Experiments in implementing the WS2812B protocol in AVR MCUs without bit-banging

I started to experiment with the WS2812 LED, more specifically the WS2812B, which is a better revision in term of connections. These are the very famous individually addressable RGB LED, where tons of sources are available. Mainly due to their low cost, they are spread to the maker scene like a rhinovirus in a primary … Leggi tutto Experiments in implementing the WS2812B protocol in AVR MCUs without bit-banging

AOC I2475PXQU LCD monitor – teardown and repair

One of few repairs that went smooth and succesful. Using a monitor with integrated USB hub can be useful, but also tricky, if such hubs are designed in a cheap way or is not fool proof, and I am a fool. If that is the case, overloading the output lead to a dead port. And … Leggi tutto AOC I2475PXQU LCD monitor – teardown and repair

Switching converters nostalgia: a brief history

I have some kind of interest in electronic projects, whether hobbists or a professional ones, which are based on standard and always available sub-components. Those always available parts are also called jelly bean components, like resistors, capacitors and cheap basic parts, like op amps (including in my opinion also LM741, LM324, even TL081 and the … Leggi tutto Switching converters nostalgia: a brief history

Dimming LEDs (part 2/3) – Sneaky non-linear events while using the PWM technique

In the previous article we tried to analyze what is the Contrast Ratio in a LED driver and how the non-idealities are giving a boundary on the minimum allowable PWM period. That was quite worth a full article, but a big part was indeed missing. Here we will go through how the PWM period and … Leggi tutto Dimming LEDs (part 2/3) – Sneaky non-linear events while using the PWM technique

Dimming LEDs (part 1/3) – Analog and digital, not analog vs. digital

While messing around with dimmable DC-DC converters for LED drivers, I had the need to quantify the contrast ratio of a dimmable light. Turns out it is not that trivial, specially when combining switching periods, transients and mixed analog/PWM dimming. Looking for contrast ratio on the internet is only useful if you want to buy a TV, not if you want to build a LED driver. Also, on the web not all information seems to be correct, therefore this article and its possible continuation is the result of long investigations and discussions between engineers.