nRF51 Makefile with Qt Creator

Recently I assembled a PCB I designed with the latest revision of nRF51822AC, and for my surprise the code I wrote on BLE400 development board just doesn’t work on the new platform. My main concern is that I never really figured out have to use Qt’s QBS to separate compilation of C files with GCC and CPP files with G++.In addition because I don’t properly compile the application, it seems that the G++ screws with the memory addresses regarding C code. Long story short, I realised that Qt Creator can also make use of Makefile directly in the IDE. Best part, it is extremely simple to setup, even with debugging. In this article I will go through what I changed in the nRF51 makefile to be able to compile CPP files and have two versions of release and debug for Qt Creator to compile. If you’re a hardcore compiler and makefile guru, this article probably is not for you.

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Starting with nRF51 BLE and Qt Creator

Recently I came across an interesting little ARM Cortex M0 microcontroller nrf51822, which has an integrated low energy Bluetooth (BLE)  and overall is a very capable to do other tasks besides BLE especially due to its immense FLASH memory  and RAM which is 256kb and 32kb accordingly (varies between models).  Immediately I thought of trying to make a simple smart-watch for various reasons like low energy mode, which I think was 0.1µA in sleep mode.  Only drawback compared to other ARM Cortex series microcontrollers is that it’s not really the fastest in the market, however a new one will be coming soon by first quarter of 2016, which will be more efficient, faster and overall more capable SOC. Luckily for us, their SDKs are pretty much identical, and once you learn and understand how nrf51 series SDK is structured and how to use it then switching to nrf52 shouldn’t be a problem. In any case I bought the development board BLE400 which is pictured above to play around; nonetheless I highly recommend buying the original nrf51-DK board just to support Nordic for developing an awesome micro.

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Introduction to data encryption

With the recent personal data leaks regarding celebrities, I noticed that I’ve some data on my cloud storage which should have an extra layer of protection. And NO, I don’t have any private pictures, but a document or two with some very sensitive data. You never know when you might be a victim of phishing or from a weak password. In any case, I decided to investigate some encryption algorithms. More precisely, XOR cipher, Feistel cipher and blowfish. In this article I’ll try to give some guidelines regarding these ciphers and example implementation in C++ with Qt. This article should be structured and written in a way, if you don’t know anything about cryptography, at the end you should understand most of the basic underlying theories. Also each algorithm will be introduced in a sequence where the next algorithm described will reference to previous one. Note that the intention of this article is to explain how to use them, rather than analyze their security etc.

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QHotkey is simple application for changing the MS Windows volume with your prefered keys. Also it will show nice popup with the current level of volume.

Basically, I had problems with my laptops hotkey application, it has a very long response time which renders the volume keys and all the other function keys unusable. So I decided to make QHotkey, so at least I can change volume as quick as possible. There were already some solutions available, but I found them either not looking as good as I want to or lacking key customization.

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Simple TLS/SSL SMTP client for Qt5

For one of my projects I wanted to develop a crash reporting dialog where user can enter the steps he did to crash the application and then by pressing send button the app automatically will send me user report and the log to my e-mail address. Unfortunatelly Qt doesn't have a Smtp library, and I don't want anything heavy just to send a simple string of characters through gmail smtp server.

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