DIY 3D printer project

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Frank documented a 3D printer build, called Hephaestus:

I finally did it, I designed and built my own 3D printer. This is in no way “the best 3D printer”. Instead, this was an epic and nightmare project that exercised my ability to engineer and build my own CNC machine. Along the way, I figured out what I did well and what I did badly, mistakes were made and sometimes fixed, even ignored.

You can find the build log on Eleccelerator project page.

RetroZero (retropie handheld)

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Facelesstech published a new build:

I’ve been on a quest for while now trying to build a retropie handheld that was functional but didn’t break the bank. So far I’ve made ZeroBoy – A poor man’s retropie “portable” and a follow-up ZeroBoy rev C – An improved poor mans retropie portable. These were great but I think I have made a much better system with all the features included.

More details  on Facelesstech blog.

Check out the video after the break.

App note: Operating voltage ratings for inductors

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Coilcraft’s app note on why inductor’s voltage ratings are uncommonly mentioned in most applications. Link here (PDF)

Voltage ratings are often specified for many electronic components, including capacitors, resistors and integrated circuits, but traditionally this has been rare for inductors. Recent trends, particularly the introduction of higher voltage rated semiconductor devices, have created a new emphasis on operating voltage as part of the inductor selection process. Inductors once considered optimized for high current, low voltage applications are finding homes in new designs that apply higher voltage stress to the inductor.

App note: Power supply topologies – Forward of Flyback? Which is Better? Both!

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App note from Coilcraft camparing two recognized power supply topologies. Link here (PDF)

Beatles or Stones? Michael or LeBron? Deep dish or thin crust? Forward or flyback? These are just a few of the age-old questions that have been hotly debated over the years, people arguing their opinions with great vigor. But, the truth is, most of the time the answer is both, due to the merits of each.

In this article, we will focus on forward or flyback. We’ll discuss the characteristics of active clamp forward and continuous conduction flyback isolated power supply topologies and demonstrate the design and performance trade-offs of each using two telecom-oriented power supplies as examples.

HX711 load cell amplifier library for AVR ATmega

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A HX711 load cell library for AVR ATmega:

HX711 is a precision 24bit ADC IC designed for weigh scales and industrial control applications to interface directly with a bridge sensor.
A load cell is a transducer that is used to create an electrical signal whose magnitude is directly proportional to the force being measured.
The library you can find here is usefull to implement a weigh scale using the HX711.

More details on Davide Gironi’s blog.

Check out the video after the break.

Qi wireless power receiver from scratch

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Vinod made a Qi wireless power receiver using Attiny13, that is available on GitHub:

I have only two aims while trying this. The receiver should get powered by the transmitter continuously. I should be able to control the power received by adjusting the error packets, in my case I am trying to keep received voltage always 10v.
There are lot more but I am only interested in this two features for now, so I will not be following the complete Qi specs described on the WPC documents, by the way, it worked for me without any issue. This is purely experimental.

See the full post on his blog.

Check out the video after the break.

Teardown of a Spex HS1000 monochromator controller

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Kerry Wong did a teardown of a SPEX HS1000 monochromator/spectrometer controller:

Monochromator is one of those things that has always fascinated me. Over the years, I have done quite a few experiments (I, II, III) with an EP200Mmd monochromator and it was a lot of fun. Because monochromators are such highly specialized equipment, decent ones are hard to come by at reasonable prices second hand. So my strategy has been to scour eBay once a while and pick up bit and pieces whenever I can.

See the full post on his blog.

Check out the video after the break.

App note: Replacing traditional optocouplers with Si87xx digital isolators

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Digital isolator from Silicon Labs app note shows pin compatible plus high performance replacment of incumbent optoisolators, link here (PDF)

Opto-couplers are a decades-old technology widely used for signal isolation, typically providing safety isolation, signal level shifting, and ground loop mitigation. They are commonly used in a wide range of end applications, including data communication circuits, switch mode power systems, measurement and test systems, and isolated data acquisition systems. Optocouplers have several weaknesses, including parametric instability with temperature and device aging, significant internal parasitic couplings, long propagation delay times, narrow operating temperature ranges, and relatively low reliability.

Today’s advanced CMOS signal isolation products offer better timing performance, higher reliability, and lower power consumption compared to optocouplers and are capturing sockets traditionally held by optocouplers. However, converting to CMOS isolation devices has, most often, required circuit changes and PCB modifications that cost money and create design risks, until now.

App note: Introduction to gapped clocks and PLLs

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App note from Silicon Labs on the introduction of gapped clocks, how they can be used in network timing, and their impact upon phase locked loop (PLL) technology. Link here (PDF)

Gapped clocks are periodic clock signals of a single clock frequency that have clock pulses removed from their stream. Well-formed gapped clocks do not have reduced width pulses (known as runt pulses). Rather, each individual clock pulse is either completely present or completely absent.