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3.3 V fix for the black CH341A Mini Programmer without lifting a pin

2020-12-27 11:04
While the CH341A Mini Programmer is a very versatile device - not only can it be used as an SPI flash programmer, but also as a UART and possibly even an AVR programmer, it is known to have a design flaw, probably due to a misinterpretation of the fairly vague CH341A datasheet by the people who have designed the Mini Programmer.
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Computer controlled IR remote control for an RGB LED strip

2017-08-08 18:23
I've got one of these simple remote controlled RGB LED strips. Using the IR remote control that came with it to select colors is fine, but I wanted to be able to control it through a computer. That way it would be possible to do things like turning it off when playing a movie for instance, or using it to signal any kind of event.


There are different options on how to achieve that. I could have replaced the whole LED controller circuitry with my own, but I didn't want to do that. What I decided to do instead is create a small circuit that emits IR signals that the original controller understands. That way I can still use the original remote control and do not have to modify any of the original LED strip components. The downside to this is that I am stuck with the capabilities of the original controller, which are rather limited.
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Coreboot on the Lenovo Thinkpad X220

2016-12-30 11:00
I have finally come around to install Coreboot on my X220 laptop. It is an X220 with a Core i5-2520M and 16 GB of DDR3-1600 RAM.

Coreboot is an open source replacement for the BIOS/UEFI firmware of a variety of laptops and mainboards. Coreboot needs to be combined with a payload component, since Coreboot itself doesn't do a whole lot besides hardware initialization. The payload I am using here is SeaBIOS, which implements the features of a PC BIOS.

SeaBIOS payload

It allows you to boot most PC operating systems, including those that rely on the classic PC BIOS features. For UEFI support there is the TianoCore payload. It is also possible to use the GRUB bootloader as a payload or embed a Linux kernel as a payload (if the flash chip is large enough).
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Schematic for the C64 power supply project

2016-04-06 16:13
I have been asked for a schematic of my C64 power supply a couple of times. So here it is.

C64 power supply

The correct value for the transformer's primary rating depends on your mains voltage, of course.

For a detailed description of my circuit, please have a look at the original article.

A simple power indicator LED mod or: Why are super-bright blue LEDs so common in consumer electronics?

2012-10-15 17:29
Since the wide availability of blue LEDs, manufacturers of electronics devices tend to use blue LEDs as power indicators. They especially seem to like those extra-bright blue LEDs.


I, on the contrary, find them pretty annoying. Am I alone here? Do people actually like them?
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