How to Make Computer Screen Go Blank as Prank or Penalty

• The article explains how to use SoX, a command-line tool that can manipulate audio data, to make your computer screen go blank for a certain period of time as a prank or a penalty.
• The article also shows how to automate this process using cron, a scheduling daemon that runs tasks at specified intervals, and how to customize the parameters of the silence effect and the virtual terminal to switch to.

Have you ever wanted to prank your friends or family by making their computer screen go blank for a few seconds? Or maybe you want to discipline your kids by turning off their screen when they are too loud or playing games for too long. In this article, we will show you how to use a simple command-line tool called SoX to make your computer screen go blank for a certain period of time as a prank or a penalty. You will also learn how to automate this process using cron, a scheduling daemon that runs tasks at specified intervals.

What is SoX?

SoX, which stands for Sound eXchange, is a cross-platform command-line utility that can manipulate various forms of audio data. It can play, record, convert, and apply effects to sound files and streams. It supports many audio formats, such as WAV, MP3, OGG, FLAC, and more. You can install SoX on Linux, Windows, and Mac OS X using the instructions on the official website.

How to Use SoX to Make Your Screen Go Blank

One of the effects that SoX can apply to sound data is silence. This effect can trim or pad sound data with silence, or detect periods of silence in the input. We can use this effect to make our screen go blank by sending a silent audio stream to the default sound device and switching the virtual terminal to a blank one.

To do this, we need two commands: sox and chvt. The sox command will generate a silent audio stream and send it to the default sound device (usually -d). The chvt command will change the virtual terminal to a different one. A virtual terminal is a console that you can access by pressing Ctrl+Alt+F1 to F6 on most Linux systems. By default, the graphical user interface runs on the seventh virtual terminal (F7), so we can switch to another one (such as F3) to make the screen go blank.

The syntax of the sox command for this purpose is:

sox -n -d silence [duration] [threshold] [padding]

The -n option means that the input is null (no sound data). The -d option means that the output is the default sound device. The silence effect takes three parameters: duration, threshold, and padding. The duration is how long the silence lasts in seconds. The threshold is how loud the sound has to be to end the silence (in percentage of maximum amplitude). The padding is how much extra silence to add at the end (in seconds).

The syntax of the chvt command for this purpose is:

chvt [number]

The number is the virtual terminal to switch to. It can be any number from 1 to 6, depending on how many virtual terminals are available on your system.

To combine these two commands, we can use the && operator, which means “run the second command if the first one succeeds”. For example, if we want to make our screen go blank for 15 seconds when the sound level reaches 10%, we can use this command:

sox -n -d silence 15 10% 0 && chvt 3

This command will generate a silent audio stream and send it to the default sound device. It will wait until the sound level reaches 10% of the maximum amplitude, then it will switch to the third virtual terminal, making the screen go blank. After 15 seconds, it will switch back to the seventh virtual terminal, restoring the graphical user interface.

How to Automate This Process Using Cron

If you want to make your screen go blank at regular intervals or at specific times, you can use cron, a scheduling daemon that runs tasks according to a predefined schedule. Cron uses crontab files to store the schedule and commands of each task. You can edit your own crontab file using the crontab -e command.

Each line in a crontab file has six fields: minute, hour, day of month, month, day of week, and command. The first five fields specify when the task should run, using numbers or special characters such as asterisk (*), comma (,), hyphen (-), and slash (/). The last field specifies what command should run.

For example, if you want to make your screen go blank for 15 seconds every hour at 17 minutes past the hour, you can add this line to your crontab file:

17 * * * * sox -n -d silence 15 10% 0 && chvt 3

This line means that at minute 17 of every hour of every day of every month of every day of the week, run the command sox -n -d silence 15 10% 0 && chvt 3.

You can use different values or special characters to specify different schedules. For example, if you want to make your screen go blank for 15 seconds every weekday at 9 am, you can use this line:

0 9 * * 1-5 sox -n -d silence 15 10% 0 && chvt 3

This line means that at minute 0 of hour 9 of every day of every month of days 1 to 5 of the week (Monday to Friday), run the command sox -n -d silence 15 10% 0 && chvt 3.

Frequently Asked Questions (FAQs)

Question: How can I stop the screen from going blank?

Answer: If you want to stop the screen from going blank, you can either make some noise above the threshold level, or press Ctrl+Alt+F7 to switch back to the graphical user interface. You can also edit your crontab file and remove or comment out the line that runs the command.

Question: How can I change the duration, threshold, or padding of the silence effect?

Answer: You can change the duration, threshold, or padding of the silence effect by modifying the parameters in the sox command. For example, if you want to make your screen go blank for 30 seconds when the sound level reaches 20%, and add 5 seconds of extra silence at the end, you can use this command:

sox -n -d silence 30 20% 5 && chvt 3

Question: How can I change the virtual terminal to switch to?

Answer: You can change the virtual terminal to switch to by modifying the number in the chvt command. For example, if you want to switch to the fourth virtual terminal instead of the third one, you can use this command:

sox -n -d silence 15 10% 0 && chvt 4

Summary

In this article, we learned how to use a simple command-line tool called SoX to make your computer screen go blank for a certain period of time as a prank or a penalty. We also learned how to automate this process using cron, a scheduling daemon that runs tasks at specified intervals. We hope you found this article helpful and fun, and that you will use this technique responsibly and ethically.

Disclaimer: This article is for educational and entertainment purposes only. We are not responsible for any damages or consequences that may result from using this technique. Please use it at your own risk and with respect for others.