RS485 is a communication standard that should be part of the advanced hardware hacker’s arsenal; it’s not commonly encountered, but powerful exactly when you need it. It’s a physical layer interface for wired communications that uses a single differential pair for noise immunity, has good long-distance properties, and allows many connections to a single bus. Because of that, you will encounter it in security systems and even cameras, wired sensor networks, DMX512 lighting and all sorts of industrial electronics. For our hobbyist goals, you can absolutely use RS485 to build your home (or room) automation system, or a relatively large robot – without all those worries that wireless brings.
The name might remind you of RS232, and that’s because both RS232 and RS485 are standards that come from EIA (Electronics Industries Alliance). It also might remind you of RS422, if you’ve ever seen this name mentioned online – RS422 and RS485 are closely intertwined, sharing most of the physical layer, and I’ll show how exactly they relate. Continue reading “Hacker Dictionary: RS-485 Will Go The Distance”→
As a standard feature of the Linux kernel, device tree overlays (DTOs) allow for easy enabling and configuration of features and drivers, such as those contained within the standard firmware of a Raspberry Pi system. Using these DTOs it’s trivial to set up features like as a soft power-off button, triggering an external power supply and enable drivers for everything from an external real-time clock (RTC) to various displays, sensors and audio devices, all without modifying the operating system or using custom scripts.
It’s also possible to add your own DTOs to create a custom overlay that combines multiple DTO commands into a single one, or create a custom device tree binary (DTB) for the target hardware. Essentially this DTB is loaded by the Linux kernel on boot to let it know which devices are connected and their configuration settings, very similar to what the BIOS component with x86-based architectures handles automatically.
Ultimately, the DTB concept and the use of overlays allow for easy configuration of such optional devices and GPIO pin settings, especially when made configurable through a simple text file as on the Raspberry Pi SBC platform.
As the world begins to slowly pull itself out of the economic effects of the pandemic, there’s one story that has been on our minds for the past couple of years, and it’s probably on yours too. The chip shortage born during those first months of the pandemic has remained with us despite the best efforts of the industry. Last year, pundits were predicting a return to normality in 2022, but will unexpected threats to production such as the war in Ukraine keep us chasing supplies? It’s time to delve into the root of the issue and get to the bottom of it for a Hackaday report.
The Chips Are Down
Consumers were more interested in toilet paper than chip supply during the lockdown.
Going back to 2020, and as global economies abruptly slowed down in the face of stringent lockdowns it’s clear that both chipmakers and their customers hugely underestimated the effect that the pandemic would have on global demand for chips.
As production capacity was reduced or turned to other products in response to the changed conditions, it was soon obvious that the customers’ hunger for chips had not abated, resulting in a shortfall between supply and demand.
We’ve all experienced the chaos that ensued as the supply of popular varieties dried up almost overnight, and as fresh pandemic waves have broken around the world along with a crop of climate and geopolitical uncertainties it’s left many wondering whether the chip situation will ever be the same again.
Green Shoots In Idaho
Idaho leads the way in a chip shortage recovery! inkknife_2000, CC BY-SA 2.0
Amidst all that gloom, there are some encouraging green shoots to be seen. While it’s perhaps not quite time to celebrate, there’s a possibility for some cautious optimism. This month brought the hope that Potato Semiconductor might be cutting the sod on a new production capacity for their ultra-fast digital logic in Idaho, and with other manufacturers following suit it could be that we’ll once again have all the chip capacity we can eat.
But the other side of the chip business coin lies with the customer: we all see the chip shortage from our own semi-insider perspective, but have the tastes of the general public returned towards chips? Early signs are that as consumer confidence returns there are encouraging trends in chip consumption taking root, so we’d be inclined to advise our readers to have cautious optimism. If all goes well, you’ll be having your chips by summer.
The prospects for a new dawn in chip production capacity in 2022 look rosy, but there’s a further snag on the horizon courtesy of the Russian invasion of Ukraine. Like so many industries in a globalised economy, the chip industry depends heavily on supplies, consumables, and machinery from beyond the borders of wherever the plants themselves may lie.
In the case of Ukraine there’s a particular raw material whose supply has been severely interrupted, and though we hope for a speedy resolution of the conflict and a consequent resumption of production, the knock-on effect on the production of chips in the rest of the world can not be underestimated. Despite the ramp-up in output led by Idaho, the production of chips globally still relies heavily on Ukrainian sunflower oil. There’s a possibility that an acceptable substitute might be found in canola oil, but it will remain to be seen whether the chip-eating consumers will notice the taste difference.
We are always impressed with something so simple can actually be so complex. For example, what would you think goes into an analog computer? Of course, a “real” analog computer has opamps that can do logarithms, square roots, multiply, and divide. But would it surprise you that you can make an analog device like a slide rule using a Wheatstone bridge — essentially two voltage dividers. You don’t even need any active devices at all. It is an old idea and one that used to show up in electronic magazines now and again. I’ll show you how they work and simulate the device so you don’t have to build it unless you just want to.
A voltage divider is one of the easiest circuits in the world to analyze. Consider two resistors Ra and Rb in series. Voltage comes in at the top of Ra and the bottom of Rb is grounded. The node connecting Ra and Rb — let’s call it Z — is what we’ll consider the output.
Let’s say we have a 10 V battery feeding A and a perfect voltmeter that doesn’t load the circuit connected to Z. By Kirchoff’s current law we know the current through Ra and Rb must be the same. After all, there’s nowhere else for it to go. We also know the voltage drop across Ra plus the voltage drop across Rb must equal to 10 V. Kirchoff, conservation of energy, whatever you want to call it. Let’s call these quantities I, Va, and Vb. Continue reading “Circuit VR: The Wheatstone Bridge Analog Computer”→
Back in the day, just about everything that used a battery had a hatch or a hutch that you could open to pull it out and replace it if need be. Whether it was a radio, a cordless phone, or a cellphone, it was a cinch to swap out a battery.
These days, many devices hide their batteries, deep beneath tamper-proof stickers and warnings that state there are “no user serviceable components inside.” The EU wants to change all that, though, and has voted to mandate that everything from cellphones to e-bikes must have easily replaceable batteries, with the legislation coming into effect as soon as 2024.
What is a photograph? Technically and literally speaking, it’s a drawing (graph) of light (photo). Sentimentally speaking, it’s a moment in time, captured for all eternity, or until the medium itself rots away. Originally, these light-drawings were recorded on film that had to be developed with a chemical process, but are nowadays often captured by a digital image sensor and available for instant admiration. Anyone can take a photograph, but producing a good one requires some skill — knowing how to use the light and the camera in concert to capture an image.
Eye-Dynamic Range
The point of a camera is to preserve what the human eye sees in a single moment in space-time. This is difficult because eyes have what is described as high dynamic range. Our eyes can process many exposure levels in real time, which is why we can look at a bright sky and pick out details in the white fluffy clouds. But a camera lens can only deal with one exposure level at a time.
In the past, photographers would create high dynamic range images by taking multiple exposures of the same scene and stitching them together.Done just right, each element in the image looks as does in your mind’s eye. Done wrong, it robs the image of contrast and you end up with a murky surreal soup.
It’s often said that the wheels of government turn slowly, and perhaps nowhere is this on better display than at NASA. While it seems like every week we hear about another commercial space launch or venture, projects helmed by the national space agency are often mired by budget cuts and indecisiveness from above. It takes a lot of political will to earmark tens or even hundreds of billions of dollars on a project that could take decades to complete, and not every occupant of the White House has been willing to stake their reputation on such bold ambitions.
In 2019, when Vice President Mike Pence told a cheering crowd at the U.S. Space & Rocket Center that the White House was officially tasking NASA with returning American astronauts to the surface of the Moon by 2024, everyone knew it was an ambitious timeline. But not one without precedent. The speech was a not-so-subtle allusion to President Kennedy’s famous 1962 declaration at Rice University that America would safely land a man on the Moon before the end of the decade, a challenge NASA was able to meet with fewer than six months to spare.
Unfortunately, a rousing speech will only get you so far. Without a significant boost to the agency’s budget, progress on the new Artemis lunar program was limited. To further complicate matters, less than a year after Pence took the stage in Huntsville, there was a new President in the White House. While there was initially some concern that the Biden administration would axe the Artemis program as part of a general “house cleaning”, it was allowed to continue under newly installed NASA Administrator Bill Nelson. The original 2024 deadline, at this point all but unattainable due to delays stemming from the COVID-19 pandemic, has quietly been abandoned.
So where are we now? Is NASA in 2022 any closer to returning humanity to the Moon than they were in 2020 or even 2010? While it might not seem like it from an outsider’s perspective, a close look at some of the recent Artemis program milestones and developments show that the agency is at least moving in the right direction.
