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I was unexpectedly contacted at October last year by the PCBWay - a Chinese manufacturer providing PCBs, milling, 3D printing and similar stuff - that they have found my blog and are willing to sponsor my next project. I was pleasantly surprised as I thought almost nobody reads my webpage (I keep it as a hobby and to document stuff I spent a lot of time looking for solution and the others might be…
I've bought the Pokfly Extralight 6000 paragliding harness last year. When looking for reviews, I found none, so here's one... The harness is basically identical to the Karpofly Extralight 3 . A short history lesson - the Karpofly was a quite famous brand of paragliding gear, there were the first company that offered a large inflatable protection that started around pilot knees and ended up right…
The official Nordic DFU bootloader is nice, but huge, on smaller devices like NRF52811 it takes a large portion of memory, combined with a softdevice, only few kB of Flash are left for the application. But what if I don't need a full blown secure wireless bootloader and a tiny uart bootloader is all I want? And what if I could squeeze it into the 4kB MBR section of the softdevice? I was faced with…
Today's world is full of dynamic changes, software release cycle is getting shorter and shorter and everyone expect the latest features to be immediately available everywhere. It's not that hard when you are developing cloud apps, but what happens when update arrives on embedded hardware? FW upgrade theory The firmware upgrade is straightforward process, just connect the J-Link or other programmer…
Importing KiCad 3D model of the board to OnShape is quite straightforward, if you know the process, but the internet is full of complex methods that are no longer needed. After few months since the last import, I always spend some time trying to remember how to do it, so here are my notes. Export board as STEP from KiCad (File->Export->Step) Import STEP file to OnShape Select Combine to single…
I've bought the popular Quansheng UV-K5 dual band radio for my paragliding trips. It's a quite nice piece of gear, especially when flashed with egzumer alternative firmware. However, one thing troubled me quite a lot. The radio has an USB-C slot for charging, but it doesn't work with USB-C chargers. The manufacturer states the USB shall only be used to charge the radio in emergency. But the USB-C…
When I was looking for a decent hardware for a paragliding instrument I came across the E-Book readers from Rakuten called Kobo .These machines provide a decent e-ink display together with a pretty capable hardware running Linux. The main reason they are so popular among paragliding pilots is the combination of hacker friendly software and easily accessible UART port. I own an e-book reader from…
It's been some time since I bought the Cubot KingKong Mini 2 . It's been working pretty well all these years, but the battery life is not so good any longer, the phone is scratched from all sides, modern android apps are quite often very slow (e.g. windy is almost non-usable,...). So it's time to get a new phone, but which one? I quite got used to the small form factor of a 4 inch phone. The small…
During my hunt for literature about aircraft design I found several interesting old books scanned to PDF online, these raw scans are hard to read, especially when both pages are scanned on a single PDF page. I've spent some time looking for a best way to clean up the scans and transform them to a good readable form, preferably into a printable quality - that means removing all artefacts, yellowish…
The LTSpice is a great and free simulation tool for analog circuits. During design phase of my buck converter I needed to simulate the digital part, notably a fixed pulse length generator triggered by signal edge. The LTSpice is great for analog, but when it comes to digital domain, very few parts are in the standard library and very a very little support can be found online. Edge detection Let's…