Bits

June 29, 2025
In case anyone from Italy stumbles upon some old oscilloscopes branded as TELAV¹:
They are all rebranded Hung Chang oscilloscopes, especially the “TELAV 09635” (a rebranded “Hung Chang OS-635”) and the “TELAY 09620” and “AWS MODEL 620C”² (both rebrands of the “Hung Chang OS-620”).
1. TECNICHE ELETTRONICHE AVANZATE S.a.S., sometimes misread as TELAY due to the horrible graphic design of their logo ↩︎
2. A.W. Sperry Instruments, Inc. ↩︎
Tags: #Electronics
June 13, 2025
It turns out that the PWM signal on PC fans doesn’t require much current. Max 5mA according to the Intel specifications.
2.1.4 PWM Control Input Signal from the Intel specification
Source
The trick is to place a driver inside the fan capable of obtaining the necessary voltage/current.
Schematics for the driver circuit inside the fan
Source
This exonerates the MoBo engineers from accounting for high current requirements when designing the PWM controller and avoids wasting energy driving up and down a potentially high current through the connectors and cables.
Tags: #ATX #Electronics
March 30, 2025
Fun little games/challenges about control:
https://janismac.github.io/ControlChallenges/
March 25, 2025
From “Control of Machines with Friction - Brian Armstrong”
Click for more
Friction is universally present in the motion of bodies in contact. The modern science of tribology seeks to explain the atomic details of friction; but the universality of friction may also be understood from a different perspective. Leonardo da Vinci, among his many investigations, studied the relationship between friction and the music of the heavens. He knew the music to be produced by the bumping and rubbing of the heavenly spheres and was concerned with the possibility of friction between these heavenly bodies:
“Had however this friction really existed, in the many centuries that these heavens have revolved they would have been consumed by their own immense speed of every day … we arrive therefore at the conclusion that the friction would have rubbed away the boundaries of each heaven, and in proportion as its movement is swifter towards the centre than toward the poles it would be more consumed in the centre than at the poles, and then there would not be friction any more, and the sound would cease, and the dancers would stop …” Leonardo da Vinci (1452-1519), The Notebooks, F 56 V
The music of the heavens being eternal, Leonardo understood that friction is absent from the state of grace. Thus confined to this mortal world, friction is a consequence of original sin.
February 23, 2025
Quanser Interactive Labs v1.0.0.5 for MATLAB 2019b:
https://quanserinc.box.com/shared/static/lhf0gilgy1zu5hedkokb9mi025gzcu19.zip
Source
Tags: #Quanser #Matlab

December 25, 2024

How to add your private keys to the native Windows SSH client:

powershell 1
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# By default the ssh-agent service is disabled. Configure it to start automatically.
# Make sure you're running as an Administrator.
Get-Service ssh-agent | Set-Service -StartupType Automatic

# Start the service
Start-Service ssh-agent

# This should return a status of Running
Get-Service ssh-agent

# Now load your key files into ssh-agent
ssh-add $env:USERPROFILE\.ssh\id_ecdsa

Source

Tags: #SSH #Windows

November 11, 2024
Enabling OverlayFS for Raspbian
shell
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sudo raspi-config nonint enable_overlayfs
reboot
To disable it:
shell
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sudo raspi-config nonint disable_overlayfs
reboot
Tags: #Raspbian
October 27, 2024
How to use LibreOffice to convert in PDF all the .doc files in a folder
bash
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mkdir pdfout soffice --headless --convert-to pdf --outdir ./pdfout *.doc
It also works with .docx, .ppt, .pptx etc
Tags: #LibreOffice
October 27, 2024
bash
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echo "Hello World"