Connecting 7" touchscreen display to Raspberry Pi 4B

1.0 Introduction Raspberry Pi 4B has a Display Serial Interface (DSI) port for connecting a Raspberry Pi touchscreen display using a ribbon cable. In this post we will look at the process of connecting the Raspberry Pi 7″ touchscreen display with the Raspberry Pi 4B single board computer. 2.0 7″ touchscreen display The Raspberry Pi …

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Getting started with Raspberry Pi

1.0 Raspberry Pi Raspberry Pi is a popular single board computer developed by the Raspberry Pi Foundation in the U.K. Raspberry Pi 4 Model B (Pi4B) was released in June 2019. The main components of Pi4B are: The system-on-chip, (Soc). This is the Broadcom BCM2711 SoC, which uses the 64-bit ARM Cortex-A72 quad-core processor as …

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Gimp: How to stack the main window over the toolbox and layer windows

When Gimp is installed fresh, the toolbox and layers windows are stacked on top of the main window and it is not possible to get the main window on the top. This can be quite annoying since one works mostly on the main window and the other two are required only once in a while. …

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Everything is too small on desktop at 1080p

After installing Ubuntu Linux on a laptop with screen resolution 1920×1080 pixels or more, you may find that the icons and text appear to be small. You can alleviate the problem by taking the following steps. 1. Install gnome-tweak-tool $ sudo add-apt-repository universe $ sudo apt-get install gnome-tweak-tool 2. Run gnome-tweak-tool Click on “Show Applications” …

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Wacom tablet not connecting with Ubuntu Linux

1.0 Error Wacom tablet connected to a laptop Wacom One CTL-672/KO-CX tablet was not connecting with a laptop running Ubuntu Linux 18.04 LTS. It was working fine earlier, with the wacom driver obtained from the Linux Wacom Project. The Linux kernel on the laptop had been updated recently. The following error messages were observed. $ …

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Connecting Wacom One CTL-672/KO-CX tablet to Ubuntu Linux

Wacom One CTL-672/KO-CX is an 8.5 inch x 5.3 inch graphic tablet which can be connected to a computer via a USB port. The tablet comes with a pressure sensitive cordless pen. Once connected to a computer via a USB port, pen and tablet work like a mouse on a mouse pad, giving a very …

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nginx 502 Bad Gateway

1.0 502 Bad Gateway After the update of Linux on the web server, the website would not open in the browser. Instead the following error was displayed. 502 Bad Gateway nginx/1.14.0 2.0 Solution First we check the nginx server. $ systemctl status nginx ● nginx.service – A high performance web server and a reverse proxy …

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How to trim a string in C

The problem of removing leading and trailing whitespace characters in strings occurs in programming quite often. Here is a solution. #include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h> void trim (char *dest, char *src); int main (int argc, char **argv) { char inbuf [1024]; char outbuf [1024]; printf (“Type a string : “); while (fgets …

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Socket programming using the select system call

1.0 Client-Server Paradigm The Client-Server paradigm divides the software architecture of a system in two parts, the server and its clients. The server works in the background and maintains the system-wide database. Using the database, it provides the functions for system operation and responses to queries from the clients. The clients provide the user interface …

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