Hall sensors

A Hall sensor is a magnetic field sensor. It was named so because of the principle of operation — the Hall effect: if we put a plate with a current flowing through it in a magnetic field, the electrons in the plate will deflect in the direction perpendicular to the current. The direction of electrons' deflection depends on the magnetic field polarity:




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Minimal Arduino DIY

It is convenient to use Arduino when you need to externalize the project quickly, not considering details. Then the idea of the project is tested, the extra functionality will hinder you.
While assembling a crawler robot, I faced with the fact that such a construction like Arduino + MotorShield + Sensor Shield plus accumulator and other components is cluttered with wires and is hardly placed on not the very tiny chassis. Moreover, there was no wish to use additional shields in order to get rid of unnecessary wires.
I had an idea to get rid of everything in Arduino that is not required in final device and at the same time to reduce the cost of the robot.


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Robotic Operating System Basics

Introduction

Hello everybody!
One day, I noticed that there is little information about Robotic Operating System (ROS) on the huddlebuddle.org. I will try to correct this mistake and popularize this wonderful product.




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Unfocused and blurred images restoration

Restoration of distorted images is one of the most interesting and important problem among image processing tasks – from both the theoretical and practical points of view. Among special cases, there are fuzzy (because of the improper focus) and blurred images. Each of you is familiar with these defects. They are very difficult to correct and just these defects are the subject of this article. The ways of how to deal with other defects (noise, improper exposure, distortion) are well known. Each photo-editor has the appropriate tools.


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Symbol recognition with Neural Networks



There are many informative articles describing the work and the principle of “neural network” notion. More articles appeared recently. Unfortunately, there are few description and analysis of practical results that were or were not received. I think for most people, as for me, it is easier and clearer to understand a real example. That is why I will try to describe almost step-by-step solution of Roman letters recognition problem + an example for self-dependent analysis in this article. Let us understand ourselves and teach the computer to recognize letters.


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Secret codes or how I wrote my application for Android

I think everyone who has a device based on the Android operating system has ever heard about «secret codes».
However there are not much articles on this subject. Yet some codes are quite powerful: for example one of the codes on my Samsung Galaxy Tab allows me to configure GPS so as to speed up the satellite search; the other code allows me to set the network connection mode stringently (GPRS, EDGE, 3G...) so as to save the battery on jumps between modes in places with unstable connection.
But I my article is not about the possibilities of the codes, I’ll tell you how to run applications using codes in the Android operating system, and how to find all the codes (and about the application that allows you to do it). And a little more about how to make an application that will respond to its code.
Further in this article you'll find 6 pictures, some code and text… The most impatient readers are welcome right to the end of the article to try the results first and then to read about the technology.


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Processor

DIY
As long as I remember, I have always dreamt of making a processor. Yesterday I finally made it. It is not too good: 8 bit, RISC, current operating frequency — 4 kHz, but it works. As of yet, in the logic circuit modeling program, but we all know: what is the model today, tomorrow will be realized in practice!


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Robot transformer Bioloid



I wish to have a robot! I wish it to entertain me … to dance itself … to cook… and to clean. As long as you continue to dream I’ll tell you about a wonderful robot that you can buy for a reasonable price now. At the same time we will look whether it could dance, and entertain, and wash socks. This robot is called Bioloid. It is manufactured by Korean company Robotis. Bioloid has an interesting feature – from a kit of parts you can assemble several different types of robots starting with a simple barrier, finishing with a robot dinosaur or an android. In fact, you can assemble your own unique robots.


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How Instagram prepared for Android app launch

As you might already know, Instagram Sold for $1 Billion to Facebook. Everybody asks – What did they pay for? Somebody compares it to the dot-com boom, but it’s only thanks to the Facebook.

During the last two years Kevin Systrom, Instagram CEO, were thinking of how to get money from his fast-growing baby, but he didn’t find a solution. And still there were rumors that he rejected the Facebook offers. Google autocompleter is used to give a “Kevin Systrom net worth” as the first option for a “kevin systrom” search term. Everything was fine even without Facebook.

They released an Android app a week ago and then were sold to Facebook for a 10-digits price. Android owners were very happy:



The developers were not: “Why is the rush? What are they paid for? I can write the same too, there’s nothing complicated and innovative in it!”

Personally I was waiting for the service to crash right in the day of releasing the app in the Google Play. But it didn’t happen. About a million of users registered within the first 24 hours. It’s not a small number, I would say.

So how has a team of 9 people managed to serve so many users and not crash?


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Rosenblatt Perceptron — what was forgotten and what was created by history?

There are already some articles about artificial neural networks. But more often it is said about so-called multilayer perceptron and backpropagation algorithm. But do you know that this variation is no better than elementary Rosenblatt perceptron?


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