Filament Dry Box Design Goes Way Over The Top

February 15, 2022 by Dan Maloney 36 Comments

There’s a fine line between simple feature creep and going over the top when it comes to project design. It’s hard to say exactly where that line is, but we’re pretty sure that this filament dry box has at least stepped over it, and might even have erased it entirely.

Sure, we all know the value of storing 3D printer filament under controlled conditions, to prevent the hygroscopic plastics from picking up atmospheric moisture. But [Sasa Karanovic] must really, REALLY hate the printing artifacts that result. Starting with a commercially available dry box that already had a built-in heating element, [Sasa] took it to the next level by replacing the controller and display with an ESP32. He added a fan to improve air circulation inside the enclosure and prevent stratification, as well as temperature and humidity sensors. Not satisfied with simply switching the heating element on and off at specific setpoints, he also implemented a PID loop to maintain a constant temperature. And of course, there’s a web UI and an API available for third-party control and monitoring.

The video below details [Sasa]’s design thoughts and goes into some detail on construction and performance. And while we may kid that this design is over-the-top, what really comes through is that this is a showcase for design ideas not only for one application, but for hardware projects in general. There are certainly simpler heated dry box designs, and zero-cost solutions as well, but sometimes going overboard has its own value too.

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No LEDs Required For This Servo-Controlled Larson Scanner

February 13, 2022 by Dan Maloney 31 Comments

All things considered, it’s pretty easy to get one LED is a strip to light up sequentially, and have it bounce back and forth. Turning that simple animation into a real Larson scanner, with smooth transitions and controlled fade-out, is another thing entirely. And forgetting the LEDs altogether and making a servo-operated Larson scanner is — well, let’s just call it an interesting lesson in hardware abstraction.

The Larson scanner, named after famed TV producer Glen A. Larson for his penchant for incorporating it into shows like Battlestar Galactica and Knight Rider, is actually hard to execute in hardware thanks to the fading tail that follows the lead pixel as it dances back and forth across the display. [Eric Gunnerson] decided to make this and other animation effects easier to achieve with Fade, a custom framework for LED animations that runs on an ESP32.

LED animations are fine, but what about servos? Could Fade be modified to support them? This turned out to be a fairly easy mod thanks to Fade’s architecture and [Eric]’s existing support for non-addressable LEDs via PWM signals. And it was even possible to support more than the 16 PWM channels on an ESP32by adding a UDP connection that puts multiple ESP32s under the control of a central microcontroller.

The video below shows [Eric]’s demo of servo support, with an eight-channel electromechanical Larson scanner. Each “pixel” is a painted ping pong ball swinging back and forth on a hobby servo, and the whole thing sounds just about as awful as you’d expect it to. If you squint just right, the effect looks pretty convincing, but that’s hardly the point. The real story here is [Eric]’s thoughtful architecture, which made the mods easier than starting from scratch.

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That Clock On The Wall Is Actually A Network Ping Display

February 9, 2022 by Dan Maloney 15 Comments

We’ve all been online from home a bit more than usual lately, in ways that often stretch the limits of what our ISP can muster. You know the signs — audio that drops out, video sessions that make you look like [Max Headroom], and during the off-hours, getting owned in CS:GO by pretty much everyone. All the bandwidth in the world won’t make up for high latency, and knowing where you stand on that score is the point of this ping-tracking clock.

This eye-catching lag-o-meter is courtesy of [Charl], who started the build with a clock from IKEA. Stripped of pretty much everything but the bezel, he added a coaxial clock motor and a driver board, along with a custom-printed faceplate with logarithmic scale. The motors are driven by an ESP32, which uses internet control message protocol (ICMP) to ping a trusted server via WiFi, calculates the proper angles for the hands, and drives the motors to show you the bad news. There’s also an e-paper display in the face, showing current server and WiFi settings.

We really like how this clock looks, and if it wasn’t for the fact that the numbers it displays would often be too depressing to bear, we’d build one in a snap. If facing the painful truth isn’t your style, there are other neat ICMP tricks that you can try instead.

Long Range Burglar Alarm Relies On LoRa Modules

January 28, 2022 by Lewin Day 15 Comments

[Elite Worm] had a problem; there had been two minor burglaries from a storage unit. The unit had thick concrete walls, cellular signal was poor down there, and permanent wiring wasn’t possible. He thus set about working on a burglar alarm that would fit his unique requirements.

An ESP32 is the heart of the operation, paired with a long-range LoRa radio module running at 868 MHz. This lower frequency has much better penetration when it comes to thick walls compared to higher-frequency technologies like 4G, 5G or WiFi. With a little coil antenna sticking out the top of the 3D-printed enclosure, the device was readily able to communicate back to [Elite Worm] when the storage unit was accessed illegitimately.

With an eye to security, the device doesn’t just warn of door open events. If signal is lost from the remote transmitter in the storage unit, perhaps due to an advanced adversary cutting the power, the alarm will also be raised. There’s still some work to be done on the transmitter side, though, as [Elite Worm] needs to make sure the door sensor is reliable under all conditions.

Many put their hardware skills to work in service of security, and we regularly see proprietary alarm systems modified by enterprising hackers. Video after the break.

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Recreating MS Paint For The ESP32

January 27, 2022 by Lewin Day 11 Comments

Microsoft Paint was one of the first creative outlets for many children when they first laid hands on a computer in the 1990s. Now, [Volos Projects] has brought the joy of this simple application to a more compact format on the ESP32!

The GUI is a fair bit simpler than even the Windows 3.1 version of MS Paint, looking a little more like something from the very early GUI era. Regardless, one can draw simple shapes in block colors just like the old days, with a pair of potentiometers to move the cursor and twin tactile buttons for selecting tools and committing changes to the canvas.

The build shows that even a 1.3″ 240×240 TFT display can display some charming, colorful graphics, and realistically it’s not far off the resolution most computers had in the late 80s anyway. We’d love to see the software get some more tools too, like the spray can and brushes that were such a key part of the MS Paint experience. Code is available for those eager to play with ES Paint 32 for themselves.

It bears noting that despite some claims to the contrary, MS Paint isn’t dead. Incidentally, if you’re a masochist, you can even program in everybody’s favorite Windows-bundled art program. Video after the break.

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Pocket-Sized Doom Is Actually Playable

January 26, 2022 by Lewin Day 19 Comments

It used to be that you needed a well-equipped expensive new beige-box PC if you wanted to play Doom at all. Now, you can do so in a form factor with a footprint smaller than a credit card, as demonstrated by this nifty little build from Adafruit.

The build relies on the Retro-Go firmware for ESP32 devices, which can emulate a range of machines, from the Nintendo NES and Game Boy to the NEC PC Engine, Atari Lynx, and, yes, Doom itself. It can even run Doom mods, via the WAD architecture used by the game.

It was a simple matter of porting Retro-Go to run on the tiny QT Py ESP32 Pico board, and everything fell into place. With six tactile buttons, it’s capable of not just running Doom, but running it at full playable speeds including that classic soundtrack. The 1.3″ 240×240 screen looks surprisingly crisp and does a great job of displaying the game while keeping everything readable.

It’s one of the smaller Doom-capable portables we’ve seen; we reckon you could stuff this in the change pocket in your jeans if you tried hard enough. We’ll never quite get over seeing the world’s most loved FPS running on commercial kitchen hardware, though. Video after the break.

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Pen Plotter From PCB Panels

January 21, 2022 by Chris Lott 6 Comments

Hacker [12344321A] has built a clever open-source pen plotter having a frame made from odd-shaped PCB panels (Chinese). It holds an ordinary drafting pen and draws on a small writing platform 8 x 8 cm square. This is barely enough space to draw a business card, depending on which country you’re from. The motion appears to be provided by DVD stepper motor head positioning assemblies, and the controller is an ESP32-based GRBL 3-axis board. User control is via WiFi and the plotter can be seen in operation being driven from the user’s smartphone (see video on the project page above).

Linear Motion Assemblies from a DVD player?

This looks like it would be an inexpensive build, and seems sturdy enough despite being literally held together by solder and paper clips. But be forewarned, the project is documented on an open-source hardware sharing site sponsored by EasyEDA called OSHWHub — the Chinese equivalent of their similar English-language OSHWLab. Hence all the notes are in Chinese, although Google translate can help here. [12344321A] provides all the engineering design files under GPL 3.0 license.

Thanks to [J. Peterson] for finding this project and bringing it to our attention via the tip line.