Pull to refresh

All streams

Show first
  • New
  • Top
Rating limit
  • All
  • ≥0
  • ≥10
  • ≥25
  • ≥50
  • ≥100

CodeIgniter 4. Prelude to PHPUnit

PHP *CodeIgniter *
Tutorial

Thanks for your feedbacks

I thank the members of the Habr community for their benevolent attitude to the article by the author «Speed Dating with the CodeIgniter 4 on GitHub» in the form of votes and comments.

The friendly attitude to the author prompted him to continue developing a topic dedicated to PHPUnit as part of CodeIgniter 4.

Install Xdebug on XAMPP (Windows 32-bit (x86))

1. Why Xdebug? In file «appstarter/tests/README.md» in the «Requirements» section explicitly states: «You also need to install XDebug to successfully calculate code coverage».

Read more
Total votes 1: ↑0 and ↓1 -1
Views 481
Comments 0

Is PHP compilable?! PVS-Studio searches for errors in PeachPie

PVS-Studio corporate blog PHP *.NET *Compilers *C# *

PHP is widely known as an interpreted programming language used mainly for website development. However, few people know that PHP also has a compiler to .NET – PeachPie. But how well is it made? Will the static analyzer be able to find actual bugs in this compiler? Let's find out!

Read more
Total votes 2: ↑2 and ↓0 +2
Views 258
Comments 0

Using a headless browser for WebRTC load tests

Flashphoner corporate blog System administration *Working with video *IT Infrastructure *DevOps *

In the previous article we went over a load test whose data could be used to choose a load-appropriate server. In the course of the testing, we would publish a stream on one WCS, and we would pick up that stream several times using a second WCS. The acquired results could be used as a basis for decisions on server operability.

Some would (justly) have concerns regarding the possible biases in such a test — after all, one of our servers was used to test another one of our servers. Could it be that we were using a specially optimized code that skewed the results in our favor?

Read more
Total votes 1: ↑1 and ↓0 +1
Views 641
Comments 0

Controlling Brushless Motors from Windows

Robotics development *Development for IOT *Development for Windows *Robotics IOT
Tutorial

In this video, we will look at how to connect brushless motors to a Windows computer via USB. We are going to connect a network of Servosila brushless motor controllers to the computer. The other option is CANbus interface, but we will look at CANbus in a dedicated video. A regular USB cable is used. Note that the USB cable is not used to power the controller and its motor.

The first brushless motor controller in network appears to Windows as a Virtual COM port. Once connected via USB, it can be found in a general list of devices in the Window's "Settings" window. Up to 16 controllers can be connected this way via a single USB cable to the same control computer or a PLC. If one of the interconnected brushless motor controllers is connected to a computer via USB, then that particular controller becomes a USB-to-CANbus gateway for the rest of the network.

If your computer happens to have more that one serial port, you may wish to check a COM port's number assigned by Windows to the controller. Then, you pick this COM port in a drop down menu in the Servoscope software, and click Connect. If the COM port is not listed in the drop-down menu, click the Refresh button. If everything is good, the controller appears in a list of devices. Double-click to open up a control and configuration window.

Video & Read more
Total votes 5: ↑3 and ↓2 +1
Views 541
Comments 0

PVS-Studio 7.14: intermodular analysis in C++ and plugin for JetBrains CLion

PVS-Studio corporate blog

0854_Release_714/image2.png


The PVS-Studio team is increasing the number of diagnostics with each new release. Besides, we are improving the analyzer's infrastructure. This time we added the plugin for JetBrains CLion. Moreover, we introduced intermodular analysis of C++ projects and speeded up the C# analyzer core.

Read more →
Total votes 5: ↑5 and ↓0 +5
Views 464
Comments 0

System-on-Chip bus: AXI4 simplified and explained

FPGA *Robotics development *Programming microcontrollers *Circuit design *Manufacture and development of electronics *

Protocol AXI4 was developed for High-bandwidth and low latency applications. It is designed to allow communication between master and slave devices. Master is typically a DMA or CPU and slaves are DRAM controllers, or other specific protocol controllers: UART, SPI, and others. Sometimes one component can implement multiple instances of this protocol. Usually, a prefix is used to differentiate between multiple AXI4 interfaces.

For example, Ethernet MAC can integrate DMA and slave interface used to command MAC. MAC can accept commands on the slave interface that contain data about the location of the next ethernet packet and MAC can start fetching this packet using the separate master interface instance.

This article was motivated by common design mistakes AXI4 designers make when they are designing their Digital IP. (Looking at you Xilinx)

Read more
Total votes 10: ↑10 and ↓0 +10
Views 1.3K
Comments 0

Private party protocol: how to distinguish friends and foes using cryptographic tools

Information Security *Cryptography *Network technologies *
Tutorial

ENCRY presents a new interactive identification protocol aimed at controlling the access of selected users to various resources.

Close your eyes and imagine Nice, a luxurious estate whose extravagant owner throws epic parties with jazz and fireworks every weekend.

To attend such a party is a lot of the elite. Invitations are sent out in advance, and guests do not know the names of other invited persons. The owner of the estate, the mysterious Jay Gatsby, an eager luxury-lover, values ​​privacy so much that he is not ready to entrust the list of invitees to anyone, not even his buttress. Moreover, the owner of the estate would like the guests not to reveal their names when entering the property. After all, there may be the mayor of the city, or the chief prosecutor among them, and they would like to keep their visit secret. Unfortunately, the owner of the estate himself is so busy that he cannot independently check each guest at the entrance, especially since there are several access roads to his house. How could he solve this problem?

Read more
Total votes 2: ↑2 and ↓0 +2
Views 651
Comments 0

Doubling effective digitization frequency by multiple pass approach, is it possible?

Algorithms *Programming microcontrollers *DIY

As already described in the previous article, in the process of reworking the DSO138 oscilloscope toy, the idea arose in the DSO303 firmware at some point to try to double the maximum sampling frequency to achieve scanning times of 500 and 200 nanoseconds per cell. In fact, for the STM32F303, the theoretically maximum achievable sampling rate from the point of view of the ADC input, and this is determined by the minimum opening time of the ADC sampling unit, which in our case is 1.5 clock cycles x (1/72 MHz) = 20.8 nanoseconds, is 48 MSPS (millions of counts per second). However, with the parallel operation of 4 ADCs at 6 MHz, it is possible to achieve only 24 MSPS due to the limited speed of the ADC.

Let's imagine that we are considering correctly-periodic signal, which is also constant, i.e. it does not experience fluctuations in frequency and amplitude over time. Is it possible to somehow digitize it not in one, but in several passes, thereby increasing the effective sampling frequency? 

Read more
Rating 0
Views 439
Comments 0

DSO138 upgrade

Programming microcontrollers *Circuit design *DIY Electronics for beginners

On Ali, an interesting toy – an oscilloscope called DSO138 is sold for a very inexpensive price. It has already gained quite a lot of popularity among electronics lovers, but the parameters of this device, alas, allow it to be more or less fully used only for debugging very low-frequency circuits. Actually, it is not positioned as a tool, but rather as a DIY-kit for novice electronics engineers.

This "toy" oscilloscope is assembled on the STM32F103 microcontroller, and with a fairly competent circuit design of the digital part, the presence of a fairly decent 320X240-dot color display, and not the most rotten analog path, everything, alas, is ruined by very weak ADCs on board the 32F103. The claimed band of 200 kHz can be recognized as such only with a very large stretch. Yes, it will show the presence or absence of a signal with such a frequency, but it will not be possible to really look at something beyond this.

At the same time, the 103-series has a slightly more powerful brother - the STM32F303, it is almost completely compatible with the legs, but it is significantly better in terms of the parameters we are interested in, there are 4 ADCs on board with a conversion frequency of 5 MHz (6 MHz with a 10-bit resolution). In this scenario, if you use all 4 ADCs in parallel with a 10-bit resolution, you can get a effective resolution of up to an honest 24 MSPS (millions of samples per second). The microcontroller is also inexpensive; you can easily find it on the same Ali for very reasonable money again. It is clear that the idea to change the microcontroller arose almost immediately after I tried this DSO138.

At the same time, if upgraded the toy can turn out to be a completely full-fledged tool that even professionals, not just novice amateurs, could already use. With these thoughts in mind, I decided to try to do something with a Chinese toy in my free time.

Read more
Total votes 5: ↑5 and ↓0 +5
Views 820
Comments 0

Controlling Brushless Motors using Raspberry PI

Robotics development *Development for IOT *Development for Raspberry Pi *Robotics IOT
Tutorial

In this video tutorial, we will control a pair of brushless motors from a Raspberry PI computer. We will use one of the computer's USB ports to connect a network of brushless motor controllers. We will power the computer, the controllers, and the brushless motors using a single battery, similar to a autonomous vehicle design.

The first motor is an outrunner type, a kind of what you would use for a vehicle propulsion. The bigger motor comes with a quadrature encoder which means it can be used as a powerful servo.

I made a cable to power my set up. On one end, the cable has a socket for plugging the battery. The cable splits into a two parallel parts to power the controllers, and the Raspberry PI. The bottom part of the cable further splits to power a pair of brushless motor controllers.
By the way, the controllers need 7 to 60 Volts DC. I put proper connectors at the ends of the cable, so that I could just plug it into the controllers.

Servosila brushless motor controllers come in rectangular or circular form factors. The controllers have USB and CANbus ports for connecting to control computers such as Raspberry PI.

Video & Read More
Total votes 6: ↑5 and ↓1 +4
Views 816
Comments 0

PVS-Studio team's kanban board. Part 2: YouTrack

PVS-Studio corporate blog Development Management *Project management *

Hello everyone! Welcome to the second part of the PVS-Studio Team's Kanban Board story. This time we'll talk about YouTrack. You'll learn why we chose and implemented this task tracker and what challenges we encountered. We don't want to advertise or criticize YouTrack. Nevertheless, our team thinks JetBrains has done (and keeps doing) a great job.


0853_Kanban_YouTrack/image1.png

Read more →
Total votes 4: ↑3 and ↓1 +2
Views 367
Comments 0

Optimization of .NET applications: a big result of small edits

PVS-Studio corporate blog .NET *C# *

0852_NETAppsPerf_MinChangesMajorRes/image1.png


Today we're going to discuss how small optimizations in the right places of the application can improve its performance. Imagine: we remove the creation of an extra iterator in one place, get rid of boxing in the other. As a result, we get drastic improvements because of such small edits.

Read more →
Total votes 6: ↑4 and ↓2 +2
Views 825
Comments 0

Choosing a server for 1000 WebRTC streams

Flashphoner corporate blog System administration *Working with video *IT Infrastructure *DevOps *

In any project, a great deal of importance is placed on the selection of server hardware and WebRTC streaming is no exception. One of the key principles of such a selection is balance – the hardware should be powerful enough to handle the streams with no drops in quality, but not too powerful so as to waste resources. So, how does one choose the right server?

Read more
Total votes 3: ↑3 and ↓0 +3
Views 610
Comments 0

VSCode: how to view reports of static analyzers that support SARIF

PVS-Studio corporate blog Visual Studio *

People increasingly start optimizing the process of finding code errors using static analyzers. Nowadays, we can choose from a variety of products to view analysis results. This post covers the ways how to view an analyzer report in the most stylish and feature-rich IDE among multifunctional ones – VSCode. The SARIF format and a special plugin for it allow us to perform our task. Keep reading to find out about this. Let's get going!

Read more
Total votes 3: ↑3 and ↓0 +3
Views 462
Comments 0

How to see and save Instagram requests on an android device

Reverse engineering *
Sandbox

Once I was asked to save a traffic dump of an Instagram app while viewing one particular user profile. Simply saving the traffic dump on the router didn't make sense because the app used TLS to communicate with the server. Existing solutions didn't work because they worked with an older version of Instagram.

Below I will describe how I managed to do it myself using mitmproxy, ghidra and frida.

Read more
Rating 0
Views 1.1K
Comments 0

Improving the quality and formatting of the code in the TypeScript

JavaScript *Node.JS *Start-up development TypeScript *
Sandbox

With the help of the ESLint and Prettier features, you can automate the formatting of your code, make it more expressive and accurate, correspond to specific rules, and avoid errors and bottlenecks even before uploading the code to the shared source storage...

Read more
Total votes 1: ↑0 and ↓1 -1
Views 810
Comments 2

Unfinished startups — the AELITA project

AR and VR Medical gadgets Lifehacks for geeks
Recovery mode
Translation
image

Back to the list
Introduction


I spent a long time thinking about whether or not I should write stories like this from the lives of innovators. After all, revealing the essence of unfinished project means you can lose the very foundation of the project, its pizazz and even its know-hows. Moreover, that's already happened to me in one of my projects from 10 years ago. I'm not going to give an example of this situation, it's already been talked about in another article. The story is on this site: intersofteurasia.ru/novosti/605/606.html.

However, considering that modern progress can't be stopped and that sooner or later some curious minds will get to the bottom of a technical solution for something like this, I decided to lift the veil a little bit on the secret life of an innovator.

Be it noted that this unfinished project with the provisional name AELITA is somewhat of a cross between biomedicine, electronics, psychology and much more, so getting it done isn't exactly easy. After all, for projects like this you need enthusiastic people working in different, sometimes diametrically opposed fields of science and technology, but an interdisciplinary approach is capable of giving surprising results if projects like it are completed.
Read more →
Rating 0
Views 460
Comments 2

Go Code Generation from OpenAPI spec

Programming *Go *
Tutorial

OpenAPI specification


One of the nicest features of Go is the power of code generation. go generate command serves as a Swish knife allowing you to generate enums, mocks and stubs. In this article, we will employ this feature to generate a Go code from OpenAPI specification. OpenAPI specification is a modern industrial standard for REST API. This standard has fantastic tooling support and allows you to conveniently render and validate the spec. We are going to befriend the power of Go code generation with the elegance and clarity of the OpenAPI specification. In this way, you don't have to manually update the Go boilerplate code after every change in the spec. You also ensure that your docs and your code are a single entity, as your code is being begotten from the docs.


Let's start dead-simple: we have a service that accepts order requests. Let's declare endpoint order/10045234 that accepts PUT requests, where 10045234 is an ID of a particular order. We expect to receive an order as a JSON payload in the following format.


    {"item":  "Tea Table Green", "price":  106}

How can describe this endpoint in the OpenAPI spec?

Read more →
Total votes 3: ↑3 and ↓0 +3
Views 717
Comments 0