PineTime Smartwatch And Good Code Play Bad Apple

October 16, 2021 by Brian McEvoy 11 Comments

PineTime is the open smartwatch from our friends at Pine64. [TT-392] wanted to prove the hardware can play a full-motion music video, and they are correct, to a point. When you watch the video below, you should notice the monochromatic animation maintaining a healthy framerate, and there lies all the hard work. Without any modifications, video would top out at approximately eight frames per second.

To convert an MP4, you need to break it down into images, which will strip out the sound. Next, you load them into the Linux-only video processor, which looks for clusters of pixels that need changing and ignores the static ones. Relevant pixel selection takes some of the load off the data running to the display and boosts the fps since you don’t waste time reminding it that a block of black pixels should stay the way they are. Lastly, the process will compress everything to fit it into the watch’s onboard memory. Even though it is a few minutes of black and white pictures, compiling can take a couple of hours.

You will need access to the watch’s innards, so hopefully, you have the developer kit or don’t mind cracking the seal. Who are we kidding, you aren’t here for intact warranties. The video resides in the flash chip and you have to transfer blocks one at a time. Bad Apple needs fourteen, so you may want to practice on a shorter video. Lastly, the core memory needs some updating to play correctly. Now you can sit back and…watch.

Pine64 had a rough start with the single-board computers, but they’re earning our trust with things like soldering irons and Google-less Linux mobile phones.

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Where You Are Influences What You Invent

October 16, 2021 by Elliot Williams 21 Comments

[Timon] just bought a new PCB holder setup for his desk. It’s one of those spring-loaded jobbies that uses strong magnets to hold it up off of a work surface, and is made of metal so that you can reflow solder with it. It might be a clone of the PCBite, but frankly I’ve seen similar projects everywhere — it’s hard to say who is copying whom these days. And anyway, that’s not the point.

What struck me about the holders was their tops: they’re repurposed 3D printer nozzles. That’s a fantastic idea because they’re non-magnetic, heat tolerant, relatively uniform, and probably dirt cheap in Shenzhen, where the designer of this board almost certainly lives. Maybe he or she even works in a 3D printer factory? Who knows? But the designer almost certainly looked around for something that would fit the bill, and found the nozzles.

Indeed, there’s been a lot of innovation in all things board-holding coming out of China over the last decade. I can remember when the state of the art was a vise-like affair. (I still like my homebrew Stickvise clone for low, square jobs.)

But with cell phone repairs requiring the ability to hold and reflow ever stranger board shapes, there’s been a flourishing of repositionable holders. The pawn-pillar designs are cool, but their utility rests firmly in how strong the magnets are. (I wouldn’t buy the one linked, for instance, without trying it first-hand.) I really like the look of these jobbies, which have springs to maintain tension. (Will the 3D-printed plastic jaws hold up to multiple reflows?) Anyway, it’s no coincidence that the inventors of these devices are in the cellphone-repair capital of the universe.

The old saying is that necessity is the mother of invention. But what if, like with real estate, it’s location, location, location? You dream up solutions to problems around you, using parts that you’ve got on-hand. If that sounds a little fatalistic, consider that you can also change your surroundings, either physical or even virtual. Are you in the middle of the right challenges and opportunities?

Unique Seven-Segment Display Relies On FR-4 Fluorescence

October 16, 2021 by Dan Maloney 11 Comments

It’s interesting what you see when you train a black light on everyday objects. We strongly suggest not doing this in a hotel room, but if you shine UV light on, say, a printed circuit board, you might see what [Sam Ettinger] did, which led him to build these cool low-profile seven-segment fluorescent PCB displays.

As it turns out, at least some FR-4 PCBs fluoresce under UV light, giving off a ghostly blue-green glow. Seeing the possibilities, [Sam] designed a PCB with cutouts in the copper and solder mask in the shape of a traditional seven-segment display. The backside of the PCB has pads for UV LEDs and current-limiting resistors, which shine through the board and induce the segments to glow. Through-slots between the segments keep light from one segment from bleeding over into the next; while [Sam] left the slots unfilled, they could easily be filled with solder. The fluorescent property of FR-4, and therefore the brightness and tint of the segments, seems to vary by board thickness and PCB manufacturer, but it looks like most PCBs will show pretty good results.

We’d say the obvious first improvement might be to cover the back of the display with black epoxy, to keep stray light down, and to improve contrast. But they look pretty great just as they are. We can also see how displays with other shapes, like icons and simple symbols. Or maybe even alphanumeric characters — say, haven’t we seen something like that before?

The Pi 400 As A PC Peripheral

October 16, 2021 by Jenny List 15 Comments

The Raspberry Pi 400 all-in-one computer is a neat little unit that is powerful enough to take on most humdrum computing tasks while doing an excellent job of freeing up valuable desktop space. But what about those moments when both the Pi and a PC are needed on the same desktop? How can the Pi and the bulky PC keyboard share the same space?

[Gadgetoid] may have the answer, with a clever bit of software that presents the Pi’s mouse and keyboard as peripherals on its USB-C power port. If your PC has a high-power USB socket that can run the Pi then it can use the small computer’s input devices just as well as the Pi itself can. It’s fair to say that the Pi 400’s keyboard is not it’s strongest point, but we can see some utility in the idea.

Running it is simply a case of running an executable from the Pi. Control can be wrested back to Raspberry Pi OS with a simple keystroke. Perhaps it’s not the ultimate desktop experience, but if you’re a die-hard Pi-head there’s plenty of appeal.

Within a few weeks, it’s a year since the launch of the Pi 400. We’ve not seen as many of them as the other Pi models, but you might find our original review to be of interest.

Thanks [Itay] for the tip.

Learn DMX512 Basics

October 15, 2021 by Al Williams 11 Comments

If you’ve done anything with modern lighting effects, you’ve probably heard of DMX, also known as DMX512. Ever wonder what’s really happening under the hood? If so, then you should have a look at [EEForEveryone’s] video on the topic, which you can see below.

At the core, the DMX512 uses RS485, but adds software layers and features. The video uses the OSI model to show how the system works.

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Better History Through X-Rays

October 15, 2021 by Al Williams 7 Comments

Even if you aren’t a giant history buff, you probably know that the French royal family had some difficulties in the late 1700s. The end of the story saw the King beheaded and, a bit later, his wife the famous Marie Antoinette suffered the same fate. Marie wrote many letters to her confidant, and probable lover, Swedish count Axel von Fersen. Some of those letters have survived to the present day — sort of. An unknown person saw fit to blot out parts of the surviving letters with ink, rendering them illegible. Well, that is, until now thanks to modern x-ray technology.

Anne Michelin from the French National Museum of Natural History and her colleagues were able to foil the censor and they even have a theory as to the ink blot’s origin: von Fersen, himself! The technique used may enable the recovery of other lost portions of historical documents and was published in the journal Science Advances.

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OAK-D Depth Sensing AI Camera Gets Smaller And Lighter

October 15, 2021 by Donald Papp 9 Comments

The OAK-D is an open-source, full-color depth sensing camera with embedded AI capabilities, and there is now a crowdfunding campaign for a newer, lighter version called the OAK-D Lite. The new model does everything the previous one could do, combining machine vision with stereo depth sensing and an ability to run highly complex image processing tasks all on-board, freeing the host from any of the overhead involved.

Animated face with small blue dots as 3D feature markers. — An example of real-time feature tracking, now in 3D thanks to integrated depth sensing.

The OAK-D Lite camera is actually several elements together in one package: a full-color 4K camera, two greyscale cameras for stereo depth sensing, and onboard AI machine vision processing with Intel’s Movidius Myriad X processor. Tying it all together is an open-source software platform called DepthAI that wraps the camera’s functions and capabilities together into a unified whole.

The goal is to give embedded systems access to human-like visual perception in real-time, which at its core means detecting things, and identifying where they are in physical space. It does this with a combination of traditional machine vision functions (like edge detection and perspective correction), depth sensing, and the ability to plug in pre-trained convolutional neural network (CNN) models for complex tasks like object classification, pose estimation, or hand tracking in real-time.

So how is it used? Practically speaking, the OAK-D Lite is a USB device intended to be plugged into a host (running any OS), and the team has put a lot of work into making it as easy as possible. With the help of a downloadable application, the hardware can be up and running with examples in about half a minute. Integrating the device into other projects or products can be done in Python with the help of the DepthAI SDK, which provides functionality with minimal coding and configuration (and for more advanced users, there is also a full API for low-level access). Since the vision processing is all done on-board, even a Raspberry Pi Zero can be used effectively as a host.

There’s one more thing that improves the ease-of-use situation, and that’s the fact that support for the OAK-D Lite (as well as the previous OAK-D) has been added to a software suite called the Cortic Edge Platform (CEP). CEP is a block-based visual coding system that runs on a Raspberry Pi, and is aimed at anyone who wants to rapidly prototype with AI tools in a primarily visual interface, providing yet another way to glue a project together.

Earlier this year we saw the OAK-D used in a system to visually identify weeds and estimate biomass in agriculture, and it’s exciting to see a new model being released. If you’re interested, the OAK-D Lite is available at a considerable discount during the Kickstarter campaign.