Controlling screen brightness on pi-topCEED on Raspbian Jessie with guizero app and keyboard shortcut

I backed the pi-topCEED during the crowd funding campaign and have used it a lot since.

pi-topCEED

My kids also use it for homework and general Minecraft playing.

As I like to make things I have a number of microSD which means I regularly use it with Raspbian Jessie.

There are a couple of drawback to using Raspbian on the pi-topCEED.  The pi-topHUB doesn't shutdown the power completely leaving the backlight on and the Raspberry Pi in kind of a suspecd mode. The red LED is still on.  Also, there is no way to control the screen brightness.

Doing the usual Google to see if there was a way around this I came across this GitHub repository that looked like it would do the job.  https://github.com/rricharz/pi-top-install

It includes code to shutdown the pi-topHUB which also completely shuts down power to the display and to the Pi as well as provide a program called 'brightness' to control the screen brightness.

After following the instructions in the README.md I had the pi-topHUB shutting down correctly and if from the terminal I type brightness increase the screen brightness would go up and vice versa brightness decrease did what you'd expect.

All very good, but not very user friendly if you're running the GUI which is where I spend most of my time. 

With that in mind and having recently heard good thing about guizero (https://github.com/lawsie/guizero) which is based on tkinter and is said to make building GUI apps  in Python easier.

It looked to me like a simple app with 2 buttons [Darker] [Brighter] is all I needed so I read up a little on guizero.  Using the App using grid layout example (https://lawsie.github.io/guizero/app/) I soon has a small app that did exactly what I wanted.
Code available on Git Hub (https://github.com/winkleink/pi-top-brightness)

The program itself is quite short. Code below.  This makes 2 buttons.  Button1 and Button2.  When you press them they run the relevant system comment to change the brightness. 

from guizero import *

from subprocess import call

def brighter():

    call(["brightness", "increase"])

    

def darker():

    call(["brightness", "decrease"])

    

    

app = App(title="pi-top", height=50, width=145, layout="grid", bgcolor=None)

button1 = PushButton(app, brighter, text="Brighter", grid=[0,1])

button2 = PushButton(app, darker, text="Darker", grid=[0,0])

app.display()

Here is a video showing it working.

After a quick chmod +x  pi-top-brightness-gui.py the program was executable and so I could run it directly.

Then I added the program to the main menu under the System Tools section.

In the video you can see I have a pi-top icon.  This I took from their Twitter account (https://twitter.com/GetPiTop)  I expect they'll be OK with that as I'm adding even more branding to my pi-topCEED.

I explained in a recent post on backing up Minecraft Worlds how to add a program to the menu (http://www.winkleink.com/2016/07/minecraft-pi-backup-worlds-on-exit.html)

It's great to have a little gui app to change the brightness of the screen and even better to learn a new skill with guizero.

One thing I didn't mention is that when I rebooted the Raspberry Pi the first time after installing the programs the screen brightness was far lower than I wanted it be by default.

To fix this I added a single line cronjob.  Crontab with cronjobs is a way to schedule when programs run automatically with one of the options being to run at boot up. It's a simple way to get something running each time you login. It's the system used by people who lets say want to check their network connection every hour.  Just setup a cronjob to run every hour and it will take care of it for you.   I used this previously to enable the Bluetooth keyboard and trackpad or the NexDock. (http://www.winkleink.com/2016/10/nexdock-thoughts.html)

So, I used crontab to set the brightness of the screen to 8 on startup.

In the terminal type:

crontab -e

If this is your first time it asks which editor you want to use.  I do [2] for nano.

Then the crontab file is opened where you put the jobs you want to run.

There are some comments in the file to help you get started, but if you want to do serious scheduled jobs then it's worth 

Go to the bottom of the file and type

@reboot brightness 8

Then the usual nano [CTRL]-[x] to save and close.  Answering [y] to save the file with the same name

Now when I start up the pi-topCEED the default brightness is '8' which suits me.

Finally, finally, the rricharz GitHub explains how to set the keyboard shortcuts for the pi-top laptop so the brightness keys work.  All good if I had a pi-top laptop, but I have a pi-topCEED where it's bring your own keyboard and the one I'm using doesn't have any fancy keys.

So, I looked up how to add keyboard shortcuts.  Again, it ends out to be not too hard.  Just added a couple of entries into a config file.

First thing I had to do is decide what key combination I wanted to use. I settled on:
[Shift]-[Windows Key]-[Up Arrow] for brighter

[Shift]-[Windows Key]-[Down Arrow] for darker

To do this you need to edit the lxde-pi-rc.xml file.

The file is a in a hidden folder in your home folder. If using the default user pi then the following command will open it 

nano /home/pi/.config/openbox/lxde-pi-rc.xml

As the file is in the home folder it doesn't need sudo to edit it

Then scroll down to the keyboard section and add the following to the end.

Easiest way is in nano find the </keyboard> text using the command [Ctrl]-[w] to do a Where is

Make sure you use spaces for the indent and get the <keybind> to line up with the other <keybind> entries

    <keybind key="S-W-Up">
      <action name="Execute">
        <command>brightness increase</command>
      </action>
    </keybind>
    <keybind key="S-W-Down">
      <action name="Execute">
        <command>brightness decrease</command>
      </action>
    </keybind>

To finish like above use [Ctr]-[x] to save and close.

To test select [shutdown] in the drop down menu and then [logout].

No need to reboot to enable the keyboard shortcuts.

Once you log back in the lxde-pi-rc.xml setting will be re-enabled and the 2 new key bindings will be active giving you the ability to change the brightness of your pi-top/pi-topCEED using [Shift]-[Windows Key]-[Up Arrow] and [Shift]-[Windows key]-[Down Arrow]

This has been a fun little project to improve the use of the pi-topCEED.
I like the work rricharz has done getting the pi-topHUB to turn off completely and to control the brightness as well as Laura Sach has done to make guizero so easy to use.

With the help of other peoples effort I now have the pi-topCEED completely shutdown as well as the Raspberry Pi and the ability to change the screen brightness using either a little gui app or with the keyboard.  Not a bad result for a couple of hours.

If you have any questions let me know in the comments.

Spider Chart maker using Python and Pygame

16th May 2017 - Updated to make the output an A4 landscape page.
Also, provided Inkscape created SVG file so you can prepare you can add your own School or Club name.  Make sure the final PNG resolution for __spider.png is 3508 x 2481 as the dot locations are hand coded for the spider to be in the location it is on this size of image.

Example of improved chart.

A few days ago a call went on out on Twitter for how to make lots of Spider Charts, also known as Radar charts in a programmatic way.  I decided to take up the challenge.

Twitter, help! Skill hexagon things...what are they called? How could I get a computer to make them based on data? https://t.co/WL4Bf7vvjy

— Sway Grantham (@SwayGrantham) June 19, 2016

The code and associated files are available to download from GitHub

Below is a sample completed chart

To do this I started with a blank version of the chart and added the person name top left and the red dots and lines for the individual scores.

The program is written using Python and Pygame and was developed on the Raspberry Pi.

Since it doesn't use any other external libraries I'd expect it to work on other systems with Pygame installed.

To achieve this 2 external CSV files and a large (3508 x 2481) blank chart image are used.

The image file is: __spider.png

spider_data_points.csv is a comma separated variable list of the co-ordinates on the 3508 x 2481 image for the individual points.  By using a separate lookup if this was to be adapted to a different chart then you can just use a new master image and a different set of co-ordinates.

Student_Scores.csv is the file with the individual student (in this case) names and scores for the different skills.  There is no limit to the number of students that can have charts created as the code just goes through the csv line by line and creates a chart for each one.

Rather than creating the csv files manually it is so much easier to use a spreadsheet for data entry and then [Save As] a .csv
To facilitate this I've include .xlsx versions of the files.
These can be open and saved on the Raspberry Pi using OpenOffice.

Meaning if you needed to make 100 of these charts it would be a simple matter of:
Place all the code in a single directory
Enter the data in the spreadsheet.
Save as a .csv
execute spiderchart.py
Watch as all the charts are created automatically with the student name as the filename

Don't worry if the image is mainly off screen it is still being done correctly.

In the code there is a 1 second sleep after each chart is created. If you are doing lots then it might be worth commenting out the sleep.  It's useful for seeing what's going on.

As a complete side note: I was one of the backers of the Indiegogo pi-topCEED an All-in-One form factor for a Raspberry Pi desktop and it was delivered and set up on Monday.  It came with a Raspberry Pi 3.  This was the set up I used to develop and run the code.  I was very impressed by the quality of the 14" screen on the CEED.  This is now set up as the permanent home computer that my kids can use for playing Minecraft and exploring the CEEDuniverse, a game that teaches you about computers, coding and electronics.