Probably The Largest Selfie Camera In The World

November 16, 2023 by No comments

Most readers will have some idea of how a camera works, with a lens placed in front of a piece of film or an electronic sensor, and the distance between the two adjusted until the images is in focus. The word “camera” is a shortening of “camera obscura”, the Latin for “dark room”, as some early such devices were darkened rooms in which the image was projected onto a rear wall. [David White], a lecturer at Falmouth University in the UK has created a modern-day portable camera obscura using a garden gazebo frame, and uniquely for a camera obscura, it can be used to take selfies.

As might be expected the gazebo frame covered with a dark fabric forms the “room”, and the surface on which the image is formed comes from a projection screen. The lens is a custom-made 790 mm f/5.4, not exactly the type of lens found off-the-shelf. The selfie part comes from a Canon digital camera inside the gazebo focused on the frame, using its Wi-Fi control app a subject can sit at the appropriate point in front of the lens and take the selfie as they see fit.

The resulting images have a pleasing ethereal feel to them, and while it’s definitely not the most practical taker of snaps it’s still very much a camera to be impressed by. We’d be curious to see how it would perform as a pinhole camera, and even though it’s nowhere near the 2006 record pinhole image taken using an abandoned US Marine Corps aircraft hangar we think it would still deliver when given enough light. Meanwhile this isn’t the first time we’ve shown you a camera obscura, here’s one using the back of a U-Haul truck.

Lessons In Mass Production From An Atari Punk Console

November 16, 2023 by 7 Comments

Sometimes the most interesting part of a project isn’t the widget itself, but what it teaches you about the manufacturing process. The story of the manufacturing scale-up of this Atari Punk Console and the lessons learned along the way is a perfect example of this.

Now, don’t get us wrong — we love Atari Punk Consoles. Anything with a couple of 555s that bleeps and bloops is OK in our books. But as [Adam Gulyas] tells the tale, the point of this project was less about the circuit than about the process of making a small batch of something. The APC was low-hanging fruit in that regard, and after a quick round of breadboarding to decide on component values, it was off to production. [Adam] was shooting for 20 units, each in a nice enclosure and a classy package. PCB assemblies were ordered, as were off-the-shelf plastic enclosures, which ended up needing a lot of tweaking. [Adam] designed custom labels for the cases, itself a fraught job; glossy label stock and button bezels apparently don’t mix.

After slogging through the assembly process, boxing the units for shipping was the next job. [Adam] sourced jewelry boxes just a bit bigger than the finished APCs, and rather than settle for tissue paper or packing peanuts, designed an insert to hold the units snugly. That involved a lot of trial and error and a little bit of origami-fu, and the results are pretty nice. His cost per unit came out to just a hair over $20 Canadian, including the packaging, which is actually pretty remarkable for such a short production run.

[Adam] includes a list of improvements for larger-scale runs, including ordering assembled PCBs, outsourcing the printing processes, and getting custom boxes made so no insert is needed. Any way you cut it, this production run came out great and teaches us all some important lessons.

Robots: How The Pros Keep Them Safe

November 15, 2023 by 4 Comments

Robotic safety standards are designed for commercial bots, but amateur robot builders should also consider ideas like the keepout zone where a mobile robot isn’t permitted to go or how to draw out the safety perimeter space for your experimental robot arm. After all, that robot arm won’t stop crushing your fingers because you built it yourself. So, it is worth looking at the standards for industrial robots, even if your aim is fun rather than profit.

The basics of this for fixed robots like robot arms are defined in the standard R15-06. You don’t need to read the full text (because it costs $325 and is *incredibly* tedious to read), but the Association for Advancing Automation has a good background on the details. The bottom line is to ensure that a user can’t reach into an area that the robot arm might move to and provide a quick and easy way to disable the motors if someone does reach in.

Robots that move, called Industrial Mobile Robots (IMRs) or Autonomous Mobile Robots (AMRs) bring in a whole new set of problems, though, because they are designed to move around under their own control and often share space with humans. For them, the standard is called R15.08. The AGV network has a good guide to the details, but again, it boils down to two things: make sure the robot is keeping an eye on its surroundings and that it can stop quickly enough to avoid injury.

The Linux Scheduler And How It Handles More Cores

November 15, 2023 by 18 Comments

Sometimes you read an article headline and you find yourself re-reading it a few times before diving into the article. This was definitely the case for a recent blog post by [The HFT Guy], where the claim was made that the Linux kernel has for fifteen years now been hardlocked into not scheduling for more than 8 cores. Obviously this caused a lot of double-checking and context discovery on both Hacker News and the Level 1 Techs forum. So what is going on exactly? Did the Linux developers make an egregious error more than a decade ago that has crippled Linux performance to this day? Continue reading “The Linux Scheduler And How It Handles More Cores” →

XMems Cowell MEMS-based tweeter on top of dynamic driver. (Credit: xMEMS)

After MEMS Microphones, MEMS Speakers Enter The Market

November 15, 2023 by 15 Comments

These days it’s hard to not come across solid-state (micro-electromechanical systems, MEMS) microphones, as they are now displacing electret microphones almost everywhere due to their small size and low cost. Although MEMS speakers are not impossible, creating a miniature speaker that can both displace a lot of air (‘volume’) and accurately reproduce a wide range of frequencies – unlike simple piezo buzzers – is a lot tougher. Here a startup called xMEMS figures that they have at least partially cracked the code with their piezoMEMS speakers, with Creative using the Cowell version in their brand-new Aurvana Ace in-ear monitors. Continue reading “After MEMS Microphones, MEMS Speakers Enter The Market” →

Backyard UFO Is Out Of This World

November 15, 2023 by 11 Comments

Halloween may be over for another year, but UFOs in your yard are cool year-round. This one might take the cake. [frydom.john]’s excellent UFO is fully programmable and contains about 2000 addressable RGB LEDs, smoke, a laser-lit ramp, and of course, an alien crew.

Under the hood of the wooden frame, you’ll find a Teensy 4.1 running the blinkenlights. There’s also a hacked smoke machine, because what’s a UFO without smoke or fog emanating from underneath? There are six PC fans to blow it around and recycle it, and the ramp runs on a linear actuator.

[frydom.john]’s project notes (PDF), which they refer to as ‘scrappy/hacky’ are also available. We beg to differ a bit on the scrappy/hacky part; it’s 60 pages long and full of photos and diagrams and charts. Even so, it may not be enough for you to replicate this extraterrestrial vehicle, so [frydom.john] is open to questions. Be sure to check this thing out after the break.

Want to have your UFO lift off of the ground? It’s possible with the Coandă effect.

Continue reading “Backyard UFO Is Out Of This World” →

Don’t Look Up, Or You’ll See The Time From This VFD Projection Clock

November 15, 2023 by 19 Comments

Ceiling clocks were a bit of a thing back in the days when clock radios were a fixture of nightstands. The idea was to project the time onto the ceiling so you’d only have to roll over onto your back and open your eyes to check the time, instead of potentially disturbing your slumber by craning your neck around to see the front of the clock.

As we recall, what sounded like a good idea was iffy in practice, with low-end optics and either weak incandescent bulbs or blazing LEDs. This nifty VFD projection clock by [Thomas Shupfs] seeks to fix those problems, and from the look of it does a pretty good job. It takes advantage of something else that fell out of favor with consumers — analog photography — by tapping into the ready supply of unwanted lenses. He paired that up with an IVL2-7/5 vacuum fluorescent display inside a 3D printed case with a cone-shaped extension to hold the lens at the right distance above the display. [Thomas] says that the STM32 software only supports JSON-RPC over USB at this time, and includes a couple of Python programs with examples of how to set the time and check the accuracy of the clock.

[Thomas] compares the clock head-to-head against his old LED projection clock, as seen in the featured image above; we flipped it for a better idea of what it would look like from bed. We’ve got to say the soft blue glow of the VFD would be a lot more pleasant to wake up to than the bright red LED projection. But this soft white projection clock is nice too.

Thanks to [skymab] for the tip.