AVR-based Li-Ion battery charger

If you ever worked with lithium batteries, you probably know the TP4056 – a chip for charging lithium batteries with CC-CV profile, two LEDs for state-of-charge indication, temperature input and so on. You can find it relatively cheaply on Ebay or similar sites, either as standalone IC or on a small and very practical breakout … “AVR-based Li-Ion battery charger”

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STM32 Open Source multimeter – revision 1.4

I was hoping that this release of my multimeter project will be the final one. However, during testing, I still discovered things that needed changing or modifying, so in this article, I’ll at least describe some of the biggest changes and achievements of this revision & and also what went wrong and forced me to … “STM32 Open Source multimeter – revision 1.4”

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STM32 Open Source multimeter – revision 1.3

Yesterday, parts for revision 1.3 finally arrived and this meant I could start populating the PCB. I managed to populate and test it in just two days (which is unusually fast for me) and in this article I’ll explain all the changes to the multimeter. If you forgot all the features it already has, check … “STM32 Open Source multimeter – revision 1.3”

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STM32 Open Source Multimeter

There is a new version. Read about it here! One of the most essential tools for anybody interested in electrical engineering is certainly a Digital Multi Meter (DMM). The problem is you really never have enough of these – there is always one more voltage or one more current that you need to measure when … “STM32 Open Source Multimeter”

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Seven Segment Multifunction Display

Often, when I am prototyping something on a breadboard or elsewhere, I need to see voltage levels at multiple points of the circuit. Of course you can hook up multiple multimeters, but a) I don’t have that many multimeters and b) they are usually relatively big and take a lot of space on my small … “Seven Segment Multifunction Display”

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ESP8266 ultra low power thermometer

This is another project I originally build for a ground school here in the Czech Republic. But in the end, I liked it a lot, so I build a few of these modules for myself as well. It’s basically a small ESP8266-based board with a BME280/BMP280 sensor and these features: measures temperature, humidity, pressure (BME280) … “ESP8266 ultra low power thermometer”

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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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