Answering Some Pico Balloon Questions

February 24, 2023 by 29 Comments

When the US Air Force shot down some suspected Chinese spy balloons a couple of weeks ago, it was widely reported that one of the targets might have been a much more harmless amateur radio craft. The so-called pico balloon K9YO was a helium-inflated Mylar balloon carrying a tiny solar-powered WSPR beacon, and it abruptly disappeared in the same place and time in which the USAF claimed one of their targets. When we covered  the story it garnered a huge number of comments both for and against the balloonists, so perhaps it’s worth returning with the views of a high-altitude-ballooning expert.

[Dave Akerman] has been sending things aloft for a long time now, we think he may have been one of the first to put a Raspberry Pi aloft back in 2012. In his blog post he attempts to answer the frequently asked questions about pico balloons, their legality, whether they should carry a beacon, and what the difference is between these balloons and the latex “weather balloon” type we’re familiar with. It’s worth a read, because not all of us are part of the high-altitude balloon community and thus it’s good to educate oneself.

Meanwhile, you can read our original report here.

Tiny Machine Learning On As Little As 2 KB Of RAM

February 24, 2023 by 6 Comments

All of the machine language stuff coming out lately doesn’t affect you if you are developing with embedded microcontrollers, right? Perhaps not. Microsoft Research India wants you to use their EdgeML tool to do machine learning tasks such as gesture recognition in tiny devices like an Arduino Uno. According to the developers, you might need as little as 2 KB of RAM. There’s no network connection required and the work is using Tensorflow underneath, so it is compatible with much of what you’ll find for bigger computers.

If you add processing power, you can get more capability. For example, one of the demonstrations is a wake-word recognizer on a Raspberry Pi Zero (although the page for that demo seems to be missing at the moment; try the GesturePod, instead).

The system generally uses Python, but there are efficient C++ implementations for selected algorithms. The code lives on GitHub. There are also a number of research papers about each tool that you can find on the GitHub page. There’s also a recent paper on MinUn, an attempt to make things even more efficient for ARM microcontrollers. In particular, MinUn can store approximate numbers to save space, allows for variable precision of tensors, and tries to reduce memory fragmentation, an important feature for CPUs that don’t have memory management units.

If you haven’t studied TensorFlow yet, start here. Why use something like this with a microcontroller? How about smarter robots?

Sailing On A Sea Of Seven-Segment Displays

February 23, 2023 by 39 Comments

The amount of information the humble seven-segment display can convey is surprising. There are the ten numerals, dead-ringers or reasonable approximations for about half the alphabet, and even a few not-quite-canonical symbols. But when you put 12,288 segments to work, you get all that and much more.

Behold Sea of Segments, an art piece by [Will Gallia] that really pushes what’s possible with seven-segment displays. The piece, which looks about the size of a decent flat-panel TV, is composed of an 8×6 array of PCBs, each of which holds an 8×4 array of white LED seven-segment displays; each board also holds two TLC5920 LED drivers. [Will] designed the PCBs to tile horizontally and vertically, making it possible to take data either from the top or right side and output to the bottom or left. Power is distributed to the modules through a series of steel bus bars, which also provide structural support for the display. The whole thing lives in an enclosure with a smoked acrylic front panel, and hangs from a pair of steel cables that also provide power.

Under the hood, a PocketBeagle does all the heavy lifting of talking to the display and translating images onto the display. [Will] came up with an encoding scheme that gives about five bits of grayscale, and built a program to figure out which segments should be lit to create an image. The result is a smooth and convincing reproduction of videos of waves on a beach, which is where the project gets its name. Check out the results in the video below.

[Will] says he drew inspiration for this build from the DigitGrid by [Skot9000]. That was a great project too, but Sea of Segments takes the concept to another level.

Continue reading “Sailing On A Sea Of Seven-Segment Displays” →

German Air Force Surplus Teardown

February 23, 2023 by 11 Comments

It isn’t clear to us how [mrsylvain59] came into possession of a late-model piece of military gear from the German airforce, but we enjoyed watching the teardown below anyway. According to the documentation, the thing has a huge price tag, although we all know that the military usually pays top dollar for various reasons, so we are guessing the cost of the parts is quite a bit less than the price tag.

We don’t think [mrsylvain59] was sure what the amplifier (verstärker is German for amplifier) does. However, we recognized it as an avionics box from a UH-1 helicopter. We aren’t sure of its exact function, but it is classified under “Automatic Pilot Mechanisms and Airborne Gyro Components.”

Continue reading “German Air Force Surplus Teardown” →

Two people lounge over a wooden tabletop to lean on a large black laptop. It has a green leaf on its 43" LCD desktop and RGB lighting around its edge is glowing a slightly deeper shade of green.

Supersized Laptop Laughs In The Face Of Portability

February 23, 2023 by 18 Comments

Sometimes a project needs to go big, and [Evan and Katelyn] threw portability to the wind to build the “world’s biggest” laptop.

Stretching the believability of “bigger is better,” this laptop features a 43″ screen, an enormous un-ergonomic keyboard, and a trackpad that might be bigger than your hand. Not to be outdone by other gaming laptops, it also features RGB lighting and a logo that really pops with neon resin.

The pair started the build with an aluminum extrusion frame joined by hinges. Plywood forms the top lid and bottom of the device, and the interior was covered with a mix of vinyl and ABS to keep everything tidy. A nice detail is the windows cut in the area above the keyboard to keep an eye on the charge of the two battery packs powering the laptop. Weighing more than 100 pounds, we suspect that this won’t be the next revolution in computing.

If you need more supersized gadgets, maybe try out the world’s biggest working keyboard or this giant Xbox Series X?

Fixing A Reflow Oven’s Conveyer Belt With An NE555 And Stepper Motors

February 23, 2023 by 10 Comments

Some design choices on manufacturing equipment really leave you scratching your head for a while, as recently happened to [Chris Cecil] when the belt on a reflow oven’s conveyer snapped. Although the solution seems simple enough, getting a new belt on the thing would involve essentially taking the entire machine apart, before reassembling it again. Thus the frayed belt went through the oven over and over until during a recent production run of Smoothieboard controller boards until [Chris] heard a funny noise and the conveyer ground to a halt.

Moving the conveyer by hand kind of worked, but with a more permanent fix urgently needed to finish the production run, two stepper motors took the place of the belt, which just left driving these steppers to keep the conveyer moving in sync. Lacking a simple Arduino board to toss at it, and with a Smoothieboard being absolute overkill, [Chris] figured that a humble NE555 timer IC ought to do the job just as well.

Using a project on Hackaday.io by [KushagraK7] as the starting point, and a 1992-vintage NE555 IC harvested from an old project, [Chris] managed to put together a basic stepper driver that uses the NE555 to provide the timing signal. In addition to restoring basic functionality like starting and stopping the conveyer belt, [Chris] added a new feature with the reversing of the conveyer direction. Along with some cobbled together components to physically rotate the conveyer’s two rollers, it restored the reflow oven to working condition.

And one day the prototyped driver board will be updated to a proper PCB. It’s only temporary, after all :)

Continue reading “Fixing A Reflow Oven’s Conveyer Belt With An NE555 And Stepper Motors” →

Sneaky Clock Displays Wrong Time If It Catches You Looking

February 23, 2023 by 20 Comments

We have a soft spot for devices that subvert purpose and expectation, and that definitely sums up [Guy Dupont]’s Clock That Is Wrong. It knows the correct time, but whether or not it displays the correct time is another story. That’s because nestled just above the 7-segment display is a person sensor module, and when it detects that a person is looking towards it, the clock will display an incorrect time, therefore self-defeating both the purpose and primary use case of a clock in one stroke.

The person sensor is a tiny board with tiny camera that constantly does its best to determine whether a person is in view, and whether they are looking towards the sensor. It’s a good fit for a project like this, and it means that one can look at the clock from an oblique angle (meaning one is out of view of the sensor) and see the correct time. But once one moves in front of it, the time changes. You can watch a brief video of it in action in this Twitter thread.

One interesting bit is that [Guy] uses an ESP32-based board to drive everything, but had some reservations about making a clock without an RTC. However, he found that simply syncing time over the network every 10 minutes or so using the board’s built-in WiFi was perfectly serviceable, at least for a device like this.

This reminds us a little of other clocks with subtly subversive elements, like the Vetinari Clock which keeps overall accurate time despite irregularly drifting in and out of sync. Intrigued by such ideas? You’re not alone, because there are even DIY hobby options for non-standard clock movements. Adding the ability to detect when someone is looking directly at such a device opens up possibilities, so keep it in mind if it’s time for a weekend project.