As a result, I have often wanted/needed a way to verify that the server which is hosting my websites is up and running properly. While many fine graphical tools exist such as Munin for this purpose, I wanted a simple set of utilities that could return just the parameters I needed and how I needed them.
There are two different ways in which I want to get my metrics. The first is a command-line utility that I can run from my local computer to test the parameter needed. The second is a set of python functions that deliver the same metrics that I can then use to create a custom webpage.
This webpage (a future project) would run on a local server such as a , which could then display all my metrics on a tablet display in a convenient location. A quick glance could then show that everything was running smoothly or that problems … Read the rest
]]>Having a place for everything is key to a productive workbench.We want to make stuff, not look for stuff! :-)While we could make the cabinet out of wood, as long as your the parts are not too heavy, foam core is strong enough, inexpensive, and quicker to make than a wooden cabinet. Plus, no one has ever gotten splinters from foam core! đ
Source: Instructables.com
What a great idea for storing small parts like electronics, screws, buttons, etc. I like the idea of using foam core and hot glue. There are a lot of storage needs that can be met with foam core or cardboard instead of wood. Also, hot glue works great for these materials as well as wood. I made a silverware drawer divider from Luan plywood and hot glue years ago, that is still going strong.
Please add your own ideas in the comments.
… Read the rest ]]>
I wrote previously about why you should switch to Linux for all your computing needs. I would like to amplify on that assertion. There has never been a better time to abandon Windows and switch to Linux. First I’ll address the disaster that Microsoft Windows has become, and then explore the Linux alternative.
Just like the Titanic, even though there is widespread denial, Windows is sinking into the abyss just as surely. Despite the grave metaphor, I am not saying Windows will completely go away (who knows for sure), but it will continue to shrink into irrelevance. Linux rules both the server/cloud world and dominates the mobile market as well via Android. As applications continue to move to the cloud and mobile, the raison d’ĂȘtre for Windows as the only platform that can run the applications a user needs is slipping away.
But irrelevance is not the only thing ailing Windows. No siree. The operating system is strangling itself. Years of legacy code combined with a closed development system has left Windows years, even decades behind its competitors, namely Linux. Even the mighty resources that Microsoft have at its disposal cannot hope to compete with the … Read the rest
]]>With the loss of updates for Windows XP and Microsoft’s floundering on Windows 8/10, many have started to consider alternatives. The MacOS is of course an option, but I believe Linux to be an even better one. Not only is Linux a good alternative to Windows, but for makers, hackers, tinkerers and homeschoolers especially, Linux is really the only operating system (OS) worth considering.
Without a doubt, Linux is the ultimate low-cost operating system. It is absolutely free. How many times have you had a computer where the OS needs to be reinstalled? With Windows systems so vulnerable to malware infections, it is a regular occurrence. When you do need to reinstall, do you still have the original disks? Can they still be read?
What about upgrades? If you get a new computer (without an OS), and you want to install your latest version, do you have the full version, or just an upgrade version? If it is just an upgrade version, do you have the original version disks? If not, Microsoft’s DRM will not allow the installation.
Have you ever thought about building your own computer, but are stymied by the prospect of having to shell out … Read the rest
]]>The Arduino platform is great for prototyping. Its easy-to-use shield architecture, readily identifiable pin numbering scheme, and beginner friendly IDE and software library has created a large and loyal following. In the life of many projects, however, there comes a time when the project is to be permanently deployed. When that time comes, leaving a precious Arduino in the field is often not the best option. Instead, a specialized board with either an ATmega chip or even an ATtiny chip is the best choice.
When cost or space is a factor an ATtiny chip is an attractive alternative to the ATmega for simpler projects. Thanks to the Arduino-Tiny project, an ATtiny can be used as a drop-in replacement for most Arduino projects. This initiative provides ATtiny chip configurations as upload board choices in the standard Arduino IDE. By following the instructions described in my previous article – Program an ATtiny Using an Arduino – your Arduino sketch can be uploaded as easily to an ATtiny board as it can be to an Arduino one.
More recently, the ATtiny has gained semi-official support given the variants posted by David Mellis on Github. Please note that this new firmware specification … Read the rest
]]>How many microwaves have you thrown out because they get flaky after a few months? The thrift stores are full of these rejects. How many times have you wondered who designed the user interface for these things? What planet were they from? Wouldn’t it be nice to have a microwave that isn’t flaky and has a sensible interface?
Nathan did exactly that. He took a broken microwave and put in his own smarts via a Raspberry PI. It has a beautiful control panel, accepts voice commands and provides voice synthesized feedback. It even scans a product bar code to fetch cooking instructions. It is so smart, that you don’t have to babysit the thing to stop it to stir. With the bar code powered instructions, it will stop at the right time, tell you to stir, and start up again to finish the cooking. He even did a tablet interface.
The key to a project like this is a microwave with an intact magnetron, which is the tube which does the cooking. As already mentioned, most of the time these tubes are fine. It is the sorry electronics that flake out. Take inspiration from this guy. You don’t have … Read the rest
]]>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.
According to a sole news account:
The study found that LED radiation caused significant damage to human retinal pigment epithelial cells in vitro.
Translated,
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 SĂĄnchez Ramos. This fact does not invalid the research, but shows that we have absolutely no … Read the rest
]]>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 ]]>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
]]>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 ]]>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 ]]>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
]]>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.
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
]]>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
]]>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:
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
]]>When you finish the design and prototyping of your project and you want to make a PCB, you need to use some kind of PCB layout software. While there are a plethora of commercial products, most of them expensive – very expensive, there are relatively few that are low cost or free for the open source designer. This guide will look at the options available and make recommendations based on the author’s knowledge and preferences.
NOTE: There may be some other applications than the ones I have mentioned. Since I use Linux on my PC, I have only looked at the packages than run under Linux. I believe the ones listed run under all three mainstream operating systems, but I am only certain about Linux versions.
Some commercial PCB fabricators offer their own free online software. While some of these products may be quite capable, they suffer from one huge drawback – you are locked into their services. If you want to have your PCB made elsewhere, you are out of luck. For that reason I don’t give these programs a second look.
The Eagle CAD package offers both schematic and PCB layout programs. It … Read the rest
]]>Many circuits can benefit from protection against accidental reverse polarity.While most can be protected by polarized connectors to the power source, many hobbyist circuits and kits can be powered by jumper wires, thus eliminating this simple type of polarity protection. In these cases, a reverse polarity circuit would be a very useful addition to your circuit.
In this guide, we will explore three simple methods for adding this protection to your projects. This overview will only cover protection circuits on the high (positive) side of the circuit. Each of the protection methods can also be applied to the low (ground) side. The low side versions of these circuits offer the benefit of using NPN & N-channel devices instead of their PNP or P-channel equivalents, the former which are often cheaper, more readily available and sometimes higher performance. However, low side circuits change the voltage level of the ground path which could cause issues for some circuits.
If you wish to study low side approaches, App Note AN636 from Maxim is a good one to consult. I think for most circuits, the high side versions work very well and will prevent any possible problems with a low side approach. Therefore, we … Read the rest
]]>A little known feature of Arduinos and many other AVR chips is the ability to measure the internal 1.1 volt reference. This feature can be exploited to improve the accuracy of the Arduino function – analogRead()
when using the default analog reference. It can also be used to measure the Vcc supplied to the AVR chip, which provides a means of monitoring battery voltage without using a precious analog pin to do so.
I first learned of this technique from these articles – Making accurate ADC readings on the Arduino, and Secret Voltmeter. In this article, I have incorporated some additional improvements.
There are at least two reasons to measure the voltage supplied to our Arduino (Vcc). One is if our project is battery powered, we may want to monitor that voltage to measure battery levels. Also, when battery powered, Vcc is not going to be 5.0 volts, so if we wish to make analog measurements we need to either use the internal voltage reference of 1.1 volts, or an external voltage reference. Why?
A common assumption when using analogRead()
is that the analog reference voltage is 5.0 volts, when in reality it may be quite different. … Read the rest
Arduino’s latest incarnation – the . It is the first Arduino to use Atmel’s ATmegaXU4 series chip with built-in USB. This change is big and it has big benefits.
Early Arduinos required a serial port connection to your computer for programming. As the platform matured, the board acquired a USB to serial conversion chip. The latest version of the classic Arduino board – the Uno – still uses this method, although with the Uno a switch was made from an expensive FTDI conversion chip to using an ATmegaXU2 series microcontroller chip. This chip is a cousin to the U4 series, but lacks analog input pins.
Using a USB conversion chip was only a slight improvement over using a serial connection. It removed the requirement for a special conversion cable, but added significant cost to each and every board. With the Uno, the switch to using the ATmeag8U2 lowered the cost by a few dollars, but it seems kind of silly to use an entire microcontroller just to perform USB to serial conversion for another microcontroller of roughly the same capability.
This ironic situation is finally resolved with the introduction of the Leonardo. Not only does this AVR chip offer built-in … Read the rest
]]>I found this great video on making your own flux for soldering. Flux is a must have product when doing any electronics work, especially for surface mount parts. It helps to clean dirty parts and improves the surface tension of the molten solder so it stays on the pads instead of running between them (called bridging).
One would think that making your own solder flux wouldn’t be as good as the real thing. That may be true in some cases, but for most this at-home method is not only inexpensive but allows you to vary the thickness of the flux. Commercial flux comes in viscosities ranging from a watery liquid to a waxy paste. To understand how to create your own viscosity, let’s look at the recipe:
To make a batch, simply crush the rosin into a powder with a hammer (put into an envelope first … Read the rest
]]>His education initiative Udacity is now online. You can see the course offerings here. While it doesn’t offer many courses yet, his vision is bold, and he has the credentials to make it happen. While online learning has been with us for awhile, a major stumbling block has been certification. That obstacle will soon be overcome, and Udacity may just pave the way.
The other major innovation by Udacity is integrating the course material into real world problems and their solutions. Instead of long, isolated, boring lectures, you actually work on a project as part of the course, learning what you need to know along … Read the rest
]]>Whether you are a student, have school age children, or have used math at all in your life, you have no doubt struggled at some point with mathematics. Math is one of those things that can be difficult no matter how good you are at it. I know – I am very good in math but I still struggle.
I wanted to share two excellent resources that make that struggle much, much easier. So much easier that, for many of us, math may cease to be a struggle.
When it comes to solving and visualizing mathematical problems, good math solving software can make a difficult task significantly easier. Unfortunately, the mainstream offerings such as Maple, Matlab, and Mathematica are way too expensive for casual use. Now there is an alternative called Sage.
Sage is open source, and you can both download it (and run it on just about any OS) or run it from a browser. It has a simple interface, and is fast and powerful. This video gives a history of the project and at about 38:45, you can see a short demo.
With Sage, you don’t have to toil over an algebra or … Read the rest
]]>If you spend any time playing with Arduinos, ATtinys or looking at AVR spec sheets, you soon encounter a bewildering smörgĂ„sbord of acronyms for various communication protocols. With examples such as I2C, LIN, SPI, TWI, USI, etc., it can get pretty confusing. If you don’t believe me, just take a look communications column for Digikey’s listing for the ATmega series chips. Confused yet?
What do these terms mean? How do you choose the chip that meets your needs? How do you make use of these protocols? In this article, I take the mystery out of all these acronyms, and provide a brief overview of what they mean and how you use them in your projects. We’ll examine each of the protocols, including some of the terms that are not exactly protocols, and survey some of the software libraries available to make communications easier.
The SPI (Serial Peripheral Interface) is the protocol used by the ICSP (in-circuit serial programming) facility transmitted over the ubiquitous 6-pin (2×3 pin) header used to program AVR chips. It is useful not only for programming AVR chips, but also for other types of communications between ICs. From Wikipedia:Movie Carol (2015)
… Read the rest ]]>The
Now that you have a nice shiny PCB with your traces and pads imprinted on it, you need to drill the holes for thru-hole components and vias. The easiest way to do this is with a desktop drill press. Since I don’t have a dedicated PCB fabrication setup, I found another easy method for drilling holes at home. Harbor freight sells a 12v powered Dremel-type tool. While this tool is way under-powered for most tasks, it turns out to be a virtue when drilling small PCB holes. I simply chuck up a #60 bit and the hole already etched in the copper pad provides a nice indentation to hold the bit steady. The low power prevents the drill from getting squirrelly and jumping out of the indentation. You can probably get similar … Read the rest
]]>