Here at Provide Your Own, we are a big fan of LED lighting. Recent research has raised the alarm that LED lighting can cause retina damage. Is there any truth to this assertion? Can LEDs really be bad for your eyes, even causing blindness?
Fortunately for LED lovers, the answer is a resounding NO. When the facts are examined, if LEDs are bad for your eyes, then sunlight is at least ten times worse. Let’s first look at the basis for the assertion.
The Research Study
According to a sole news account:
The study found that LED radiation caused significant damage to human retinal pigment epithelial cells in vitro.
We irradiated naked retinal cells with intense light from LEDs in a petri dish and they didn’t do so well.
Keep in mind that damage would be done with any high intensity light. Have you stared into the sun lately? How about staring into lasers or high intensity LED flashlights? Think you might have some retina damage?
This research has not been peer reviewed, but is simply an account given by Dr Celia Sánchez Ramos. This fact does not invalid the research, but shows that we have absolutely no … Read the rest
Also posted in Health
Tagged led lighting
Ethernet (your computer network) only uses 2 pairs of wires. Cat5 cable provides 4 pairs, leaving 2 pairs leftover. You can use those two extra pairs to transmit power (in small amounts) to power remote equipment such as another router, switch or a bridge.
This additional capability is not provided by default. This article provides clear instruction on setting up your own Power Over Ethernet (PoE) network, including making custom adapters for injecting & extracting the power.… Read the rest
Posted in Tech
Tagged home networking
Conspiracies abound – there is no doubt about it. The media propaganda delights in lampooning anyone who believes that men would conspire together to further their interest (at least men in government; everyone else is fair game). While I am very skeptical of anything coming from either the mainstream media, the pharma industry or government agencies, I don’t throw everything out either. Two examples come to mind – free energy inventions (including 100+ mpg carburetors) and the Apollo moon landing.
In the case of free energy inventions, when they clearly violate the known laws of physics, they must be viewed very skeptically. It doesn’t matter who believes in them, what fantastic story is told about how the auto manufacturers strong-armed them out of business (or the oil companies), or how realistic it appears, it is very, very, very likely to be a hoax. Human gullibility knows no bounds, nor does human ingenuity to fool and exploit it.
Houdini spent years debunking séances. James Randi does the same with charlatans today. By all means keep an open mind, but when something sounds to good to be true, it probably is.
In the case of the moon landing, just because the government … Read the rest
Also posted in General
This fascinating video shows how lumber was harvested from giant redwood trees before the chainsaw.
Nowadays, some people get smug about how advanced we are. We might have some high-tech gadgets, but are we better for them, or worse? Looking at these fellows scaling a tree almost as fast as one can walk, and then to chop it down with an ax while suspended from its trunk is absolutely amazing.
Modern technology has not made us any better. In most cases, it simply removes the requirement of skill. Anyone can fell a tree with a chainsaw, but how many can fell in with a foot or two of precision as these guys could?
If we are to be more self-sufficient and less reliant on corporations and experts, we must learn new skills. Avoiding technology is not an advantage as some may think. What is important is not avoiding technology, but rather avoiding learning useful skills and relying on technology as a crutch.
We must be the master of technology, not its slave. Thoughts anyone?… Read the rest
Also posted in Skills
Have you ever wondered how digital cameras detect faces? If you thought that computer vision was rocket science and too difficult, that notion is no longer true.
There is this wonderful open source library called OpenCV that runs on Windows, Linux, Mac, iOS, Android and now RaspberryPi. Sophisticated visual algorithms are no longer limited to only high performance desktop computers. Using either your smartphone or a RaspberryPi, you can embed image detection in everyday life.
To get started, download the software needed for your device. Here are some nice tutorials to get you up to speed on using it.
Anyone using OpenCV? What are you doing with it?… Read the rest
Posted in Tech
I have been wanting a 10″ Android tablet, but they have always been too expensive. Sure, there have always been cheap Chinese knockoffs, but they have always been pretty junky affairs – until now.
My family recently bought me a . While this manufacturer does cut some corners, amazingly it didn’t cut the ones that count. It sports stereo speakers that sound better than the original Kindle Fire and has more memory as well. It even has a front facing camera and an HDMI output jack. Speed is decent and WiFi works just fine. It lacks the sensors of high end tablets and cell phones, but does have a microphone and accelerometer. It is perfect for viewing movies, PDF files, web browsing and Skype – typical tablet stuff. It also has USB input so you can easily attach a keyboard as well. You can also charge it via USB as well as using the supplied fast charger.
As for the downsides, there are remarkably few. Its ARM-based processor is only single core, and battery life is a tad less than the Kindle Fire, but decent. The biggest issue with this tablet is the lack of the Google Play store. Polaroid … Read the rest
Posted in Tech
When collecting any data on the Arduino, it won’t be very long before you need to calculate some statistics on that data. While statistics can be a pretty intense mathematical field, some very basic statistics such as calculating the mean and standard deviation can be invaluable for many applications.
Fortunately, it is not only easy to make these calculations, but its usefulness can extend beyond just statistics. Many times data from a sensor may not be stable. Touch sensing is a good example. Each individual value (data point) can vary quite a bit, making it difficult to make an accurate determination. By averaging these values, a better decision can be made.
In a similar vein, by calculating the standard deviation, you can assess the quality of the values obtained. A large deviation from the mean can indicate problems with your sensor.
Because statistics often require some extensive data collection, normal methods can be too memory intensive for small microcontrollers like the Arduino or ATtiny based designs. Normally each value is stored and, when all the data is collected, various calculations such as the mean and standard deviation are calculated on the data set. Storing this much data can … Read the rest
If you have any interest in either electronic circuits or micro-controllers, you have probably heard of the Arduino. Unless you have actually worked with the Arduino, you may only have a vague idea of what all the excitement is all about. If you are one of those who have wondered what the Arduino is, would like to know more about it, this article will answer most of your questions and give you a good grasp of the concepts.
Since this article is geared toward those with no or little prior knowledge of the Arduino platform, you may be inclined to skip it if you are more experienced. There is however, some useful information for the more experienced. You may often find yourself at a loss for words when describing the Arduino or your Arduino based projects to your family and friends. In that case, you might find this tutorial provides a good framework for improving your communication.
What is an Arduino?
The Arduino is a microcontroller based platform. It is not a microcontroller, but is an entire development/engineering environment and eco-system based on a family of microcontrollers from the Atmel corporation.
There are many microcontrollers from various corporations available, and … Read the rest
Unfortunately, there are no real standard sizes in the industry. Plugs & compatible jacks can vary by barrel diameter, pin diameter and barrel length. Even the polarity is non-standard. Some appliances actually use the center pin for negative/ground and the outer barrel for positive. You can determine which one is used by the pictorial representation found on the side of a gadget. It will show the pin and outer barrel and the polarity of each.
Even though there are two diameters that determine the size of the jack/plug, usually only the pin diameter is specified. For example, the popular 2.1mm jack has a barrel diameter of 5.5mm. The barrel diameter is assumed in most cases.
Despite the total lack of standards for household stuff, for the hobbyist, some popular sizes have emerged.
For low power connections, the pin diameter is 2.1mm and the barrel diameter is 5.5mm.
For higher current connections, having currents greater than 2.0 amps, the pin diameter is usually 2.5mm with a barrel diameter of 5.5mm.
Barrel length on the plugs seems to have settled at about 9.5 to 12mm long. The length match is not as critical as long as the plug is sufficiently long to … Read the rest
Posted in Tech
Section: Product Info
I recently tried to login into my Google account that hosts my YouTube channel. I had set the channel up a few years ago, and only used it once, so I had forgotten the e-mail address associated with it. Google however, lets you login using your channel name so that is what I tried to do. The problem was that since I had set up the channel, I also added a gmail address with the same username.
To my surprise, whenever I tried to login into my YouTube channel, it logged me into the gmail account, and that account had no YouTube channel. After some forum posts, a lot of research and trying a lot of things, I finally recovered my YouTube channel. For those in the same boat, there is a way to recover your YouTube channel, but the standard advice is a bit sketchy, and doesn’t really help without an understanding of what is going on. Here is how Google handles accounts:
Google Account Rules
The way Google sets up accounts, you provide a username and an e-mail address. The wrinkle is the fact that gmail accounts are also Google accounts. What is not obvious, is that they … Read the rest
Posted in Tech
Tagged security, youtube