An exercise at converting an arbitrary video clip into ASCII-art.

One of the throw-back activities in Computing, which has existed since the 1990s, was so-called ‘ASCII-Art’, in which regular characters represented an image.

When this form of Art is created by a Human, it can look quite nice. But, if a mere computer program is given a sequence of images to convert into characters in a batch-process, the results are usually inferior, because all the program will be able to do is, to translate each cell of the images to an ASCII character, the brightness of which is supposed to represent the original brightness of the cell of the image. The complex shape of the actual text characters is not taken into account – at least, by any programs I have access to – and will also interfere with the viewer’s ability to recognize the intended image, because those shapes will just represent some random ‘noise’ in the image, without which, merely to have been given grey-scale tiles would have probably made it easier for the viewer to recognize the image.

In spite of recognizing this, I have persevered, and converted an arbitrary video-clip of mine into ASCII-art, programmatically. The following is the link by which it can be viewed:

(Link within my Web-site.)

And Yes, the viewer would need to enable JavaScript from my site, in order to obtain an actual animation, because that is what advances the actual ‘iframe’.

 

(Updated 6/22/2021, 19h15… )

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A realistic way of driving LEDs.

One concept which has existed for some time is, that LEDs can produce a variable amount of light, and this will be the case, regardless of whether that amount of light needs to be constant, modulated slowly, or modulated at very high frequencies. But, LEDs have as a property which many other components do not have, that they tend to produce a fairly constant, forward voltage drop (like any diode), but that, as the voltage increases only slightly past a certain point, current increases rapidly. And, in the History of Electronics, this has often caused circuit designers to put a resistor in series with the LED, to regulate its current accurately.

One big drawback of doing this is, that power gets wasted, as current flows through the resistor, and gets transformed into heat. The amount of power that gets wasted in that way, most strongly depends on what fraction of the supply voltage appears across the resistor, instead of across the LED. Another drawback is the fact, that the current which flows through a resistor, which has simply been connected between a supply voltage and an unpredictable component – such as the LED – is itself not constant, And, when supply voltages are low – such as 5V – small changes in supply voltage are large, in comparison to the only slightly smaller voltage-drop across the resistor. And so, technology does offer as alternative, a chip, with active components to regulate the current more precisely, and often, while wasting less energy. In principle, such a chip can also be installed by the manufacturer of LEDs, into the same package as the LED.

According to the schematic below, I have demonstrated such a circuit…

 

IMult_LED_1

 

What is happening here is, that A presumed control current is fed in to a presumed input pin, and this circuit actually doubles that current, resulting in an amount of current which will be drawn from the cathode of the LED. Additionally, more than one LED could be connected in series, to the current-sink.

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Some dissonance over the question, of the propagation speed of signals along microstrips.

The following frame states an observation which I recently made, about some equations describing transmission lines (that can exist, etched onto PCBs). Most browsers will require that JavaScript from my site, as well as from ‘mathjax.org’ be enabled, to be able to display it correctly…

(Updated 6/11/2021, 23h50: )


 


 

Dirk

 

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Inserting coupled inductors into NG-Spice’s netlists graphically.

I have spent quite a few postings, describing how the Open-Source circuit simulation programs “NG-Spice”, belonging to the “gEDA” suite, can be used. And one of the facts about them which I’ve recognized, is that they essentially come as three programs: The (non-GUI) engine which simulates Netlists; ‘gschem’, a graphical program which allows schematics and custom symbols to be edited; a third (GUI-based) program, ‘GSpiceUI’, that can import the schematic and export the netlist of a simulation to be run, as well as run the simulations.

What the first two programs do, isn’t always well-matched. ‘gschem’ can create schematics, with no regard for the fact that the Spice engine can’t simulate all the components.

But, One capability which NG-Spice has at the level of Netlists is, to simulate “coupled inductors”, which are denoted by a ‘RefDes’ which begins with the letter ‘K’.

Why is this potentially useful? Because, if the user simply puts the standard, library transformer, what NG-Spice will simulate, is a perfect transformer, which behaves as well at 60Hz, as it does at 60MHz. The user would have no way to specify any of that transformer’s parameters, then. It’s often more useful to simulate components, with built-in parasitic flaws, such as, coupling constants that are 0.99 or 0.9 instead of 1.0…

It would be nice, just to be able to drop such a coupling into a ‘gschem’ schematic, and have ‘GSpiceUI’ create its simulation ‘the easy way, via the GUI’.

Well, that can be prepared. And, the way to prepare it is, using ‘gschem’ in order to define a custom symbol…

 

coupled-inductors-1

 

(Updated 6/09/2021, 16h35… )

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