Day: September 15, 2020

LED Art Reveals Itself In Very Slow Motion

September 15, 2020 by 9 Comments

Every bit of film or video you’ve ever seen is a mind trick, an optical illusion of continuous movement based on flashing 24 to 30 slightly different images into your eyes every second. The wetware between your ears can’t deal with all that information individually, so it convinces itself that you’re seeing smooth motion.

But what if you slow down time: dial things back to one frame every 100 seconds, or every 1,000? That’s the idea behind this slow-motion LED art display called, appropriately enough, “Continuum.” It’s the work of [Louis Beaudoin] and it was inspired by the original very-slow-motion movie player and the recent update we featured. But while those players featured e-paper displays for photorealistic images, “Continuum” takes a lower-resolution approach. The display is comprised of four nine HUB75 32×32 RGB LED displays, each with a 5-mm pitch. The resulting 96×96 pixel display fits nicely within an Ikea RIBBA picture frame.

The display is driven by a Teensy 4 and [Louis]’ custom-designed SmartLED Shield that plugs directly into the HUB75s. The rear of the frame is rimmed with APA102 LED strips for an Ambilight-style effect, and the front of the display has a frosted acrylic diffuser. It’s configured to show animated GIFs at anything from 1 frame per second its original framerate to 1,000 seconds per frame times slower, the latter resulting in an image that looks static unless you revisit it sometime later. [Louis] takes full advantage of the Teensy’s processing power to smoothly transition between each pair of frames, and the whole effect is quite wonderful. The video below captures it as best it can, but we imagine this is something best seen in person.

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Whimsical Solder Stand Moonlights As Toy 3D Printer

September 15, 2020 by 12 Comments
A few Lego pieces provide key functionality, like an articulated dispenser head.

Most of us have bent a length of solder into a more convenient shape and angle when soldering, and just sort of pushed the soldering iron and work piece into the hanging solder instead of breaking out a third hand. Well, [yukseltemiz] seems to have decided that a solder dispenser and a miniature 3D printer model can have a lot in common, and created a 1/5 scale Ender 3 printer model that acts as a solder stand and dispenser. The solder spool hangs where the filament roll would go, and the solder itself is dispensed through the “print head”.

It’s cute, and we do like the way that [yukseltemiz] incorporated a few Lego pieces into the build. A swivel and eyelet guides the solder off the roll and a small Lego ball and socket gives the dispenser its articulation, an important feature for bending solder to a more convenient angle for working. It makes us think that using Lego pieces right alongside more traditional hardware like M3 nuts and bolts might be an under-explored technique. You can see the unit in action in the brief assembly video, embedded below.

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Open-Source Robotic Arm For All Purposes

September 15, 2020 by 23 Comments

A set of helping hands is a nice tool to have around the shop, especially if soldering or gluing small components is a common task. What we all really want, though, is a robotic arm. Sure, it could help us set up glue or solder but it can do virtually any other task it is assigned as well. A general-purpose tool like this might be out of reach of most of us, unless we have a 3D printer to make this open-source robotic arm at home.

The KAUDA Robotic Arm from [Giovanni Lerda] is a five-axis arm with a gripping tool and has a completely open-source set of schematics so it can be printed on any 3D printer. The robot arm uses three stepper motors and two servo motors, and is based on the Arduino MEGA 2560 for control. The electrical schematics are also open-source, so getting this one up and running is just an issue of printing, wiring, and implementing some software. To that end there are software examples available, and they can easily be modified to fit one’s robotic needs.

A project like this could be helpful for any number of other projects, or also just as a lesson in robotics for yourself or even in a classroom, since many schools now have their own 3D printers. With everything being open-source, this is a much simpler endeavor now than other projects we’ve seen that attempted to get robotic arms running again.

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Deep-Sleep Problems Lead To Forensic Investigation Of Troublesome Chip

September 15, 2020 by 53 Comments

When you buy a chip, how can you be sure you’re getting what you paid for? After all, it’s just a black fleck of plastic with some leads sticking out of it, and a few laser-etched markings on it that attest to what lies within. All of that’s straightforward to fake, of course, and it’s pretty easy to tell if you’ve got a defective chip once you try it out in a circuit.

But what about off-brand chips? Those chips might be functionally similar, but still off-spec in some critical way. That was the case for [Kevin Darrah] which led to his forensic analysis of potentially counterfeit MCU chips. [Kevin] noticed that one of his ATMega328 projects was consuming way too much power in deep sleep mode — about two orders of magnitude too much. The first video below shows his initial investigation and characterization of the problem, including removal of the questionable chip from the dev board it was on and putting it onto a breakout board that should draw less than a microamp in deep sleep. Showing that it drew 100 μA instead sealed the deal — something was up with the chip.

[Kevin] then sent the potentially bogus chip off to a lab for a full forensic analysis, because of course there are companies that do this for a living. The second video below shows the external inspection, which revealed nothing conclusive, followed by an X-ray analysis. That revealed enough weirdness to warrant destructive testing, which showed the sorry truth — the die in the suspect unit was vastly different from the Atmel chip’s die.

It’s hard to say that this chip is a counterfeit; after all, Atmel may have some sort of contract with another foundry to produce MCUs. But it’s clearly an issue to keep in mind when buying bargain-basement chips, especially ones that test functionally almost-sorta in-spec. Caveat emptor.

Counterfeit parts are depressingly common, and are a subject we’ve touched on many times before. If you’d like to know more, start with a guide.

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Digital Expression Via Harmonica

September 15, 2020 by 11 Comments

There is a good chance you clicked on this article with a mouse, trackball, trackpad, or tapped with your finger. Our hands are how most of us interact with the digital world, but that isn’t an option for everyone, and [Shu Takahashi] wants to give them a new outlet to express themselves. Some folks who cannot use their hands will be able to use the Magpie MIDI, which acts as a keyboard, mouse, MIDI device, and eventually, a game controller. This universal Human Interface Device (HID) differs from a mouth-operated joystick because it has air pressure sensors instead of buttons. The sensors can recognize the difference between exhalation and inhalation, so the thirteen ports can be neutral, positive, or negative, which is like having twenty-six discrete buttons.

The harmonica mounts on an analog X-Y joystick to move a mouse pointer or manipulate MIDI sound like a whammy bar. [Shu] knows that a standard harmonica has ten ports, but he picked thirteen because all twenty-six letters are accessible by a puff or sip in keyboard mode. The inputs outnumber the Arduino Leonardo’s analog inputs, so there is a multiplexor to read all of them. There was not enough time to get an Arduino with enough native ports, like a Teensy, with HID support baked in. Most of the structure is 3D printed, so parts will be replaceable and maybe even customizable.

Even with two working hands, we like to exercise different hardware, but the harmonica is a nifty tool to have attached to your computer.

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Putting The Firmware In Your Firmware

September 15, 2020 by 12 Comments

Performing over-the-air updates of devices in the field can be a tricky business. Reliability and recovery is of course key, but even getting the right bits to the right storage sectors can be a challenge. Recently I’ve been working on a project which called for the design of a new pathway to update some small microcontrollers which were decidedly inconvenient.

There are many pieces to a project like this; a bootloader to perform the actual updating, a robust communication protocol, recovery pathways, a file transfer mechanism, and more. What made these micros particularly inconvenient was that they weren’t network-connected themselves, but required a hop through another intermediate controller, which itself was also not connected to the network. Predictably, the otherwise simple “file transfer” step quickly ballooned out into a complex onion of tasks to complete before the rest of the project could continue. As they say, it’s micros all the way down.

The system de jour

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Mirrored Music Machine Reflects Circadian Rhythms

September 15, 2020 by 8 Comments

Interactive artist [Daric Gill] wrote in to share the incredible electronic sculpture he’s been working on for the past year. It’s called the Circadian Machine, and it’s a sensor-enabled mindfulness music-and-lights affair that plays a variety of original compositions based on the time of day and the circle of fifths. This machine performs some steady actions like playing chimes at the top of each hour, and a special sequence at solar noon.

This cyberpunk-esque truncated hexagonal bi-pyramid first geolocates itself, and then learns the times for local sunrise and sunset. A music module made of a Feather M4 Express and a Music Maker FeatherWing fetches astronomical data and controls the lights, speakers, and a couple of motion sensors that, when tripped, will change the lights and sounds on the fly. A separate Feather Huzzah and DS3231 RTC handle the WiFi negotiation and keep track of the time.

On top of the hourly lights and sound, the Circadian Machine does something pretty interesting: it performs another set of actions based on sunrise and sunset, basically cramming an entire day’s worth of actions between the two events, which seems like a salute to what humans do each day. Check out the build notes and walk-through video after the break, then stick around for the full build video.

The internet is rife with information just begging to be turned into art. For instance, there are enough unsecured CCTV cameras around the world with primo vantage points that you can watch a different sunrise and sunset every hour of every day.

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