Category Archives: Microcontrollers

nRF905 — an another module for wireless communication

You might be already familiar with different transceivers I have described here, namely LoRa module. You can read about it here (STM32 driver for LoRa) and here (Raspberry Pi driver for LoRa). Now, time have come to give nRF905 module a try. As usually, the driver alone and an example are available at my github. If you do not want to read the rest of this blog, just jump straight to nRF905 driver or the example.

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ADC is as fast as possible always the best approach?

Is as fast as possible always the best way to do things with STM?

Recently, I have stumbled upon an issue regarding ADC scan conversion on STM32 microcontrollers. I have wondered why the scan conversion was not taking place. As it turned out it did but it was not handled fast enough. In this blog post I will discuss the need to return from interrupt routine as fast as possible. However, it will not be only this one thing. Interested? So keep reading.

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LoRa driver for Raspberry Pi with Python wrapper

Here you will find my recent contribution to LoRa drivers. This post describes the LoRa driver for a Raspberry Pi SBC (Single Board Computer). Additionally, a wrapper written in Python is available making it very easy to use and prototype. Raspberry Pi gets more and more attention. Adding LoRa communication enables it to communicate with IoT devices such as remote thermometers, soil moisture sensors and many more others. You can find HAT boards thatoffer a LoRa module. Here, I describe how to connect and how to use a low-cost LoRa RFM95W module. This particular module comes with different frequency options. However, this post describes the one which uses 868 MHz frequency.

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ADC initialization order bug in CubeMX

An another bug in STM32CubeMX software. This is a perfect example where the order of called initialization functions really matters. In discussed case I will give an example where ADC was configured to go through regular conversion triggered by an event from timer and the data was transferred automatically using DMA.

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Pan Tilt Camera for Raspberry Pi with STM32 and UV4L

I would like to present a simple project which involves Raspberry Pi with a camera. Sounds boring, right! But the camera can be tilted in two axis using two servos which are directly controlled via STM32 microcontroller which in turn communicates with Raspberry Pi. Furthermore, the RPi is hosting a web server with interface to control position and speed of the camera and of course the video is streamed so you can see what is going on i.e. in your room. If you are even a bit intrigued then keep reading.

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Design of embedded system

Today, I would like to ponder on a subject of creating some measurement systems, or in more general, embedded systems. There are multiple approaches to make such a system. Let’s consider a few of them — the most popular approaches.

Embedded systems are gaining popularity by the day. Those systems are used in Internet of Things (IoT) but also in more advanced control systems. However, sometimes a need of more sophisticated system is emerging which requires more computational power. I would like to present some architectures of such systems and highlight some features of those approaches.

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Automatic router reboot device with Arduino

For quite some time I was experiencing a problem with my router. When the temperature rises behind the window it just starts to freak out. Every once two weeks or so it drops the Internet connection. Local network is still running but the incoming or outcoming connections are terminated. The only solution to this problem is to reset the router or just take out the plug and insert it after a few seconds. However, it requires me to do this every few days to make sure that the connection is good and running. I have decided to automatize the process with Arduino since it was laying around.

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Spot welder with Arduino

Some time ago I have decided to make myself a electric bike — e-bike as they are called now. However, buying a stock solution, I mean a stock e-bike, was not an option because mainly of two reasons. The stock e-bikes are quite expensive stuff, this is one. The second one is about the actual parameters of the electrical bicycle. Manufactures sell e-bikes which have limited power output to 250 Watts and are only meant to support you and not drive themselves. But wait a minute … This should be about a spot welder not the e-bike ;). Well, each electric devices ought to have a power source and this is how the idea about making my own spot welder was born.

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ST-Link-V1 — Obsoleted but not depreciated

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.

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SPL vs HAL: which one should you use (and Low Layer Library) — part 2

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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.

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Mechanical filter for UAV — damping IMU vibrations

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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.

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