Many articles here and there describe how to use OpenCV on Raspberry Pi. However, most of them are about setting up the environment by hand — meaning compiling OpenCV from sources. There are two main disadvantages to this approach. Firstly, you have to spend some time to compile it. On Raspberry Pi 3 it takes quite some time, and not mentioning the earlier versions of this mini PC. Secondly, maintaining up–to–date version requires additional time. Still, you can go for middle ground — cross–compilation that requires less time but you have to set up the environment properly. Having above in mind I will introduce you to the OpenCV with Python interface installed from pre–compiled packages. If I have your attention keep reading 😉
Yes, I am still using the practically obsoleted ST-Link-V1 on a STM32F1 disco board. It still gets the job done but regretfully it is not supported out of the box by IDE I happen to use from time to time.
When I gave a try to the AC6 (SW4STM32) I found out that, to not much of a surprise, the ST-Link-V1 is not supported. Only V2 and V2.1 are supported. Well, I decided to change that unfortunate situation because I have two of the disco boards with this debugger laying around.
I would like to present one of my latest projects which is the GSM GPS tracker. Basically, it is a device which allows to send its current position using GPS via SMS. Also it is able to log the position on a microSD card.
Some time ago I have written SPL vs HAL: which one should you use where I have focused on differences between two main frameworks for STM32 — Standard Peripheral Library (SPL) and Hardware Abstraction Layer commonly known as HAL. Since the recent post only focuses on those two sets of libraries I have decided to write some examples which can tip the scale. What is more, at the end of previous article I have asked an important question for a developer — does the STM is going to introduce us to a brand new library. Answer to this and other questions are further in this post.
Good quality estimation of tilt angles such as roll and pitch is desired when it comes to an UAV control. Without good quality signal a proper work of flight controller is nearly impossible. However, the task of filtering is not an easy task, especially when it comes to DSP (digital signal processing). It is even harder when digital filter is inadequate. In this post a mechanical filter is presented that allows to significantly improve attitude estimation in terms of roll, pitch and yaw.
There are plenty of screens for Raspberry Pi on the market. However, most of them is quite small varying from 3 to 10 inches most.
Some of those screens are dedicated ones some have HDMI interface through which you can connect it to RPi. Well, you can even use analog output to display the content of RPi’s desktop on a TV.
This is a step towards PCB prototyping. Some time ago a similar post was published but it concerned making a PCB using a thermo transfer method. If you need to prepare a PCB fast this method is probably the best choice.
What is different about the UV light method? Why is it worth your attention. The answer is simple — quality. Then how to make it? Keep reading …
There is a time in every developer’s life when the program memory is running out. If you have already experienced this problem or you are about to this article is for you!
Recently, I have come to a conclusion that it would be good to print the state of my quadrocopter on a display. The question was what kind of display should I use. I decided to give a try to a small 0.96″ OLED display with I2C interface. It is based on SSD1603 driver. You can see this display on the image above. However, there was an issue regarding the screen controller. But it was soon solved. I have come across the U8glib which is a graphic library, quite popular among Arduino users. As soon as I started to read about the library I realized that it does not support STM32, not mentioning the HAL library.
Well, I have solved that 😉
IPython Notebook is a great Matlab-like/Mathematica-like thing. You can write and run scripts written in python by using a web browser only. This post describes how to set up IPython Notebook server.
Raspberry Pi is a small factor fully-featured computer. It can be used for multiple purposes such as a controller.
In most of applications it is necessary to use some kind of communication interface. Raspberry Pi delivers, among others, UART, SPI and I2c. However, UART (serial port) is most commonly used if you just want to send some data between RPi and other devices. While using SPI or I2c in i.e. python script is rather straightforward, using serial port, or making it to work, isn’t so easy as it might seem.
Some time ago I have written a few real-time Linux drivers for Xenomai and complementary OROCOS components. But first thing first! What the heck is Xenomai and OROCOS? To keep it as short as possible; Xenomai is an open-source project which aim is to bring real-time API to Linux based system. It is an extension to the Linux kernel which makes it a hard real-time operating system. On the other hand, OROCOS is a robotic framework that brings a vast number of libraries and a toolchain to create components. What is more, Xenomai and OROCOS do play along which means you can facilitate features of both i.e. to create a hard real-time components.
If you are interested you can find the code for each driver and for each OROCOS component on my GitHub repository. Feel free to fork!
Below are direct links to the repositories:
Some time ago I decided to give KiCAD a shoot, actually it was a second attempt. For a long time I have been using Eagle CadSoft but now the disadvantages tip the scale. Also now, KiCAD has a crazy new feature which is called interactive routing. However, KiCAD is not quite straightforward and it requires some getting use to. One thing that struck me was the necessity of Internet connection. When you want to connect components with appropriate footprints using CvPcb it scans the library paths. And it is here where the problem starts…
Recently I have written a short post about the HAL library created by STM32. The HAL is gaining popularity among hobbyists and is more and more frequently used. However, when you would like to use it for something else than just basic stuff like generating PWM on digital output you have to write it by yourself. Not so long ago I had to use SD card in one of my projects. It turned out that there is no driver for FatFS based on HAL – at least there was not. I decided to write the driver and here you can read about it…
There is an unending dispute about which library should you use when writing an application for STM32 microcontroller. Actually, there are at least three choices which you should consider. In this post I will highlight the advantages and disadvantages of each approach which can be considered when writing software for ST microcontrollers.