Technology

To Get or Not To Get a Raspberry Pi

I have been chewing over whether or not to buy a Raspberry Pi 3 B+ single-board computer. They are generally priced at $35, as that is what the non-profit that designed them charges as a recommended price. As the firmware is partially closed source, there really aren’t exact Chinese copies, unlike many of the popular development boards like the 8-bit Arduino Nano or the many flavors of ESP 32 boards.

If I got a Raspberry Pi board, I would get a protective case, and I would most likely use it more like a computer then a microprocessor. While I have an SD card, I would need a case and a power supply. So I am probably looking at $50, which is more money then I really want to spend on a non-essential “toy” especially with my budget as tight as it is. I have a extra microSD cards, and a wireless USB keyboard with built-in track-pad that I could the Raspberry Pi with, along with my nice HDMI computer monitor, which only rarely really gets turned on. Most of my existing 5 volt supplies don’t really go beyond an 1.0 amp, with the except of the 4-plug unit I keep by my bed for charging my phone, radio, and headphones.

The Raspberry Pi is a bit different the Arduino and ESP 32 boards that use micro-controllers that I’ve worked with in the past. They are for one thing a fair bit more expensive. They aren’t microcontrollers, so they aren’t great at doing a single task repeatedly — but can do many tasks at once, but are not as well timed. The Raspberry Pi is essentially a mini low-powered computer, indeed the default software with it will boot a light version of Linux including a graphical interface and web browser.

The Pi uses upwards of 10 watts of power or 2,500 mA 5 VDC, which is quite a bit of power, although like my laptop, I would unplug itΒ  when not in use. My laptop obviously uses more — 43 watts when charging — although it’s certainly a lot more efficient then computers even a generation ago.

For home projects, I would much rather use the much lower power $2 8-bit Arduino Nano (20 mA) or the slightly higher power (50 mA) but much more powerful $6 ESP 32, compared to the $35 Raspberry Pi that pulls upwards of 2,500 mA. Microcontrollers, with their simple, more straightforward design, are much better for my hobbyist electronic projects, because usually the tasks I want to do at home are things like controlling a display module or making lights switch on and off automatically — not something that requiresΒ  a full operating system to implement.

It’s true that many microcontroller-type projects can be implemented on the Raspberry Pi using a bash or python script, but it’s overly complicated and takes a while to boot up, and burns through a lot of electricity if constantly powered up — especially as I’m trying to minimize my energy consumption both for environmental reasons and because I need to maximize deficiency I’m hoping to eventually live in an off-grid house, with limited solar and batteries

I guess my question is in reality how much use would I get out of the Raspberry Pi? It might be nice to have a second computer, something small that I could plug into my monitor for displaying photos, light-web browsing when I’m out in the field for work, maybe even playing video. It’s Linux-based, so I could script things that I need to. It’s obviously too underpowered though to do GIS work for map making.

So while I kind of want to buy a Raspberry Pi to play with it but with my limited budget and unclear plans for using it, I am thinking of holding off. I think over-time, computers on a board will only become more powerful and cheaper. Spending $35 or even $50 might not seem like a big deal when I drive a truck that sucks $60 or $70 of gas down a time, but it’s still tough to fit in my budget.

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Westinghouse 1,500 kilowatt Rotary Converter – YouTube

Most trolley and subway systems used 600 VDC. Yet the power grid and most stand-alone power plants use turbo-alternators to generate AC power. One way to convert AC to DC is to physically bolt an alternating current motor to a DC generator. Obviously this is inefficient, and DC generators are brushed-motors, and the brushes would wear out and regularly have to be replaced.

By the 1930s, these rotary converters were replaced with mercury vapor arc rectifiers, which where large glass vats of mercury, that allowed current to only flow one way. In many ways they are much cooler looking as they glow -- almost something from a sci-fi movie. Being solid state without moving parts, mercury vapor arc rectifiers often saw service for many decades, well into the 2000s. See here: https://www.youtube.com/watch?v=QY6V2syGnZAI

Chemists discover how blue light speeds blindness

Chemists discover how blue light speeds blindness

This article has been making the rounds on the Internet.

How can blue light from screens be much worse then bright sources of blue light that we see much brighter in daylight or even mercury-vapor street lights, that lit up cities in the 1950s and 1960s, and still do in many small towns?

While I don't dispute exposure to blue light in the evening can keep people awake, I can't imagine blue light at night is bright enough to do any retina damage compared other natural sources of blue light.

Spies Are More Common, and Boring, Than You Think

Spies Are More Common, and Boring, Than You Think

"One former American counterintelligence officer estimated that there were about 100,000 foreign agents spying on the U.S., working for about 60 to 80 nations. To put that in perspective, there are about 50,000 coal miners in the U.S., or half the number of foreign spies."

"But I wonder if the actual number of foreign spies isn’t larger yet. John Negroponte, former director of national intelligence, admitted in 2006 that the U.S. was deploying about 100,000 spies around the world. Given that the U.S. is the world’s technology and military leader, and yet has a relatively small share of global population, is it so crazy to think the number of people spying on us is larger than that?"