Writing a Quick and Easy Thread-Monitor (Watchdog) in Python [shorts #1]

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A thread-monitor, often also referred to as a watchdog, is extremely helpful when building multi-threaded and reliable applications. In its simplest form, a watchdog should detect when one or more threads hang or crash, and it should restart the problematic threads if necessary. Depending on your use-case, you could implement this helper in a variety of ways, and you could add many more features such as a heartbeat function that allows each thread to report its progress to the monitor.

Continue reading Writing a Quick and Easy Thread-Monitor (Watchdog) in Python [shorts #1]

Write better looking console applications using ANSI escape codes

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Console applications are a great thing: They usually solely focus on getting things done. That, however, often also means that the user experience can come short. While I don’t have a problem with a simple text-only menu, it can often scare away new users. But there’s a way to easily style your console applications so that they can have something that you could call a primitive GUI:

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How to use Websockets to control an ESP8266 and a Raspberry Pi with a web browser

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For a current project of mine, I had to evaluate how high the latency is when using websockets. In my case, I wanted to use a small single board computer as the server and any device, that can run a web browser, as the client. This tutorial illustrates how a Raspberry Pi and an ESP8266 can be used to act as a websocket server that can be controlled with a standard webbrowser.

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Low latency and high FPS camera stream with a Raspberry Pi

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I just saw that two very good sources, that both had an article about this topic, have gone offline without an archived version. And because I continued my work on a robot that is controlled by a Raspberry Pi, I had to figure out how to create a low latency and high FPS stream from the Pi’s camera that can be viewed in a web browser again.

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DIY electronic riddle advent calendar

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Oh yes, Christmas! It’s almost that season of the year again. And to shorten the time between the 1st of December and Christmas Eve’, I thought about a bit more interesting advent calendar than one, that only has chocolate in it. This electronic advent calendar offers a riddle that you can create for a loved one or a friend and give it to them so they can try to solve it before Christmas arrives. It offers a clue every day and it presents all unlocked clues on a website that runs on the device itself. The only two things it needs to work is a power supply and a WiFi network it can connect to. And the best thing is: It is really simple to build and it can be re-used every year and it can also be used for other occasions (for example Valentine’s Day)! Continue reading DIY electronic riddle advent calendar

How to use hardware PWM/CLK to get exact timings on a Raspberry Pi

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Introduction

This might not be a common issue, that hobbyists run into when creating their projects, because usually the software PWM, offered by the raspberry pi’s RPi.GPIO-Module, is exact enough for dimming some lights or controlling dc-motors. But for real-time and time-critical applications, this is actually an issue: Continue reading How to use hardware PWM/CLK to get exact timings on a Raspberry Pi