• JWT claims explained - registered, public and private

    JWT, the JSON Web Tokens are a standarized (RFC 7519) way of passing the user’s identity between microservices. Internally, the JWT payload is just a JSON with pertially standarized fields. They are called claims. Some of the claims are defined in the RFC 7519 while some are free to use and abuse freely. The video below exmplains this topic.

    In general, claims are divided into 3 categories:

    • registered - they are defined in the RFC and have to be used accordingly
    • public - not defined by the RFC, but their meaning and usage is defined in the Public registry of JWT claims
    • private - can be used freely, but might not be compatible with other implementations
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  • What are JWT tokens? Modern authentication and authorization for microservices

    JSON Web Tokens, or JWT, are a great and modern way to handle User identity, authentication, and authorizations. All modern user management systems like Keycloak, AWS Cognito, or Auth0 are issuing JWT tokens! And remember, with microservices, session-based authentication and authorization is a no-go.

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  • NFTs does not work like you think they do | NFT for beginners

    Have you heard about this picture of a monkey sold as an NFT for more than 2 million dollars? Crazy. Everybody gets that NFTs (Non Fungible Tokens) are secure and work based on blockchain. Most don’t get what exactly that means. Because no, having an NFT is not proof that you legally own something. Or that your token is the only “content” in existence. It works in a slightly different way!

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  • How BAD are cheap 18650 Li-Ion batteries from China?

    China is a magical place where you can get everything for a fraction of a price. Like 10000mAh 18650 LiIon batteries for $1.5. Of course, we have to begin with a note, that there are no 10000mAh 18650 batteries! Technology does not allow for such energy density. And if they would exist, they would not cost $1.5. Closer to $15. Anyhow, I’ve bought a couple of cheap 18650 on Aliexpress and tested them with a DIY OpenSource OpenHardware Arduino-based battery discharger.

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  • Colorfabb LW-PLA Light Filament

    There are many 3D printing filaments to choose from. Each of them has its own specific features: PLA is simple and easy to use, PET-G has more temperature resistance, Polypropylene can be bent and TPU is indestructible.

    If you look for a filament that gives the lightest prints, there is only one option: foamed PLA filaments called LW-PLA. Today let’s take a look at the LightWeight PLA (LW-PLA) from Colorfabb.

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  • BlHeli Motor Timing Explained

    What is motor timing? You can change it in the BlHeli configurator, but what does it do? Many tutorials say that you should increase Motor Timing. What is the gain of doing so? And why is it in degrees (at least in BLHeli_32)? The short answer is: higher timing equals slightly more torque but less efficiency.

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  • Can you sell Open-Source software?

    Many companies are afraid of Open-Source software. There are myths and misunderstandings. One of them is: can I sell open source (GPL, MIT, Apache License) to my clients? The answer is both yes and no.

    There is nothing that prohibits issuing an invoice for Open-Source software. However, license transfer can be tricky. You will learn more in the video below.

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  • GoPro Media Mod microphone quality

    GoPro makes great action cameras. Small, tough, with image stabilization and other cool features. For some time now, they can be used also for more “professional”, cinematic purposes. I’m recording quite a lot of my videos with the help of GoPro Hero camera. Previously with Hero 7 and Hero 8. Now with the Hero 10.

    The problem with the latest Hero cameras is that they do not have the HDMI out or microphone port. To have them, you have to buy the Media Mod.

    GoPro Hero 10 with Media Mod, RODE microphone and LED light

    GoPro Media Mod has its own microphone that is supposed to be better than the one built-in into the camera itself. But is it?

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  • GoPro Hero 10 Black

    GoPro releases the new action camera every year. Usually around September. This year was no different and only a few weeks ago we’ve been presented the anniversary release: GoPro Hero 10 Black.

    I purchased my Hero 10 a few days after the premiere. My target usage for this GoPro was: I need a smaller camera to record videos on the outside for my YouTube channels and maybe a better one to put on my FPV drones. One week later I know everything. For the first of those purposes Hero 10 is dope! For the second one, not so much.

    GoPro Hero 10 Black

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  • FS1000A and XY-MK-5V - How they work - cheap 433MHz Arduino radio

    The FS1000A transmitter and XY-MK-5V 433Mhz receivers are probably the cheapest options if you want to do any kind of radio transmission with Arduino. And many people assume that it will work in their application no problem.

    The truth is, that it’s not that simple. The way how whose 433MHz radio modules are made puts multiple limitations: They do not add any encoding or packeting. It’s just a pure radio layer. Your Arduino code has to do the coding and decoding of the incoming signal. You can not transfer data too slowly, as the receiver will boost sensitivity and start outputting random noise on its output You can not transfer data too fast, as the signal will be lost

    If you are interested, you can listed about all the details in this video

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Paweł Spychalski

If you have any comments or questions, or just want to say "Hi, Pawel, good job!" you can always drop me a tweet!