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Quorten Blog 1

First blog for all Quorten's blog-like writings

T-Flash = MicroSD

quorten

2016-01-03

Categories: raspberry-pi  
Tags: raspberry-pi  

Raspberry Pi continued. I’ve got my multi-card reader, and I’ve found out that the TF slot is the MicroSD card reading slot. Why is there different names? Well, it turns out that MicroSD was originally going to be named T-Flash, except that T-Mobile sent a cease-and-desist letter asserting that T-Mobile owns a trademark on T-(anything). At least that’s what Wikipedia says, even though that particular sentence is marked with [citation needed].

20160102/https://en.wikipedia.org/wiki/Secure_Digital

Antennas and capacitor discharge pattern

quorten

2016-01-02

Categories: raspberry-pi  
Tags: raspberry-pi  

Antennas? Software-defined radio?

Wow, how did I end up popping up all of this from Wikipedia? Oh, I just asked a question one day, and I got my answer on Wikipedia. Yeah, in the past, this would have really went something more like I asked my question, and I wondered about it, but I never really got an answer. Yeah, technology can really change our lives. Change them for the better? I don’t know about that.

20160101/https://en.wikipedia.org/wiki/Software_defined_antenna
20160101/https://en.wikipedia.org/wiki/Radio_frequency
20160101/https://en.wikipedia.org/wiki/Cognitive_radio
20160101/https://en.wikipedia.org/wiki/RF_front_end
20160101/https://en.wikipedia.org/wiki/Antenna_%28radio%29
20160101/https://en.wikipedia.org/wiki/Antenna_%28radio%29
20160101/https://en.wikipedia.org/wiki/Digital_television
20160101/https://en.wikipedia.org/wiki/ATSC
20160101/https://en.wikipedia.org/wiki/Single_Frequency_Network
20160101/https://en.wikipedia.org/wiki/Very_high_frequency
20160101/https://en.wikipedia.org/wiki/Ultra_high_frequency
20160101/https://en.wikipedia.org/wiki/Rubber_ducky_antenna

To note. You ask, why do you need a longer antenna for lower frequency transmissions? Well, that is because of the photoelectric effect. Lower-frequency electromagnetic radiation has less energy associated with a wave of the same amplitude, so naturally, you are going to want to amplify it via a resonant antenna in order to get a sufficient amount of energy into your low-noise amplification circuit.

Read on →

Raspberry Pi Zero still sold out, powered USB hubs

quorten

2016-01-01

Categories: raspberry-pi  
Tags: raspberry-pi  

Well, there you go. Raspberry Pi all sold out, still unknown when the next batch will be available. Oh, no, for you, both the first and second batches are all sold out, and the third batch is still in waiting.

20151231/http://www.christianpost.com/news/raspberry-pis-5-zero-computer-sells-out-in-24-hours-151318/
20151231/http://www.element14.com/community/docs/DOC-79280/l/five-things-you-need-to-know-about-the-raspberry-pi-zero

How do you get a powered Raspberry Pi USB hub setup properly? Here’s how:

20151231/http://elinux.org/RPi_Powered_USB_Hubs

Unfortunately, the hub I purchased is not listed in the article above.

Wait, though maybe the above article is outdated. Note that backfeeding power is no longer an issue with modern Raspberry Pis.

20151231/https://www.raspberrypi.org/forums/viewtopic.php?f=46&t=29696
20151231/https://www.raspberrypi.org/forums/viewtopic.php?f=46&t=58452

Read on →

Raspberry Pi boot caveats

quorten

2015-12-27

Categories: raspberry-pi  
Tags: raspberry-pi  

DuckDuckGo raspberry pi boot from usb stick

20151226/http://jonathanmh.com/boot-raspberry-pi-from-a-usb-stick/
20151226/http://raspberrypi.stackexchange.com/questions/1187/boot-from-external-usb-stick-drive
20151226/https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=12015

ARG!!!! Can you boot a Raspberry Pi a USB floppy disk drive? How about a USB memory stick? How about a USB optical disk drive? How about a USB serial port? How about a USB Ethernet interface? No, no, no, no, and no.

Why can’t a Raspberry Pi boot from anything useful? Why does today’s technology have to be so brittle in its compatibility matrix?

Here’s why: The Raspberry Pi’s booting process is revolves around completely incompatible, non-standard, proprietary software. In fact, the Raspberry Pi is labeled as a single-board computer that has a fatal flaw by the Free Software Foundation. According to Debian, the Raspberry Pi boots off of its GPU, and its GPU needs to load its firmware from the SD card. Without the firmware, the proprietary binary blob, the Raspberry Pi cannot boot.

20160104/https://www.fsf.org/resources/hw/single-board-computers
20160104/https://wiki.debian.org/RaspberryPi
20160104/https://en.wikipedia.org/wiki/Raspberry_Pi#Driver_APIs

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More Raspberry Pi power and connector information

quorten

2015-12-27

Categories: raspberry-pi  
Tags: raspberry-pi  

Raspberry Pi, again. Note, the defect in the Raspberry Pi 2 power supply is particularly interesting. Because the power supply chip has no packaging, flashes of light can cause malfunctioning.

20151231/https://en.wikipedia.org/wiki/Raspberry_Pi
20151226/https://en.wikipedia.org/wiki/USB/
20151228/https://en.wikipedia.org/wiki/USB_Type-C

This page is particularly useful for determining the feasibility of taking some digital data interface and transferring it across USB.

20151228/https://en.wikipedia.org/wiki/List_of_device_bit_rates#Peripheral

20151228/https://en.wikipedia.org/wiki/Future-proof
20151228/https://en.wikipedia.org/wiki/Year_10000_problem

The Long Now Foundation? Always use 5-digit years? Really, it it were up to me, I would not be padding out my years to any number of digits if they were shorter or longer than the typical expected length.

20151228/https://en.wikipedia.org/wiki/Long_Now_Foundation

Read on →

Raspberry Pi power, boot, DMA, USB, Ethernet, phone connectors discussion

quorten

2015-12-22

Categories: raspberry-pi  
Tags: raspberry-pi  

Raspberry Pi and USB!

Note: Although USB supports video devices, the USB 2.0 bandwidth is not fast enough for a USB SVGA video capture device to make sense. Not unless the video stream is compressed.

You were wondering. Why do you have to supply power to an Ethernet switch? Why can’t it just get it from all of the connected computers? The reason why this is is due to the standardization of Ethernet. Ethernet standardizes electrical isolation; thus, the switch needs to have its own power source. USB, on the other hand, standardizes a common ground.

20151221/https://en.wikipedia.org/wiki/USB

Raspberry Pi power packs?

20151221/http://www.raspberrypi-spy.co.uk/2013/06/12000mah-li-on-battery-power-bank-test/http://www.raspberrypi-spy.co.uk/wp-content/uploads/2013/06/pi_power_bank_test_03.jpg
20151221/https://www.raspberrypi.org/forums/viewtopic.php?t=19341
20151221/http://makezine.com/projects/portable-pi-power-raspbery-pi-to-go/
20151221/https://www.raspberrypi.org/forums/viewtopic.php?f=46&t=6457

Read on →

How VidFIRE changes the frame rate

quorten

2015-09-13

Categories: media-prog  
Tags: media-prog  

So how does VidFIRE change the frame rate? It doesn’t just do a frame interpolation, does it? Nope, it uses motion estimation to move various pixel regions in their direction of motion. But even better, would be to use object fidelity reconstruction with the help of a 3D object recognition system. However, that is beyond our current technology, I guess.

20150912/https://en.wikipedia.org/wiki/VidFIRE
20150912/https://en.wikipedia.org/wiki/Motion_estimation
20150912/https://en.wikipedia.org/wiki/Colour_recovery
20150912/https://en.wikipedia.org/wiki/Wiping
20150912/https://en.wikipedia.org/wiki/Reverse_Standards_Conversion

Wiping makes sense from a practical perspective, when the cost of the media is very expensive, though there tends to be a lot of modern complaints about the practice.

Wow, very important find! Not only is it the method for identifying entertainment video works and such, it also takes an interesting approach to implementation.

20150912/https://en.wikipedia.org/wiki/International_Standard_Audiovisual_Number

Why photogrammetry takes so many resources, and fallacy of photographic memory

quorten

2015-09-12

Categories: 3d-scanning   3d-scanner   pentax-k-1-camera  
Tags: 3d-scanning   3d-scanner   pentax-k-1-camera  

So, revisiting the question. Why does modern photogrammetry take so many computational resources?

The reason why is because our present-day computer systems are designed for mathematical and visual perfection, whereas our brain is literally nothing but a bunch of cheap hacks on vision processing. And that’s why present-day computer vision solutions are so computationally intensive. It’s only what’s technically required to get that kind of degree of perfection. Human vision systems, by contrast, get by with far less perfection. “Perfect” images in our mind are progressively constructed by repeated exposure to certain objects and careful visual scanning of the object in question. Over time, our brain builds a more detailed image of the object in question. Well, some people can perform this process faster than others. Often times, in common language, we say these people have “photographic memories,” but in truth, they don’t, strictly speaking, because no human alive can actually see the individual “pixels” from their retina. The human brain only “sees” the post-processed information that their retina passes upward, which is a description of lines and patterns, not pixels. That is, not unless the pixels are large enough can the conscious brain actually see and measure in pixels passed upward from the retina.

The fallacy of photographic memory, that’s simply just not the way the human vision system operates.

Read on →

Differences between humans and computers

quorten

2015-09-12

Categories: misc  
Tags: misc  

Differences between humans and computers. In humans, only the highest levels of the brain are directly and quickly reprogrammable. In computers, every level of the machine is directly and quickly reprogrammable. Is there an advantage to the limitations of the human brain? Yes. Try holding your breath indefinitely, by only controlling your breathing from your brain but keeping your mouth and nose unobstructed, for example. Eventually, you’ll go unconscious, but when you do, you’ll start breathing again. Ah ha! Your lower levels of your brain knew that you were foolish, O pie-in-the-sky conscious intelligent being.

On the other hand, take this example. You’re sticking your hands inside of a tight computer case that was recently turned on. You happen to touch one of the heads of a high voltage capacitor and you get shocked. Your nervous system causes you to jerk indiscriminately and your hand rams up against a sharp metal edge inside the computer case and you get severely cut. Was that an intelligent thing to do? Of course not, but the low levels of your body could not have known any better.

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Discussion on technical capabilities of human eye versus digital camera/display systems

quorten

2015-09-12

Categories: media-prog   pentax-k-1-camera  
Tags: media-prog   pentax-k-1-camera  

Why can cameras take longer exposures than the human eye? Of course, that’s easy. Because a camera passes every single pixel of data to the general purpose computer chip it has onboard, then it can use whatever programmed algorithm one likes to process that image. Whereas, the human vision system has a mandatory fixed-purpose structure sitting between the eyes and the conscious mind that only features a limited range of processing functions. This is why you can’t tell your brain to do a long exposure on an image, or even better, to digitally refocus an image to compensate for your myopia or hyperopia. Nope, your brain can’t do that. The structures in your brain are grown and wired in as-is, without allowing for reprogrammability. You need a computer if you want to do that.

Well, these are important for my inventory system too. On describing human vision. Not fully developed until after 6 months of age from birth.

20150911/http://vischeck.com/
20191123/https://web.archive.org/web/20150911/http://tinyeyes.com/

Read on →