Category: Raspberry Pi

[RaspPi] Raspberry Pi and the ili9341 Display

https://www.youtube.com/watch?v=cEcIem6R4aQ

1.) Enable SPI
# remove or comment out the spi blacklist line
sudo nano /etc/modprobe.d/raspi-blacklist.conf

2.) Install
a) FBTFT drivers as loadable modules
sudo REPO_URI=https://github.com/notro/rpi-firmware rpi-update
sudo shutdown -r now

OR

b) FBTFT drivers built into the kernel proper
sudo REPO_URI=https://github.com/notro/rpi-firmware BRANCH=builtin rpi-update
sudo shutdown -r now

3.) Install the frame buffer driver (as root):
apt-get install xserver-xorg-video-fbdev

4.) Configure frame buffer driver:
sudo vi /usr/share/X11/xorg.conf.d/99-fbdev.conf
Section "Device"
Identifier "myfb"
Driver "fbdev"
Option "fbdev" "/dev/fb1"
EndSection

5.) add Autostart:
( the gpios= Pins need to be changed to YOUR specification and connection! )
sudo vi /etc/modules
fbtft_device custom name=tm022hdh26 gpios=reset:25,led:23,dc:24 rotate=90 bgr=1
#on my selfbuild shield
#from usb -> sd card laengs
#fbtft_device custom name=tm022hdh26 gpios=reset:25,led:23,dc:24 rotate=180 bgr=1
#from cinch -> hdmi quer
#fbtft_device custom name=tm022hdh26 gpios=reset:25,led:23,dc:24 rotate=270 bgr=1

6.) add Auto login:
sudo vi /etc/inittab
#1:2345:respawn:/sbin/getty --noclear 38400 tty1
1:2345:respawn:/bin/login -f pi tty1 /dev/tty1 2>&1

7.) add Autostart X:
sudo vi /etc/rc.local
su -l pi -c "env FRAMEBUFFER=/dev/fb1 startx &"

8.) Console at boot
Add kernel argument to file /boot/cmdline.txt
fbcon=map:10

Infos taken from:
https://github.com/notro/fbtft/wiki#install
http://marcosgildavid.blogspot.de/2014/02/getting-ili9341-spi-screen-working-on.html

Video was played with this worm-of-a-command-string:
sudo mplayer -nolirc -vo fbdev2:/dev/fb1 -fs -x 320 -y 240 -zoom -framedrop -lavdopts lowres=1:fast:skiploopfilter=all ~/BadApple.avi

[RaspPi] Really poor mans DS18B20 Temperature Sensor

As I had to quickly come up with two DS18B20 Sensors for the Raspberry Pi, I decided to built them "quick and dirty" without any breadboard. It is not the most beautiful nor the best way, but it works out quite well. With one exception: It seems like the sensor is too near to the Pi and picks up heat from it :/. Anyway, here are some photos:

2014-03-24 15.22.32
That is how it would look like later.

2014-03-24 15.26.00
Adding some female header to the base. We need 5 Pins for that. The first pin is going to be connected to 3,3V, the fourth to the GPIO Pin 4 and the fifth to ground. So just cut the pins 2 and 3 from that header.

2014-03-24 15.26.21
Add an resistor to pull the Data Pin high to 3,3V. You should use an 4,7k Ohm, but anything between 4,7k - 10k Ohm should work out. I used an 10k Ohm here.

2014-03-24 15.27.08
Solder the two pins of the resistor to Pin 1 and Pin 4. Do NOT short with Pin 5!

2014-03-24 15.27.48
Add some silver wire to the fifth Pin.

2014-03-24 15.31.24
Solder the DS18B20 to the Pins. Watch out for the curved side of the Sensor, it has to face upwards!

2014-03-25 07.49.59
I choose to secure the whole sensor against short circuits and stuff with hot glue. Looks ugly, but does the trick.

2014-03-25 07.50.28
Last thing is installing the sensor in the left upper corner of the GPIO Pins of your Raspberry Pi.

After booting you have to activate the One Wire protocol like this:
sudo modprobe w1-gpio
sudo modprobe w1-therm

Then you can read your sensor by using this command:
cat /sys/bus/w1/devices/28*/w1_slave

If you want to get your reading nicely formatted, you should install bc with
sudo apt-get install bc

and use this code:
echo "`cat /sys/bus/w1/devices/28*/w1_slave | grep t | cut -d= -f2`/1000" | bc -l | awk '{printf "%.2f \n", $1}'

[RaspPi] OpenWRT Trunk with latest Raspberry Pi 3.10.32+ #648 Kernel – as Image download

As a lot of people asked for the OpenWRT / Raspberry Pi Images, I decided to make a new version which replaces the old one from this post ([RaspPi] OpenWRT Trunk with latest Raspberry Pi 3.10.18+ #585 Kernel – as Image download).

That said, the rules haven't changed:
- It is the trunk version of OpenWRT, injected with the latest Raspberry Pi Kernel
- opkg list does contain the current stable package list for the OpenWRT RPi port of the latest stable release and will work out of the box (opkg update, opkg install..) Most packages like apache should work out of the box – but kernel moduls could/will probably fail. I won’t build an package mirror and won’t build packages because of limitied time. Sorry!
- Other than the normal behavior, the RPi does use DHCP to get its IP Adress. To connect for the first time, use nmap to find your RPi in your network. (Then connect via telnet, set an password with passwd and you’re good to use SSH finally!)
- The main partition size has been changed from 48 MB to 64 MB – giving you additional space

You can just download and use the (7zip-ed) image here: rpi_openwrt_2.7z [ 6.1 MB ]

I WON'T BUILD PACKAGES!
This is for the fact that I neither got enough time, nor CPU power at hand.
Sorry :(!

[RaspPi] OpenWRT Trunk with latest Raspberry Pi 3.10.18+ #585 Kernel - as Image download

THIS POST IS OUTDATED! A NEW IMAGE HAS BEEN POSTED! PLEASE USE THE SEARCH FUNCTION TO FIND THE LATEST VERSION!

As I found out that the old tutorials weren't helpful and either the OpenWRT Trunk OR the Raspberry Pi Kernel broke the build process (you can still build it successfully, but you won't be able to use the RPi after boot!) - I sat down and found an new way. This time I don't let the kernel build by the OpenWRT enviroment, but insert an healthy and prebuilt one by the RPi Team ;)!

You can just download and use the (7zip-ed) image here: rpi_openwrt.7z [ 6.1 MB ]

There are several changes to the normal version:
- opkg list does contain the current stable package list for the OpenWRT RPi port of the latest stable release and will work out of the box (opkg update, opkg install..) Most packages like apache should work out of the box - but kernel moduls could/will probably fail. I won't build an package mirror and won't build packages because of limitied time. Sorry!
- Other than the normal behavior, the RPi does use DHCP to get its IP Adress. To connect for the first time, use nmap to find your RPi in your network. (Then connect via telnet, set an password with passwd and you're good to use SSH finally!)
- The main partition size has been changed from 48 MB to 64 MB - giving you additional space

All the best,

Nico

elektor Live 2013

You can find my slides from the elektor Live 2013, Raspberry Pi 101 Workshop here: elektor_RPi_2013_Maas.pdf [ 6,1 MB ]

The handout or "cheat-sheet" can be downloaded here: elektor_RPi_2013_Maas_Cheat_Sheet.pdf [ 0,4 MB ]

... and finally, you find the Sourcecode of the Sample Projects here: elektor_RPi_2013_Maas_Sourcecode.zip [ 0,03 MB ]

Videorecording of the talk can be found here