Rohde & Schwarz FSIQ 7 Logic Analyzer's RF module, back side. (Source: Roberto Barrios)

Rohde & Schwarz FSIQ Signal Analyzer IF-Filter Module Repair

January 12, 2022 by Maya Posch 9 Comments

Who can’t resist snapping up a piece of really expensive laboratory testing gear for next to nothing when browsing eBay or similar? Maybe it’s giving you mournful eyes when browsing through a yard sale. Often such gear is sold for cheap because it’s defective, but with a bit of attention, can be brought back to life. This is how [Roberto Barrios] ended up with a Rohde & Schwarz FSIQ 7 signal analyzer lounging around his place for a few months until he got it fixed.

Part of the fix was replacing a busted RF converter module (A160 IF-Filter) with a used-but-working replacement, but this left the device with odd calibration failures. In the process of tracing down the cause, [Roberto] took many high-resolution images of both sides of the PCBs in order to reverse-engineer the circuit. To complicate matters, the calibration results indicated that the unit’s filters were fine on boot-up, but would deviate after a few minutes.

After extending the filter module to work outside the enclosure and experimental use of a hot air gun, ultimately the cause was tracked down to an unsoldered pad. Considering the extremely simple cause of the failure, it would seem that R&S QA had an off-day when that replacement module was produced. If there’s a lesson to be learned here it is probably that a simple visual inspection is sometimes all that is needed to fix a hardware issue.

What are your expensive gear repair stories? What did you learn that could save others hours of their time?

Regenerative Medicine: The Promise Of Undoing The Ravages Of Time

January 12, 2022 by Maya Posch 15 Comments

In many ways, the human body is like any other machine in that it requires constant refueling and maintenance to keep functioning. Much of this happens without our intervention beyond us selecting what to eat that day. There are however times when due to an accident, physical illness or aging the automatic repair mechanisms of our body become overwhelmed, fail to do their task correctly, or outright fall short in repairing damage.

Most of us know that lizards can regrow tails, some starfish regenerate into as many new starfish as the pieces which they were chopped into, and axolotl can regenerate limbs and even parts of their brain. Yet humans too have an amazing regenerating ability, although for us it is mostly contained within the liver, which can regenerate even when three-quarters are removed.

In the field of regenerative medicine, the goal is to either induce regeneration in damaged tissues, or to replace damaged organs and tissues with externally grown ones, using the patient’s own genetic material. This could offer us a future in which replacement organs are always available at demand, and many types of injuries are no longer permanent, including paralysis. Continue reading “Regenerative Medicine: The Promise Of Undoing The Ravages Of Time” →

Open 3D Engine editor with Amazon Shader Language file and asset from the game Deadhaus Sonata open. (Credit: O3DE project)

Open 3D Engine: Amazon’s Old Clothes Or A Game Engine To Truly Get Excited About?

January 10, 2022 by Maya Posch 14 Comments

Recently Amazon announced that they would be open sourcing the 3D engine and related behind their Amazon Lumberyard game tooling effort. As Lumberyard is based on CryEngine 3.8 (~2015 vintage), this raises the question of whether this new open source engine – creatively named Open 3D Engine (O3DE) – is an open source version of a CryTek engine, and what this brings to those of us who like to tinker with 2D, 3D games and similar.

When reading through the marketing materials, one might be forgiven for thinking that O3DE is the best thing since sliced 3D bread, and is Amazon’s benevolent gift to the unwashed masses to free them from the chains imposed on them by proprietary engines like Unity and Unreal Engine. A closer look reveals however that O3DE is Lumberyard, but with many parts of Lumberyard replaced, including the renderer still in the process of being rewritten from the old CryEngine code.

What Makes a Good Game Engine?

My own game development attempts started with the Half Life engine and the Valve Hammer editor, as well as the Doom map editor. This meant that some expectations were set before encountering today’s game engines and their tools. The development experience with the Hammer editor in the late 1990s was pretty much WYSIWYG, and when I was just getting started with Unreal Engine 4 (UE4) a number of years back this was pretty much the same experience, making it relatively easy to hit the ground running. Continue reading “Open 3D Engine: Amazon’s Old Clothes Or A Game Engine To Truly Get Excited About?” →

Painted Over But Not Forgotten: Restoring Lost Paintings With Radiation And Mathematics

January 4, 2022 by Maya Posch 23 Comments

An intrinsic property of paintings, that makes them both wonderful and very annoying, is the fact that they are physical objects. Sometimes they survive across the ages as amazing artifacts of their era, but they are also susceptible to being lost and even destroyed. Sometimes this destruction is deliberate, such as when a painting is painted over.

Artists reuse canvas all the time — painting over what was already there. Sometimes they might be coerced by a client into altering a painting, or removing entire elements from a scene. Fortunately, nowadays we have many techniques, involving x-rays and infrared radiation, that can analyze paintings to determine not only the composition of what we can see with the naked eye, but also that what lies underneath.

In some cases, we can then reconstruct what was previously hidden, returning to physical reality paintings and sketches which haven’t seen the light of day for sometimes centuries. Continue reading “Painted Over But Not Forgotten: Restoring Lost Paintings With Radiation And Mathematics” →

The Benefits Of Critiquing Your Own PCB Designs

January 3, 2022 by Maya Posch 8 Comments

In a recent retrospective video, [Phil] from Phil’s Lab goes through a number of his early PCB designs, to critique and comment on what he likes and doesn’t like in these designs. Even though it’s only been a few a few years, he founds plenty that’s wrong. From poor and inconsistent formatting in the schematic, to sloppy and outright broken PCB layouts. It’s a fascinating look at years of lessons learned.

[Phil] comments on the importance of clear labeling and organization of sections and pages in the schematic to make it obvious what the function of a block is. Other lessons include the labeling of nets to make PCB routing a lot easier, making good use of PCB planes, getting all relevant information on components and layout in the schematic as a comment, and connecting decoupling capacitors to their relevant pins.

Although we tend to forget about older projects, it can be very interesting to take a look at them now and then, to see (hopefully) our progress over the years. In the case of [Phil] it’s fascinating to see the transition from a basic two-sided board with THT components to multi-layer boards with STM32 MCUs.

Continue reading “The Benefits Of Critiquing Your Own PCB Designs” →

Keeping The Philippines’ Surface Waters Clean With Kabooms

January 2, 2022 by Maya Posch 34 Comments

[Rich] over at Tropical Ocean Cleanup on YouTube has been working hard to prevent plastic waste from getting into the waters around the Philippines. Even as a mostly one-man crew, he’s collecting large sums of plastic waste using a boom system which he fittingly made out of waste: old tires and empty plastic bottles. This Kaboom system is a low-cost method of capturing any waste so that it can be collected and properly disposed of. In addition [Rich] also installs containers where locals can dispose of their plastic trash.

The Kaboom system is detailed by [Rich] in this video (also linked after the break). As a shoestring budget project, it relies heavily on donations and local support to install more of these booms. It is however a highly effective way to prevent such common plastic waste from making it into the oceans in the first place. Having these booms made out of waste items that are commonly found where humans roam should make this a snap.

Ideally, local governments would be installing such capturing systems and easy waste disposal options, but sometimes it seems grassroots efforts like these are what will bring the fastest change.

Curious about what to do with all that plastic waste once you collect and identify it? How about making some plastic bricks?

Continue reading “Keeping The Philippines’ Surface Waters Clean With Kabooms” →

Realtime Shadows On N64 Hardware

December 26, 2021 by Maya Posch 22 Comments

Although the Nintendo 64 console has in the minds of many been relegated to the era of ‘firmly obsolete graphics’, since its graphic processor’s (GPU’s) lineage traces directly to the best which SGI had to offer in the 1990s, it too supports a range of modern features, including dynamic shadows. In a simple demo, [lambertjamesd] demonstrates how this feature is used.

As can be seen in the demonstration video (linked after the break), this demo features a single dynamic light, which casts a shadow below the central object in the scene, with a monkey object floating around that casts its own shadow (rendered into an auxiliary frame buffer). This auxiliary buffer is then blended into the main buffer, as explained by [ItzWarty] over at /r/programming on Reddit.

This effectively means that the main scene uses a shadow volume, which was used extensively with Doom 3. The primary reasons for why the N64 didn’t use shadow volumes all over the place was due to the limitations this places on the shadow caster (objects) in the scene, such as the need to be convex, and overlap is likely to lead to artifacts and glitches.

Doom 3 would fix this with the use of a stencil buffer that would further refine the basic dynamic lighting support on the N64, which ultimately would lead to the fancy video game graphics we have today. And which no doubt will look properly obsolete in another decade again, as usual.

Continue reading “Realtime Shadows On N64 Hardware” →