August 2020


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(Deutsch) Ach Ihr schon wieder…

Sorry, this entry is only available in German.

Nicely rendered 7-segment numbers

User cbm80amiga has uploaded a nice library to render 7-segment numbers on graphical displays – especially for Arduinos. But the code can as well be used without any Arduino in the proximity, just a slight change in the library made it an universal C++ object.

Here it runs on an ATmega328 and an OLED-display […]

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Temperature measurements with an NTC thermistor

sagecell.makeSagecell({“inputLocation”: “.sage”}); Following a discussion on Facebook I put here an online tool to calculate the output of a voltage divider consisting of a fixed resistor and an NTC thermistor following a first order Steinhart–Hart equation.

The calculations are based on a voltage divider where either the voltage over the NTC or over […]

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Not WormFood’s AVR Baud Rate Calculator

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Some Toner-Transfer PCB Highlights

Some recent highlights from my home-made circuit boards using the toner-transfer method.

0.5 mm FPC breakout board

Yes, I have been told that I am crazy before… Designed in KiCAD

0.5 mm pitch FPC breakout board – before etching

0.5 mm pitch FPC breakout board – half-way etched

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Canvas: Using Python to create Calculated Questions


I just recently started with Canvas because Uppsala University has decided to use it as its upcoming LMS platform after a failed attempt with another product. Therefore I had already spent some time with Blackboard and was quite fond of the calculated questions type in quizzes. I quickly found out that Canvas offers […]

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A tiny watchdog

In a recent quick-and-dirty project with a Wemos D1 mini clone I had some problems with the reliability of the code. The ESP8266 contains two watchdogs which have the sole purpose to reset the chip if the firmware ever should get stuck. Previously I experienced these watchdogs to be too aggressive, but this was […]

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Hacking IKEA trådfri lighting automation

I recently visited IKEA again and got interested in their affordable line of home automation/LED lighting products called TRÅDFRI (meaing wireless in a play-with-words kind of Swedish). Of course there was already an internet community active in hacking these devices and I joined in.

Getting started

I installed the gateway and after pairing devices […]

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project update: a TTL/CMOS computer

Exactly one month later – our electronics course at Uppsala University just approaches its end – and I got the next shipment for my new project: 1.1 km of equipment wire.

new project: a TTL/CMOS computer

Watching Ben Eater’s youtube series on his breadboard computer based on discrete logic chips inspired me to pursue my own construction. Apart from a lack of time I also needed some more breadboards, which arrived today.

twenty new […]

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