I am creating a GUI interface that will be using a 7" touch display with a raspberry pi 3. I want the GUI to take the place of the desktop, I do not want it displayed in a window on the desktop. any thoughts on how to do that. I have read the raspberry pi documentation to edit the rc.local script to start the application at login, but I can not figure out how to set up the python GUI with out creating a window
Your pi boots up and displays a console - just text - by running a program (getty). Then you run another application called a graphical display manager which then runs a window manager. On a pi it is usually gnome but there are many others,.. this window manager is what displays your GUI window. What you want is obviously possible, it is just that it is non-trivial to do. What you are talking about is either kiosk-mode application still running 'on the desktop' as you say but which obscures the desktop completely and does not allow you to switch or de-focus or an even more complicated JeOS like Kodi/XBMC bare metal installation running without your current window manager. Your python would have to do the job of the display manager and the window manager and it would be very, very slow.
Use a really light window manager and go kiosk mode. Or you could go with text! There are libraries eg ncurses but I'm not sure how that would work with your touch screen display.
1.
Disable graphical interface i.e. stop the desktop manager from running.
On Raspbian you can use raspiconfig to do it.
2.
Set up autologin into bash
3.
Block startx from automatically running desktop manager
4.
Add your app to be started from .bash_rc when autologin is performed.
To setup autologin first create a script called autologin in /bin directory that does:
#! /bin/bash
/bin/login -f pi
Note: pi is an user on raspbian that won't ask for password when sudo-ing.
To use the created script edit /etc/inittab:
Scroll down to where terminals are assigned and change tty1's line to be:
1:2345:respawn:/sbin/getty -n -l /bin/autologin 38400 tty1
Take care that ids are matching old tty1 settings.
Then in the user's home directory (/home/pi) add (if it's not already there) a file named ".xinitrc" containing just:
#! /bin/bash
cat
This will prevent X server from invoking desktop manager when started.
Now add in /home/pi's .bashrc your app or better a script that will run your app (at the end):
export DISPLAY=:0
/home/pi/Desktop/appstart &
startx
And appstart is:
#! /bin/bash
# Wait a second for X server to start:
sleep 1
# Now X is running and we have to switch into video terminal using chvt (change virtual terminal) command
# Graphic terminal is on Raspbian tty7
sudo chvt 7
# Start the app:
python /home/pi/Desktop/myapp/myapp.py
After all this is set up what will hapen is the following:
1.
You run Raspberry Pi and it autologins into user pi
2.
When Bash logs in it executes /home/pi/.bashrc
3.
.bashrc sets $DISPLAY variable because there are no X displays yet, runs starting script as a background job and starts X server.
4.
X server won't enter desktop manager because /home/.xinitrc will stop it step short of it.
5.
Starting script sleeps for a second to ensure that X is running and able to send graphics to tty7, switches to tty7 so that user doesn't have to do it manually, and then runs your application which will show up.
If your app is not graphical you will see only one big nothing. :D
Problems here are that you definitely should create an user just for this stuff. If your app crashes or user switches to tty1 and terminates X there he/she is in bash, logged in.
Depends on what level of security you need. You can do a lot of things to prevent abuse. For example, use fcntl to change mode tty1 is in so that it cannot receive key input any longer.
Or use some other tricks, or rearange this procedure somewhat, or ensure that tty1 runs everything in jobs with nohup, then logs out etc, etc.
Related
I made an app in Thonny that when I run it, shows a camera connected to RPI and shows the image in an interface. You can also use the keyboard to do some things in the interface, take photos, etc.
I always execute it using thonny (run button), but now, I am trying to autostart the program in python when Raspbian ends its starting (after a shutdown or reboot).
I tried to do it in 3 ways:
autostart
lxde-pi/autostart
crontab
But it doesn't work. It starts Raspbian, but nothing more. Any ideas or code to do it?
Thanks a lot.
This might be a bit late for #mash_10, but for anyone else who lands here my solution that auto fires a bash script on the home folder. To add new automatic startups I just add code to my personal bash script. This works on Buster rpi.
Details are in my answer here How to automatically launch python file once GUI has loaded on Raspbian Pixel
I'm writing a script that (basically) controls some motors from raspi gpio pins. I've been making it right for a while now, and when I boot the pi and run the program manually it works just fine. I also have a portion of the code that allows me to use my phone to connect via bluetooth and send some data to control the motors. That also works fine on a manual run of the program.
Now I am trying to make the program start automatically on boot, as this will eventually go in a larger machine (boat) and I won't be hooking a monitor etc. to it. I'm currently doing this through a cron job with the #reboot tag. Looks like this:
#This enables GPIO (as far as I know). The program fails without this command being run first.
#reboot sudo pigpiod
#This runs the python program. ampersand forks the process because it should run continuously.
#reboot python3 /home/pi/Desktop/BoatBrain.py &
#and this lets me connect my phone over bluetooth. The python program has
#a portion takes data from that connection. ampersand forks the process, which
#seems like the right thing to do, since it looks like it blocks other things.
#That is also why it is at the end of the cron table.
#reboot sudo rfcomm watch hci0 &
When I reboot, the jobs all run, and I can connect my phone, so it must have passed the line executing the python script, but the servo I have connected just jitters in place uncontrollably. Let me restate that when I take the cronjobs away and run this manually, the program works correctly with few to no jitters, so it doesn't feel like an electrical problem...
If you need any more information please let me know and I'll be happy to provide it. I have a tendency to leave things out without realizing XD
Thanks!
Did you add anything to ~/.profile? It might be why it works when you invoke the commands yourself. If so, create a file in sudo vi /etc/profile.d/servo.sh with the same couple lines you added to ~/.profile. Then the system will have those on reboot.
Also, you could put all the three commands in one shell script and just put the script in the crontab. then the script can control that they start in order. You could also have the cronjob write output to a logfile and then see what it says. Also you can check when the cron runs by looking in /var/log/syslog
Oh, also for testing, you can change #reboot to a start time like 10 * * * * and then you can get the cron working without having to reboot. Then later, change it back to #reboot to try it with reboot.
Either something is missing that your login has (.profile), the commands are starting too quickly at the same time and need to start in a controlled order or the system isn't completely ready yet, but I doubt that one.
I have a bash script that I've defined to run in startup, which runs a python script that waits for a command from another process, and when it gets it, it should open a chromium window with a certain URL.
When I run this script manually it works fine, but when the script runs from startup, I get an error (displayed in syslog):
Gtk: Can't open display
I guess that's because it's running in a startup mode so it doesn't actually have a display to "lean" on...
I was wondering if there's any way to get this work, anyway?
Thanks in advance
In your script that runs on startup try DISPLAY=:0 <command> &
To clarify DISPLAY=:0 simply sets which monitor your window opens on with 0 representing the first monitor of the local machine.
I've got this python script that opens up a VNC session through a graphical window. It sits there blocking waiting for a particular message to come in and then spawns the graphical window successfully when ran from the command prompt.
But if I place this in an Upstart .conf file so I can use it as a background service, I can see that my program receives the message to pop up a window but it does not display a graphical window.
...
exec /usr/local/bin/vncscript.py # does not display window
...
How would I go about displaying a graphical window using Upstart?
Ended up going with the solution from by setting up a .desktop file:
https://askubuntu.com/questions/107187/how-to-launch-gui-app-with-upstart-script
Initially, I started by a
export DISPLAY=0.0
...and it worked. I could then control it as a service. But as soon as I restarted the computer, it would not work as expected. Could not even stop the service after starting it. I'm not sure why it worked in the first place.
I have written a python script which waits for a keyboard input and it will run in a Raspberry Pi.
I want it to run as soon as the Raspi gets powered (without the need to log in and to type the command in order to start the script). Note that it is not a deamon, since it will interact with the user. How can I do that?
I found the instructions on this page:
http://www.akeric.com/blog/?p=1976
very helpful to achieve what you are asking. Specifically the page describes how to configure the pi to automatically log in to one of the shells and how you can then run a script as the shell starts up.
Note that when I used this approach, the pi was not exposed to the outside world, so I did not check this approach for possible security weaknesses.
belated edit since the original answer was 'link only':
including the relevant content from the link to summarize the necessary steps here in case the link falls dead:
edit inittab (e.g. using nano):
sudo nano /etc/inittab
replace this line:
1:2345:respawn:/sbin/getty 115200 tty1
with this:
1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1
This will automatically login on tty1 upon startup. Then you can start your script e.g. by including it into the .bashrc.