Senior citizen-friendly video telephony system with a Raspberry Pi
Picking Up a Phone Call
The receiving side does not need to go through as much trouble because I assume that the children and grandchildren have a PC or smartphone. To receive the call from grandma and grandpa, all they have to do is open the link from the email into a web browser, and the grandparents appear on the screen.
Theory and Practice
During the first field test of the full setup, massive interference in the microphone signal occurred in Jitsi. In a direct test of the microphone and sound card (on the Raspberry Pi and a Windows PC), the errors could not be reproduced, so the hardware is obviously not responsible.
The explanation was too weak a power supply, which was overtaxed by supplying power to the Raspberry Pi, sound card, and webcam. A better power supply quickly provided a remedy; alternatively, the use of a USB hub with its own power supply is also an option.
It turns out that the third generation of the Raspberry Pi is overtaxed by high-definition video telephony. Transferring the picture and sound without interruption proved to be a difficult task. On the one hand, the latency caused a noticeable delay during the call. On the other, the echo and acoustic feedback effects disturbed the sound because I couldn't shield the webcam's microphone against the TV's speakers.
If you don't want to upgrade to a far more powerful Raspberry Pi 4, you can mitigate both issues by reducing the CPU load during the video call – which is why Jitsi is called with the parameters shown in the scripts. The picture and sound quality are not perfect, but good enough.
Sources of Error
In the initial phase with the video telephony system, it quite often happened that my grandparents accidentally switched their Sony TV to standby with the remote control while the Raspberry Pi was still running. After that, setting the HDMI input to inactive did not work as desired because the TV did not know what signal source it had been displaying before the Raspberry Pi. The Raspberry Pi's HDMI input remained the last activated input source, and my grandparents needed help because they did not know how to switch to the TV function on the TV. Disaster: the TV stayed black even after it was switched back on.
The attempt to switch the signal source actively to a TV channel by CEC before shutdown did not succeed. In the worst case, the TV still showed a black screen after switching on, but at least it switched back to a TV channel after starting and shutting down video telephony. Some CEC functions are supposed to control the TV's digital tuner remotely; however, in the setup used here, the call from the Raspberry Pi reported that the command was not recognized.
The Sony's remote control has a button for switching between analog and digital, which can also switch the signal input back to the TV. Fortunately, I could communicate this information by telephone. Happily, my grandparents only make this mistake once in a while and should improve their skills over time. To eliminate this source of error completely, the system would have to be given its own TV set. Smaller devices are available second-hand for just a few dollars.
« Previous 1 2 3 4 Next »
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Direct Download
Read full article as PDF:
Price $2.95
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Find SysAdmin Jobs
News
-
KDE Plasma 5.27 Beta is Ready for Testing
The latest beta iteration of the KDE Plasma desktop is now available and includes some important additions and fixes.
-
Netrunner OS 23 Is Now Available
The latest version of this Linux distribution is now based on Debian Bullseye and is ready for installation and finally hits the KDE 5.20 branch of the desktop.
-
New Linux Distribution Built for Gamers
With a Gnome desktop that offers different layouts and a custom kernel, PikaOS is a great option for gamers of all types.
-
System76 Beefs Up Popular Pangolin Laptop
The darling of open-source-powered laptops and desktops will soon drop a new AMD Ryzen 7-powered version of their popular Pangolin laptop.
-
Nobara Project Is a Modified Version of Fedora with User-Friendly Fixes
If you're looking for a version of Fedora that includes third-party and proprietary packages, look no further than the Nobara Project.
-
Gnome 44 Now Has a Release Date
Gnome 44 will be officially released on March 22, 2023.
-
Nitrux 2.6 Available with Kernel 6.1 and a Major Change
The developers of Nitrux have officially released version 2.6 of their Linux distribution with plenty of new features to excite users.
-
Vanilla OS Initial Release Is Now Available
A stock GNOME experience with on-demand immutability finally sees its first production release.
-
Critical Linux Vulnerability Found to Impact SMB Servers
A Linux vulnerability with a CVSS score of 10 has been found to affect SMB servers and can lead to remote code execution.
-
Linux Mint 21.1 Now Available with Plenty of Look and Feel Changes
Vera has arrived and although it is still using kernel 5.15, there are plenty of improvements sure to please everyone.