RGB (Red, Green, Blue) is the model we use to represent colors in computers, cell phones, cameras and the web. RGB color is everywhere and understanding its workings and limitations is a must for an exploration of digital color theory.
This brief article explains how digital devices use Red, Green and Blue to represent color, how color in general is identified and how a set of RGB values relates to the color we end up seeing on the display. Some important basic concepts like Hue, Colorfulness, Luminance and White Point are explained in a concise manner, by example. Continue reading →
After buying an AmazonBasics HDMI cable I noticed a "HIGH SPEED with Ethernet" sticker in the connectors. I didn't know what it meant so I searched a bit to find out what these cables are capable of. I hope this article makes clear whether you need an HDMI with Ethernet cable or not, and how to make use of the Ethernet feature.
If all you want is the good ol' HDMI cable, it doesn't matter whether it has Ethernet or not. All HDMI cables work for the vast mayority of applications, which are normally just transferring HD video and audio. Any device needing an HDMI cable can use an HDMI with Ethernet cable just fine. Continue reading →
This article presents a step by step guide for building a 1 bit memory using just BJTs (bipolar junction transistors) and resistors. It's a nice and simple educational project as it shows how data can be stored in a circuit using basic parts only. I created several diagrams to make each step clear. The complete diagram is at the end of the article. The project is based on DIY RAM Memory: Register Style instructable, with a few minor changes. Following the steps and testing the circuit after each step is recommended, specially if not using the transistors and/or resistors suggested below.
Consider the basic SR latch consisting of two interconnected NOR gates:
The idea of the DIY RAM project is to first implement the NOR gates using BJTs and then add some simple logic to transform the SR latch into a D latch, which is basically a 1 bit RAM. Finally, switches will be added at the input and an LED at the output in order to be able to write/read the bit easily.
Getting Latex accents and other special characters to work can sure give one a headache. In this article you'll see how easy it is to get your accents working once you know exactly what you're doing.
As explained here, Latex uses the ASCII character set by default. ASCII has only 128 characters which are not enough for languages other than English. This means Latex does not recognize accents, tildes, the circumflex, diaeresis, cedilla and others by default. Continue reading →
As a Costa Rican blogger I felt it was time to write my first article about my beatiful country. This article tries to briefly describe Costa Rica as it is, from the inside, with all its beauty and problems. It is aimed at travelers that want to learn both the good and the bad before adventuring into this great country. It's a short read. You won't be bothered with specific info you'll probably forget right away.
Costa Rica is a Central American tropical country with a population of 5 million. It's the only Latin American country with absolutely no military forces. Because it was colonized by Spain, the native language is Spanish, spoken through all the country. Almost half the population is concentrated near the capital, San José, which is close to the center of the territory. The country is divided into seven provinces.
We have one of the oldest and more stable democracies in the world. Costa Rica is known for being a free, peaceful and happy country and as far is I can tell it is true (not Heaven though).
The climate is, of course, tropical, with a dry (December to April) and a rainy season (May to November). The mean temperature is 20 C in the capital and metropolitan area and 27 C at the coasts.
If you are here you've probably heard of HSL, HSB or HSV color models. They are nothing more than transformations of RGB values. Simple equations are used to convert from RGB to HSL and HSV color. HSB is exactly the same as HSV, but HSL is slightly different as explained below. Because they are both based on RGB, they are also meant to be used to represent color in digital devices. This article explains the basic definitions involved (no previous knowledge on color theory is assumed) and shares the equations to convert between them.
Why did they bother creating color models that represent the same colors RGB already could? Although RGB is perfect for machines, it is not very human-friendly. HSL and HSV color models were created as a more convenient way for us to specify colors in software.
H stands for Hue and S stands for Saturation in all cases. Hue is usually a number between 0 and 360 that represents the angle in the color wheel (a hue wheel, that is). The B in HSB stands for Brightness and the V in HSV for Value, which are exactly the same: the perception of the ammount of light or power of the source.
Both Saturation and Brightness/Value are given as a real number between 0 and 1 or as a percentage. Playing around with the HSB fields of a color picker is probably the easiest way to understand these intuitive concepts.
HSL is slightly different. Hue takes exactly the same numerical value as in HSB/HSV. However, S, which also stands for Saturation, is defined differently and requires conversion. L stands for Lightness, is not the same as Brightness/Value. Brightness is perceived as the "amount of light" which can be any color while Lightness is best understood as the amount of white. Saturation is different because in both models is scaled to fit the definition of brightness/lightness.
The Toshiba Satellite A215-SP5816 drivers are not available from Toshiba's website as this is an old laptop. I'm posting them here as separate downloads and also as a complete driver pack. The drivers may also work for other Toshiba A210/A215 laptops. All are tested and working on Satellite A215-SP5816 under Windows XP.
The C Puzzles by Gowri Kumar are fifty C language programs meant to be compiled, run and explained. It's a great resource for those who are learning C. You'll learn the most if you use this post to compare with your own answers.
I took the time to understand and answer the first 25 problems. I'm not a C programmer (just know the basics) but did my best to explain each program both from my knowledge and googling for answers. Don't believe these are the correct answers as they may in fact be wrong. Most of the C puzzles answers may be found on different forums and Q&A sites but were not gathered on a single place before. Hope it helps. Please leave feedback and let me know any errors you find using the comments at the end of the page.
In this article I explain a choice of parts for building a quad-core desktop PC using the AMD A8-6600K APU. If you are here just for the part list see Review.
AMD APUs offer great benefit at low cost by integrating CPU and GPU on a single chip. It's a great deal for those who want a budget PC for everyday tasks and even capable of some discrete gaming. The third (latest) generation AMD A8-6600K Processor is a 4.3GHz quad core processor that costs $105. It integrates a GPU marketed as Radeon HD8570D though it's not comparable to "real" HD8000 GPUs. The socket is FM2, for which there are plenty of motherboards, most at low cost.
The Sabrent 6-Channel 5.1 PCI sound card may give a lot of trouble when installing it on Windows 7 x64. I'll share the steps I took to make it work.
The official Sabrent 32 bit driver for Windows 7 may be found here. However, this driver is not compatible with Windows 64. There are two solutions. The one given by Sabrent's technical support is to install the Windows Vista 64 bit driver. Download it from adf.ly/K1t8E.
A lot of people reported errors using this driver. If this is your case, the second option is to use the Aureon 5.1 unofficial driver: