TFT touchscreens for the Raspberry Pi
Clicking Without Regret
This minimalist approach is good enough for simple commands. However, it is unlikely that you want to begin a restart by making a mistake. Additionally, some programs only display actual information in the console. If you start these in the graphical interface, the output would end up in an unknown bit bucket.
Therefore, the launcher uses a second PyGTK program called CommandGui.py. The program serves as a wrapper for command-line programs. Besides providing output of results, it also makes yes-or-no queries possible.
The configuration file appconfig.py is shown below. sudo reboot is started via a wrapper program. The "-i" parameter instructs the wrapper to interact with the user before executing the command (Figure 6):
Figure 6: To avoid the unintended execution of programs, interactive prompts come up as desired.
name = "Reboot" icon = "./system-reboot.png" cmd = ["CommandGui.py","-i","sudo","reboot"]
The wrapper program does even more; for example, Figure 7 shows the request for the current IP address of the computer. You will find the source codes for the wrapper together with documentation and installation guidelines on the Raspberry Pi Geek FTP site [10] and on SourceForge [11].
Figure 7: The wrapper also permits incorporation of console programs. You can see the output of ifconfig in this picture.
Conclusion
As with the Rasp Pi, the display screens presented here have only limited resources. The restrictions ensuing from 320x240 pixels can be disturbing for many uses. However, as with the Rasp Pi itself, the limited possibilities encourage the use of imagination and creativity. The Rasp Pi remains true to its origins with a small display screen that needs almost no additional electricity, and many new projects on the horizon require just a simple user interface.
Interview with Pi3g Founder Maximilian Batz
Raspberry Pi Geek: When did you get the idea of founding a company built around the Rasp Pi?
Max Batz: In mid 2012 my friend Florian and I held a Raspberry Pi in our hands for the first time. We immediately realized the potential of this small computer revolution that is still underway. For example, the company General Purpose Compute [12] is working on using the GPU as an extension to a CPU.
RPG: Pi3g has a number of very spiffy solutions like the Pi.card and the housing branding. What are you planning for the future?
MB: The next thing we want to do is to build our own housing that will make it possible to use the Rasp Pi as a small touch terminal. This would work for example with a web radio application. We would like to offer appliances based on pre-integrated Pi.cards. This could be a cam box for monitoring rooms and operating electrical switches if necessary. Then the user could remotely call up a video stream or snapshots from a smartphone.
The limited performance of the Rasp Pi is not sufficient for many applications. We are planning to alleviate these shortcomings, either with a special hardware version of the Pi based on compute modules and coprocessors, or via boosting virtualization. This approach would give the Raspberry Pi the necessary resources, and CPU-intensive applications could simply be shifted around.
RPG: The Rasp Pi is perfectly sufficient for many things but some solutions need more performance, in particular I/O. Are there plans in place to expand the offering?
MB: We have looked at other systems like Banana Pi, CubieBoard, and RiOTBoard, but these all have various disadvantages. Even when the technology is sound, a community and sample code is lacking. The Rasp Pi has an enormous advantage in this respect. Personally I consider the HummingBoard from SolidRun pretty interesting. I recommend the CuBox-I from the same company for OpenELEC. We are in the process of figuring out whether we should import this hardware into Germany from Israel, but the Raspberry Pi will remain our priority.
Figure 8: The Pi3g team with, from left, Florian Frankenberger, Max Batz, and Timo Andrews.
Infos
- Pi3g display: http://my.pi3g.com/en/quick-start/raspberry-pi-display-addon/
- Watterott display: http://www.watterott.com/index.php?page=product&info=3530
- Kernel image of Pi3g: https://github.com/entrusc/linux-lcd
- Raspbian image for the Watterott display: https://github.com/watterott/RPi-Display
- FAQs for the Pi3g display: http://my.pi3g.com/en/quick-start/raspberry-pi-display-addon/faq/
- "C-Berry Display" by Marcus Nasarek, Raspberry Pi Geek, Issue 6, pg. 70: http://www.raspberry-pi-geek.com/Archive/2014/06/Using-the-C-Berry-screen-for-graphics-output
- Adafruit 2.8-inch screen: http://www.adafruit.com/products/1770
- Adafruit Pi camera based on PyGTK: https://github.com/adafruit/adafruit-pi-cam
- PyGTK: http://www.pygtk.org
- Code for this article: ftp://ftp.linux-magazin.com/pub/listings/raspberry-pi-geek.com/07
- Pi28Apps: http://sourceforge.net/projects/pi28apps/
- Computing with a GPU: http://petewarden.com/2014/06/09/deep-learning-on-the-raspberry-pi/
The Author
Bernhard Bablok works for Allianz Managed&Operations Services SE as an SAP-HR developer. In his free time, Bernhard listens to music, enjoys hiking and biking, and he occupies himself with all subjects that have to do with Linux and object orientation.
« Previous 1 2 3 4 Next »
Buy this article as PDF
Pages: 6
(incl. VAT)
Buy Raspberry Pi Geek
US / Canada
UK / Australia
Related content
-
Display T. Box: The (second) third generation
Display T. Box is a Raspberry Pi with a touch display in a compact case. The newest version of the Box comes with revisions that include a better touch screen and more speed.
-
Testing the new Raspberry Pi touchscreen display
The new Rasp Pi display provides a compact option for viewing screen output – and it comes at a Pi-like low price of only $60.
-
Adapting to a small touchscreen monitor with PiMenu
Use PiMenu to build a menu-based graphical interface optimized for small LCD touchscreens.
-
Using the Raspberry Pi to control digital information screens
A digital information screen provides constantly updated information to viewers. All you will need to create one is a Raspberry Pi, the appropriate software, and a monitor.
-
Display T. Box is a Raspberry Pi with an integrated display
Display T. Box combines a Raspberry Pi 2 with an integrated touchscreen. The result is a complete mini-PC that can be used as soon as you supply power.
