romanpavelka.cz

Personal web page of Roman Pavelka, software engineer

Raspberry Pi tips and tricks

My scripts often used on rpi are available in this repo.

Deployment with Raspbian

passwd
sudo su
passwd

# enlarge card, set hostname and restart
raspi-config

sudo su
cp /usr/share/zoneinfo/Europe/Prague /etc/localtime
aptitude remove wolfram-engine # more than 450 MB freed...
aptitude install htop screen
screen
rpi-update
aptitude update
aptitude full-upgrade

aptitude install python-matplotlib image-magick autossh -y
ssh-keygen -t rsa

Set wifi and dhcp on Raspbian

Your /etc/wpa_supplicant/wpa_supplicant.conf should look like this:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
  ssid="NETWORK_SSID"
  psk="NETWORK_PASSWORD"
  proto=RSN
  key_mgmt=WPA-PSK
  pairwise=CCMP
  auth_alg=OPEN
}

and your /etc/network/interfaces

auto lo

iface lo inet loopback
iface eth0 inet dhcp

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
wireless-power off

iface default inet dhcp

Then I have little script for logging wifi status and restarting it when needed. (check_net.sh is available also here)

#!/bin/bash

DATE=`date +%Y-%m-%dT%H:%M:%S`
FAILS=/home/pi/care/fails

# terminate on ping success:
ping romanpavelka.cz -q -c 2 -w 10 > /dev/null && exit 0

# if not terminated, ping google DNS, mark romanpavelka problem on success and exit:
ping 8.8.8.8 -q -c 2 -w 10 > /dev/null && echo $DATE failed to reach rp >> $FAILS && exit 0

# if not terminated, ping router and mark on success
# external network problem, on unsuccess internal
ping 192.168.0.1 -q -c 2 -w 10 > /dev/null \
&& echo $DATE failed to reach google DNS >> $FAILS && exit 0\
|| echo $DATE failed to reach router >> $FAILS

# else try to reset the wifi adapter
sudo ifdown wlan0
sudo killall -q dhclient
sudo killall -q wpa_supplicant
sleep 5
sudo ifup --force wlan0

I use cron calling it every five minutes.

Modules building

Firts you need headers of your kernel, the simplest way to get them is the rpi-source script.

sudo wget https://raw.githubusercontent.com/notro/rpi-source/master/rpi-source -O /usr/bin/rpi-source
sudo chmod +x /usr/bin/rpi-source
/usr/bin/rpi-source -q --tag-update

This is nice cheap 802.11b/g/n, up to 150 Mbit/s, USB2.0 wifi adapter.

With 1A 5V supply I didn’t get any problems supplying this stick and webcam directly from Pi.

Install kernel headers as explained above and compile and install RTL8188EU driver from [https://github.com/lwfinger/rtl8188eu].

Nginx instead of Apache

sudo su
aptitude install nginx -y && aptitude install php5-fpm -y
nano /etc/nginx/sites-enabled/default # I like to set document root to /var/www
nano /etc/php5/fpm/php.ini            # set cgi.fix_pathinfo=0
service php5-fpm restart
service nginx restart

Source: [http://elinux.org/RPi_Nginx_Webserver]

To allow directory listings, set in site configuration file (that linked in /etc/nginx/sites-enabled):

        location /somedir {
               autoindex on;
        }

here the root path / presents root directory of the webpage as specified in /etc/nginx/sites-enabled/default.

Source: [https://www.digitalocean.com/community/tutorials/how-to-set-up-http-authentication-with-nginx-on-ubuntu-12-10]

Roman Pavelka,