Welcome to Provide Your Own - Tech


As we all know, we live in a highly technological society. While that very technology provides many blessings, it is also enslaving. We are constantly at the mercy of manufacturers, and the bulk of them overseas. We cannot build anything ourselves, nor can we even repair the things we own. What is worse is their inherent short product lifetimes, forcing us into a constant purchase cycle.
Here at ProvideYourOwn, we want to improve on this sorry state of affairs. Our goal is to pioneer techniques of building and repair for these technological marvels. As we progress together, we will gain the knowledge and tools to build, hack and repair own stuff. Manufacturing will likely never return home in the way it was. However, we can change things at a personal and local level by manufacturing ourselves.

Roll Your Own Image Recognition App

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?

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How to Get a Good Cheap 10 inch Android Tablet

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 Polaroid brand 10.1″ tablet running Android 4.0 (Ice Cream Sandwich). 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 … Read the rest

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Statistics on the Arduino (also Pic or any microcontroller)

Normal Distribution Curve

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.

Design Challenges

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

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Getting Started with Arduino

Arduino

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

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All About DC Barrel Jacks/Plugs

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

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Recovering YouTube Channel Account

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

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Choosing PCB Layout Software

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.

Online PCB Software

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.

Eagle CAD

screen shot of Eagle CADThe Eagle CAD package offers both schematic and PCB layout programs. It … Read the rest

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Reverse Polarity Protection Circuits

Reverse Polarity Alarm

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

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Secret Arduino Voltmeter – Measure Battery Voltage

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.

Motivation

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

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Arduino Leonardo versus Uno – What’s New

Arduino Leonardo

Arduino’s latest incarnation – the Leonardo is now shipping. 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 … Read the rest

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