oberstet/.ssh/id_rsa.pub [email protected]:~/.ssh/authorized_keys

Update the system

To update the system:

sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get autoremove
sudo reboot

Useful tools

To install some useful tools:

sudo apt-get install -y wget curl vim git htop screen tmux fio glances

Configure Keyboard

The official docs don't work for me, but this does:

sudo dpkg-reconfigure keyboard-configuration

Configure Hardware

SPI and I2C

Enable SPI and I2C by running

sudo raspi-config

Go to "Interfacing Options" and make SPI and I2C are enabled.

Disable Onboard Audio

The onboard Pi audio and the Neopixels boths use PCM hardware and can't be used at the same time. See here. To disable the onboard audio:

sudo sh -c 'echo "blacklist snd_bcm2835" > /etc/modprobe.d/snd-blacklist.conf'

Check

To check the hardware kernel support modules loaded:

pi@raspberrypi:~ $ lsmod
Module                  Size  Used by
bnep                   12051  2
hci_uart               19956  1
btbcm                   7916  1 hci_uart
bluetooth             365511  22 hci_uart,bnep,btbcm
brcmfmac              222874  0
brcmutil                9092  1 brcmfmac
cfg80211              543027  1 brcmfmac
rfkill                 20851  4 bluetooth,cfg80211
spidev                  7373  0
bcm2835_gpiomem         3940  0
spi_bcm2835             7596  0
i2c_bcm2835             7167  0
evdev                  12423  2
uio_pdrv_genirq         3923  0
uio                    10204  1 uio_pdrv_genirq
fixed                   3285  0
i2c_dev                 6913  0
ipv6                  406279  30

Installing Docker

The components we provide are run inside Docker containers.

To install Docker, do

curl -sSL https://get.docker.com | sh

You also need to be able to run Docker without superuser rights (sudo) which can be done like so

sudo usermod -aG docker pi

Remember to log back in & out or reboot afterwards for this to take effect.

Pull some images:

docker pull crossbario/crossbar-armhf
docker pull crossbario/autobahn-js-armhf
docker pull crossbario/autobahn-python-armhf

Check Serial

To get the Pis serial number:

pi@raspberrypi:~ $ cat /proc/cpuinfo | grep Serial
Serial      : 000000005b0966b4

Clone the IoT Cookbook repo

cd ~
git clone https://github.com/crossbario/iotcookbook.git

Pi Setup: Wi-Fi

You'll often run your Pi headless (controlling it via SSH rather than mouse, keyboard and a monitor).

The following is how you set up Wi-Fi in this case. Additionally, this allows setting up Wi-Fi networks that are not presently in range, and to copy a Wi-Fi configuration across multiple devices.

SSH into the Pi and edit the following file:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

For example, here is mine (passwords stripped):

pi@raspberrypi:~ $ sudo cat /etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
    id_str="office"
    ssid="ap-office"
    psk="********"
    priority=5
}

network={
    id_str="home"
    ssid="ap-home"
    psk="********"
    priority=3
}

network={
    id_str="mobile"
    ssid="ap-mobile"
    psk="********"
    priority=1
}

You can have multiple networks defined, and have priorities on networks as well (when multiple configured networks are in reach). Switching between networks only works for me when rebooting! There are also recipes for making that automatic using some scripts, eg here - I haven't explored that path yet.

To scan for Wifi networks in reach:

sudo iwlist wlan0 scan

To restart Wifi (without reboot):

sudo ifdown wlan0
sudo ifup wlan0

To get the current Wifi configuration of the Wifi interface:

ifconfig wlan0

To find a Pi on some network:

nmap 192.168.43.*

Eg given above, this Pi (MAC F4:F2:6D:14:1B:56) will join one of the Wifi network (depending on which one is in reach):

• office: 192.168.1.142
• mobile: 192.168.43.105
• home: 192.168.55.104

Image creation and cloning

The following describes how to clone a SD card, eg for the Crossbar.io IoT Starterkit.

You will need these tools (on your host, not the Pi):

sudo apt install -y pv pigz

Determine your SD card device:

sudo fdisk -l

WARNING: you must be absolutely positive on the device! dd is dangerous - it will happily overwrite your main disk if you ask it to.

Insert source SD card and copy the image to a local file (this take roughly 8 minutes on my box):

sudo dd if=/dev/sdb bs=1M | pv | pigz --fast > cb-iot-starterkit.img.gz

To copy the image to a target SD card (a 16GB):

sudo sh -c 'pigz -dc cb-iot-starterkit.img.gz | pv -s 15931539456 | dd of=/dev/sdb bs=1M' && sudo sync

IMPORTANT: do NOT forget sudo sync to actually flush all bytes to the SD card and wait until this is finished!

To upload the image to S3:

aws s3 cp cb-iot-starterkit.img.gz s3://package.crossbar.io/