[4] Communication instruction design – smart car under Pcduino platform

[4] Communication instruction design – smart car under Pcduino platform

3 months ago (03-27) Views: 16 Comments: 0

First, the command packet protocol design In the remote control smart car system, the remote client controls the smart car through command communication.In the design of this paper, only the speed direction control instruction is involved. In order to consider the scalability of the system: because there may be more types of instructions for subsequent requirements, this article has designed the instruction code for the instruction data. The instruction consists of the instruction code and the instruction data area; consider To the client and the server to better handle the instruction, the instruction word length is 32 bits, and the int data type word length is equal to the int data processing when the server and the client socket socket to send and receive data .In studies similar to this design, char characters are often used to control the direction. I think it is inadequate. Because a char type can quantify and access data, it can save network traffic and ensure real-time performance.   Instruction code (4bit) Command data area (28bit)   When the command code is 1, the speed direction control command of the sending vehicle is indicated, and the command data package is a schematic diagram:   0

[1] Overview – smart car under the pcduino platform

[1] Overview – smart car under the pcduino platform

3 months ago (03-19) Views: 19 Comments: 0

  This article uses a Freescale automotive model equipped with a DC motor and an analog circuit control servo to simulate a real car.The PcDuino development board on the car model is equipped with the Ubuntu operating system and is compatible with the Arduino extension to implement hardware control. The binocular camera connected to the development board can capture two channels of video and transmit it in real time over the network to provide support for binocular vision ranging. At the same time, it has developed a "Visual Aided Navigation System" Android-side application that can remotely view the live conditions around the smart car and control the car. I. Introduction The emergence of Arduino's open source hardware platform has greatly improved the efficiency of hardware development. Even software programmers without any hardware infrastructure can write simple code to control the hardware by using the open source library provided by Arduino, greatly reducing the use of Arduino platform. The difficulty of this design. Arduino also offers a variety of expansion boards. The Arduino ecosystem is very powerful. Many developers have developed peripheral expansion modules for Arduino, such as motor modules, infrared control modules, and touch modules. These modules greatly enhance the

Emmet gracefully builds the Html skeleton

Emmet gracefully builds the Html skeleton

2 years ago (2016-12-05) Views: 0 Comments: 0

I once saw an academic who entered a strange code on PHP-Storm. When he pressed the Tab key, something magic happened. If HTML is also a programming language, it is privately thought that Html will be the most popular programming language we have come into contact with.Someone may not know what HTML (Hypertext Markup Language) is, but when he first opened the web browser to browse the web in his life, he and the HTML began to humble.... But when he didn't know it was very colorful. Behind the web page is the silent support of the HTML language; HTML+JS+CSS is the front-end three languages.If we compare web pages to humans, HTML gives people skeletons, CSS unknowns give flesh and blood, even clothes and clothing, and JS gives him the soul of sports. This article starts with HTML. The basic knowledge of HTML is beyond the scope of this article. You know, Google.Here, I mainly talk about how to quickly build up the skeleton of HTML. Thinking of HTML as a skeleton is not my whim. I'm just telling myself to write HTML pages with a sense of framework.It goes without saying that my previous HTML code was patchwork.Wherever it

Ubuntu first saw

Ubuntu first saw

2 years ago (2016-12-03) Views: 4 Comments: 0

One, UI When I was freshman, I liked to play with various systems, so I had tasted before the company asked to experience the Ubuntu system.For a novice user, the initial contact with an operating system is its UI. My first impression of the Ubuntu system is a better-looking Linux system. It is similar to the Mac system, but no Mac looks good.For users who are accustomed to the operating system of Windows, I still prefer the UI of Windows 7 and Windows 10.Do not know the reason of the system itself or ubuntu PC graphics card support is not a good reason, there is always a Ubuntu interface rendering is not enough delicate feeling. In any case, Ubuntu is more attractive to the Linux system it is exposed to, and the support for visual operations is also better.If you still complain that Ubuntu is not as beautiful as windows, try installing a KDE or GNOME desktop environment on centos and you will find out how beautiful Ubuntu is. Second, the Linux distribution The most basic definition of Ubuntu is the Linux distribution.In the past, I always heard about the word release, but I never knew what the distribution meant.So

Gradle using configuration files to control the version of build tools

Gradle using configuration files to control the version of build tools

2 years ago (2016-08-12) Views: 5 Comments: 0

Because Android studio and Android related SDKs and build tools have extremely fast update speeds.Modifications to relevant versions are sometimes more sensitive, especially in team projects where individuals modify the version of the relevant tool locally and accidentally submit it to a remote code repository. Others often have problems updating.The version field in the Android studio project file is very scattered. When the SDK environment changes, it is still more troublesome to modify.This article uses configuration files to centrally control build tool versions. The gradle.properties file defines version information and assigns values ​​in the project root directory   Reference gradle variable where version information is used Dependencies Build.gradle(project) Build.gradle(module)

AndroidStudio code obfuscation and NDK prevention apk decompilation

AndroidStudio code obfuscation and NDK prevention apk decompilation

2 years ago (2016-01-09) Views: 4 Comments: 0

Code obfuscation What is code confusion Java is a cross-platform, interpreted language in which Java source code is compiled into an intermediate "bytecode" stored in a class file.Due to cross-platform requirements, Java bytecode includes a lot of source code information, such as variable names, method names, and access to variables and methods through these names. These symbols carry a lot of semantic information and can be easily decompiled to Java. Source code.To prevent this, we can use the Java obfuscator to confuse Java bytecode. Obfuscation is to reorganize and process the released program, so that the processed code and the pre-processing code accomplish the same function, and the obfuscated code is difficult to be decompiled. Even if the decompilation is successful, it is difficult to obtain the true semantics of the program. .The confusing program code still complies with the original file format and instruction set. The execution result is also the same as before, but the obfuscator changes the names of all the variables, functions, and classes in the code to short English letter codes. With the corresponding function names and program comments, it will be difficult to read even if it is decompiled.At the same time, confusion is

Android implementation opens a specified link to call other applications

Android implementation opens a specified link to call other applications

3 years ago (2016-01-01) Views: 1 Comments: 0

Some websites have set a link on the page to jump to their official app, such as JD. Recently, I added this feature to Wang Baiyuan’s blog client to open links on web pages and call my client to open related articles. .The following is the implementation method: Android implementation opens a specified link to call other applications Add an intent-filter tag in the AndroidManifest.xml manifest file of the Activity that needs to jump to the specified link, and set the scheme, HOST, and other attributes as shown in the following example. And made a web page test successfully:  

Multi-engine search box with auto-hint support

Multi-engine search box with auto-hint support

3 years ago (2015-12-30) Views: 3 Comments: 0

After using the online open-source navigation station source code to create my navigation page "hundred yuan navigation", I always feel that it lost a very important thing in the navigation site - the search box.So the extremely guest has added the function of the search box for their navigation station, supports Baidu search, good search, geek search, CSDN search, dandelion PT search, etc. (can easily increase the code expansion), in addition to the site interface using the online code, The js code of the logic processing part is entirely realized by me. Html code: The following is the html part of the search box interface, CSS is not posted below, if you need to leave a message: Javascript code To think of the search box as supporting multi-search engine switching, you first need to grasp the URL parameters of the search engine's search keywords, and check that there are several GET parameters (search engines generally use GET values). For example, the following is the search engine search for Wang Baiyuan’s The URL of the blog's results page: https://www.baidu.com/s?ie=UTF-8&wd=%E7%8E%8B%E6%9F%8F%E5%85%83 ?Ie followed by the encoding format, wd is followed by the URLEncode encoding of the searched keyword. So just make a form,

Traffic Keywords Link Pages Boost Baidu Weights

Traffic Keywords Link Pages Boost Baidu Weights

3 years ago (2015-12-20) Views: 2 Comments: 0

Baidu search rankings often change according to the size of the traffic that the page search enters. If many people will enter the same page for a keyword, Baidu will think that this page can solve this problem well, so that this page will be searched for in this keyword. It is in front of other pages.In the backstage of Baidu webmaster platform, we can know what keywords are searched by Baidu and whether they have entered our webpage.We can do this by making a page that contains all the URLs for those keywords. After visiting, we can access our website to improve our website ranking. Traffic Keywords Link Pages Boost Baidu Weights The following code is a traffic keyword link page I wrote, which is all my Baidu keywords.We occasionally click to improve the corresponding keyword rankings.The usage method is to export Baidu traffic keywords in a keyword.txt file with one keyword per line. The file path is the same as the following PHP code file.  

Download resources on Dandelion PT via NWPU-VPN

Download resources on Dandelion PT via NWPU-VPN

3 years ago (2015-09-17) Views: 3 Comments: 0

In September, we entered the junior season.Say goodbye to the Chang'an campus, say goodbye to Zhong Nanshan, which is opposite day and night, and bid farewell to the outdoor flowers of birds singing in the ear. We have come to the friendship campus.We have finally moved into the city from Dashan. The consumption in the urban area is high, but the standard of living has dropped a lot.The IPV6, which has been accompanied by us for two years and gave us countless wonderful experiences, has also fallen by the wind. Moving into the garden, there is no IPv6, and the dandelion of IPv4-supported NWTC has also issued a order to us: your IPv4 address 113.200.156.51 is not an NWPU IP. In order to solve the problem of downloading resources on the campus PT network, there are many legends. Such as IPv6 tunnels, these methods have not been tried by the very guests, but very successful guests successfully use the NWPU open VPN service to successfully download resources on dandelion. NWPU's campus network VPN service facilitates the staff of the Shanghai University of Technology to access information resources on campus outside the school (such as Fuxiang Office, Yuxiang Network, and library

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