Testing the range of NRF24L01+ modules

One of the biggest trends these days is making everything wireless. And sometimes it really comes in handy to have a radio module capable of transmitting data between two microcontrollers. And because I don’t know that much about radios, I have to stick to ready-made modules, like the NRF24L01. While you can get a lot … “Testing the range of NRF24L01+ modules”

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Simple camping light/torch

One of the most useful tools when camping is a flashlight. They come in a ton of different shapes – headlamps, torches, lanterns… I have a good headlight, but sometimes I want to, say, illuminate a whole tent or a room. For this a headlamp is not suitable, because it is very directional. So, from … “Simple camping light/torch”

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Arduino Universal Battery Charging Shield update

One of my most viewed projects ever (both on Instructables and Github) is my AVR Universal Battery Charger. It was also one of the very first projects I ever published, so there wasn’t a proper schematics or board layout (back then I simply didn’t care), my code was messy and the hardware had some flaws. … “Arduino Universal Battery Charging Shield update”

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3D printed charger for Yi 4K camera battery

I own an action camera – the Yi 4K – and I am very satisfied with it. However, even though it has longer battery life than a GoPro, it still runs for only ~90 minutes on a single battery. For this reason, I bought a bunch of replacement batteries from Ebay for just 6 dollars/piece! … “3D printed charger for Yi 4K camera battery”

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An interesting experiment: cooling a Cree LED on a normal FR4 PCB

Modern LEDs have enormous efficiency – up to 40 % – but this still means that if you mount a 5 W LED on a PCB it will generate up to 3.5 W of heat. In one of my recent experiments, I tried making a headlamp using a Cree XPG-BWT LED. I made a small … “An interesting experiment: cooling a Cree LED on a normal FR4 PCB”

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Trace & via current carrying capacity on PCBs from JLCPCB

If you ever designed your own printed circuit board, you might have wondered “how thick does this trace needs to be?” or “how big this via needs to be?”. As always, you can try to Google it – however, you will find a lot of conflicting information, and that is why I ordered a simple … “Trace & via current carrying capacity on PCBs from JLCPCB”

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Multicell Lithium Battery Charging & Balancing circuit

You probably know that charging lithium batteries isn’t particularly easy. But if you have just a single cell, you can get an IC to do this for you – the most popular being probably the TP4056 or the MCP73831 (you can get both of them from Ebay). But if you want to have a battery … “Multicell Lithium Battery Charging & Balancing circuit”

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Lithium Battery Utility Board V1.2

I use lithium batteries a lot. However, they are not the easiest to use – you need a dedicated charging IC, complicated protection circuitry, boost module to power 5 V circuitry, switches, connectors… So I designed a board with all of these features. This is hopefully the last and final revision of my Lithium Battery … “Lithium Battery Utility Board V1.2”

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An abandoned project: the STM32 watch

A few months ago, my watch broke. Instead of buying a new one, I decided to try to build a watch myself. Since I am not a mechanical engineer, I had to use electronics – 60 LEDs to emulate a classical watch face and some microcontroller to drive them. I was more interested in how … “An abandoned project: the STM32 watch”

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