c++

134 Articles

Under-desk RGB Keyboard Lighting

November 11, 2010 by 34 Comments

[Jay Collett] was having trouble seeing his keyboard when the room was dim. But throwing a light under the desk just didn’t seem cool enough. Instead he built an RGB light board that is controlled by his desktop. The board is based around an ATmega328 with the Arduino booloader. He etched a single-sided PCB to connect it to a group of five RGB LEDs, with a programming header for an FTDI cable. The board communicates with a PC via serial connection, with a C# control application that [Jay] coded to control the color. We’ve embedded a couple of videos after the break but check his page for a package of code and hi-res pictures.

If you want something cool that’s a little bit less work to build check out the EL-wire keyboard from this links post.

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AVR Programming 03: Reading And Compiling Code

November 5, 2010 by 41 Comments

In the last installment of our tutorial series we built a simple circuit on a breadboard and programmed an ATmega168 to make it run. That proves that you know how to follow directions, but the eureka moments of doing everything yourself are on the way. This time around you will get down and dirty with the datasheet, learning where each line of the sample code came from, and give your recently installed compiler a test drive. We will:

  • Talk about bitwise operators and how they work when coding for microcontrollers
  • Discuss C code shorthand
  • Review the sample code from Part 2 and talk about what each line of code does
  • Learn to compile code

If this is the first you’ve heard about our AVR Programming series, head back to Part 1 and start from the beginning. Otherwise, take a deep breath and we’ll being after the break.

Series roadmap:

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C Sharp Development 101 – Part 2: Toolbox Controls

October 15, 2010 by 29 Comments
In this tutorial we are going to start finding out more about the toolbox we utilized in the previous tutorial.  The Controls available in the toolbox are quite extensive and allow users to simplify a variety of everyday tasks such as manually creating and instantiating a textbox on a windows form.  At the end of this tutorial you should be comfortable finding Controls in the Visual Studio Toolbox, alter or produce code to link tools together using event handlers and ultimately get a better sense of Visual Studio, it’s layout and how to easily navigate it.

Open Call: Send Us Your Debounce Code

October 13, 2010 by 75 Comments

If you’ve ever designed an embedded system with at least one button you’ve had to deal with button debouncing. This is also know as contact bounce, a phenomenon where a button press can be registered as multiple button presses if not handled correctly. One way to take care of this is with a hardware filter built from a resistor-capacitor setup, or by using a couple of NAND gates. We find that [Jack Ganssle] put together the most comprehensive and approachable look at contact bounce which you should read through if you want to learn more.

We’re interested in software solutions for debouncing buttons. This seems to be one of the most common forum questions but it can be hard to find answers in the form of reliable code examples. Do you have debounce code that you depend on in every application? Are you willing to share it with the world? We’d like to gather as many examples as possible and publish them in one-post-to-rule-them-all.

Send your debounce code to: debounce@hackaday.com

Here’s some guidelines to follow:

  • Please only include debounce code. Get rid of other unrelated functions/etc.
  • You should send C code. If you want to also send an assembly code version that’s fine, but it must be supplementary to the C code.
  • Please comment your code. This will help others understand and use it. You may be tempted to explain the code in your email but this info is best placed in the code comments
  • Cite your sources. If you adapted this code from someone else’s please include a note about that in the code comments.

As an example we’ve included one of our favorite sets of debounce code after the break. Please note how it follows the guidelines listed above.

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C Sharp Development 101 – Part 1: Hello World

September 30, 2010 by 50 Comments

In this tutorial we are going to get up close with the Visual Studio 2010 environment. We will learn how to make a console application as well as a form to display our hello world applications.  This will give us an opportunity to view 2 types of solutions of the many available in Visual Studio.  We will start making the console application first then progress to the forms application.

First we must  understand the development environment we are going to use.  On the far left side is the toolbox panel.  This panel gives us access to a lot of controls  that can be used by the Windows Forms.  Next is the Solution Explorer that will allow us to navigate the projects and files we are going to create in this Solution.  The Properties panel is directly under my Solution Explorer and will allow us to change properties of controls and of the form we will create later on.  If any of these are not being displayed they can be retrieved from the View menu at the top under Other Windows.  For more information on the Visual Studio IDE visit MSDN and search for the specific questions you are having.

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Auxiliary Scoreboard Reads Status Directly From Memory

September 13, 2010 by 28 Comments

[StaticChanger] built a scoreboard to display his kill statistics from Halo for the PC. Yes, we’ve seen kill counters before, but we like the way that he gathers the data. This project is reading the score directly from an address in memory.

Using a program called Cheat Engine, the memory used by a program can be sniffed. After a few passes, the program will help you find a static memory address for your desired data. Once you have that it’s just a matter of using a pointer to that address in your desired programming language. In this case, a C# program polls the value and instructs an Arduino to display the value on a couple of 7-segment displays. Voila, the number appears next to your screen as you see in the image above.

C Sharp Development 101 – A Tutorial Series

September 3, 2010 by 107 Comments

In this tutorial series we are going to look at C# Development using the Visual Studio 2010 Express editions.  This will take you from the basics of installing Visual Studio 2010 Express, to the Object Oriented Programming style associated with C# and other languages, dabble in some database access (Access & SQL Server Express) and finally, design a project that will pull all of our knowledge together into a final solution.