Building A 3D Printed Phone Handset With Mil-Spec Style

December 28, 2024 by Tom Nardi 14 Comments

In general, military gear is designed to be rugged and reliable. A side effect of this is that the equipment usually has a distinct visual look that many people find appealing. You might not need a laptop that can survive being in a war zone, but plenty of hackers have picked such machines up on the second hand market anyway.

Case in point, the H-250 telephone handset. [Tobias] didn’t actually need a combat-ready phone handset, but loved the way it looked. Technically you can pick these up on eBay for a reasonable price, but then you’ve still got to deal with the weirdo military components inside it. So why not design a look-alike and 3D print it?

[Tobias] came up with a design in OpenSCAD that has a very close resemblance to its military counterpart. Not only has he made the source code for the 3D model available for others who might want to print their own look-alike handset, but the Hackaday.io page also includes a breakdown of the hardware that needs to be added to the printed parts to make it a functional handset.

If you think the H-250 handset looks familiar, it’s probably because it comes standard issue on the TA-1042 field telephone — another very slick looking piece of military gear that we’ve covered previously.

FallingWater Clock Puts New Spin On A Common LCD

December 27, 2024 by Tom Nardi 4 Comments

Sometimes, all it takes is looking at an existing piece of tech in a new way to come up with something unique. That’s the whole idea behind FallingWater, a gorgeous Art Deco inspired clock created by [Mark Wilson] — while the vertical LCD might look like some wild custom component, it’s simply a common DM8BA10 display module that’s been rotated 90 degrees.

As demonstrated in the video below, by turning the LCD on its side, [Mark] is able to produce some visually striking animations. At the same time the display is still perfectly capable of showing letters and numbers, albeit in a single column and with noticeably wider characters.

In another application it might look odd, but when combined with the “sunburst” style enclosure, it really comes together. Speaking of the enclosure, [Mark] used OpenSCAD to visualize the five layer stack-up, which was then recreated in Inkscape so it could ultimately be laser-cut from acrylic.

Rounding out the build is a “Leonardo Tiny” ATmega32U4 board, a DS3221 real-time clock (RTC), a couple of pushbuttons, and a light dependent resistor (LDR) used to dim the display when the ambient light level is low. All of the electronics are housed on a small custom PCB, making for a nicely compact package.

This build is as simple as it is stylish, and we wouldn’t be surprised if it inspired more than a few clones. At the time of writing, [Mark] hadn’t published the source code for the ATmega, but he has provided the code to generate the cut files for the enclosure, as well as the Gerber files for the PCB. If you come up with your own version of this retro-futuristic timepiece, let us know.

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Playing Around With The MH-CD42 Charger Board

December 27, 2024 by Tom Nardi 12 Comments

If you’ve ever worked with adding lithium-ion batteries to one of your projects, you’ve likely spent some quality time with a TP4056. Whether you implemented the circuit yourself, or took the easy way out and picked up one of the dirt cheap modules available online, the battery management IC is simple to work with and gets the job done.

But there’s always room for improvement. In a recent video, [Det] and [Rich] from Learn Electronics Repair go over using a more modern battery management board that’s sold online as the MH-CD42. This board, which is generally based on a clone of the IP5306, seems intended for USB battery banks — but as it so happens, plenty of projects that makers and hardware hackers work on have very similar requirements.

So not only will the MH-CD42 charge your lithium-ion cells when given a nominal USB input voltage (4.5 – 5 VDC), it will also provide essential protections for the battery. That means looking out for short circuits, over-charge, and over-discharge conditions. It can charge at up to 2 A (up from 1 A on the TP4056), and includes a handy LED “battery gauge” on the board. But perhaps best of all for our purposes, it includes the necessary circuitry to boost the output from the battery up to 5 V.

If there’s a downside to this board, it’s that it has an automatic cut-off for when it thinks you’ve finished using it; a feature inherited from its USB battery bank origins. In practice, that means this board might not be the right choice for projects that aren’t drawing more than a hundred milliamps or so.

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Open Source Lemontron 3D Printer Is Ready To Build

December 26, 2024 by Tom Nardi 19 Comments

In this era of cheap turn-key machines, the idea of actually building your own desktop 3D printer might seem odd to some. But if you’re looking for a challenge, and want to end up with a printer that legitimately sets itself apart from what they’re stocking on Amazon these days, then take a look at the Lemontron.

We’ve been keeping tabs on the development of this open source 3D printer for some time now, and just before Christmas, the files finally were released for anyone who wants to try putting one together themselves. There’s currently no formal kit available, but once you’ve printed out all the parts, there’s a very nice bill of materials you can find on the website which will tell you everything you need to complete the assembly — and critically — where you can get it.

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Open Source Multimeter Raises The Bar For DIY Tools

December 25, 2024 by Tom Nardi 39 Comments

Whether you only dabble in electronics as a hobby or it’s your full-time job, there are few tools as indispensable as the multimeter. In fact, we’d be willing to bet nearly everyone reading this site owns at least one of them. But as common and mindbogglingly useful as they may be, they aren’t perfect. Even the high-end models will invariably have some annoyance that only reveals itself once you become intimately acquainted with it.

Most people would just live with those quirks, especially when dealing with a cheaper model. But not [John Duffy]. Deciding nothing but perfection would do, he took every favorite feature he’d ever run into while using other multimeters and combined them into his scratch-built HydraMeter. In the process, he managed to come up with a few new ideas that push this device into a league of its own.

Some of the features of the HydraMeter will look familiar. You might even have them on your own personal meter, such as the wireless removable display module. Other features you’ll wish your meter had, such as the removable cartridge on the front of the device that lets you rapidly swap out a burned fuse. On the other side of the spectrum, there are some esoteric features that might leave you scratching your head. The ability to tell exactly how the meter is configured at a glance thanks to its exclusive use of toggle switches has a certain hacker appeal, but it’s a tricky user interface for most folks.

While the overall design of the HydraMeter may be divisive, one thing we can all agree on is that getting the project to this state took incredible determination. Over the years we’ve only seen a handful of individuals attempt to develop their own multimeters, and even then, none of them approached this level of fit and finish. The fact that [John] has turned all that effort over to the community by releasing his design under the CERN license is truly admirable.

[John] brought the HydraMeter out to Pasadena back in November for Supercon, and it got quite a reaction. And if you don’t like the user interface, it’s not hard to imagine how you could change it. This project has unquestionably pushed the state of the art for open source multimeters forward, and we’re eager to see where it goes from here.

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Break Me Off A Piece Of That Open Source Serial Adapter

December 25, 2024 by Tom Nardi 12 Comments

We know, you’ve already got a USB to serial adapter. Probably several of them, in fact. But that doesn’t mean you couldn’t use one more — especially when it’s as as cleverly designed as this one from [Anders Nielsen].

The first thing you notice about this adapter, and the big departure from the ones that are likely littering your parts bin, is that it terminates in a full-size male DSUB9 connector. With the ability to be directly plugged into a RS-232 port, this adapter will certainly catch the eye of retrocomputer enthusiasts. With a clever arrangement of jumpers, you can even reconfigure the RX and TX lines to be straight-through or cross over as needed.

But if you’re working with something that doesn’t have a literal serial port, no worries. All of the lines coming from the CH340G chip are broken out to a header so you can connect it up to whatever device you’re working with via jumpers.

In fact, if you’re really sure you’ll never need that RS232 feature, the PCB is even designed in such a way that you can simply snap it off. Admittedly it might seem a little odd to get a device like this if you didn’t want that capability. But once broken off, it’s not like the components go to waste. [Anders] has designed the board in such a way that if you flip it over and install a right-angle header, you can use the RS232 segment on a breadboard.

But the list of features doesn’t stop there. There’s also a 3.3 V regulator on board that you can use to power external circuits, as well as breakouts for the data lines in the USB-C connector. In keeping with the theme of the device, that part of the PCB can also be snapped off if you want to use it elsewhere.

Most folks probably’ won’t need all the capabilities offered by this particular serial adapter, and that’s fine. We’re still happy that it’s out in the wild and available for the community to use and adapt as an open source project.

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Holiday Jukebox Gets ESP32, Home Assistant Support

December 24, 2024 by Tom Nardi 13 Comments

If we’ve learned anything over the years, it’s that the only thing hardware hackers love more than a device festooned with buttons is one that’s covered in LEDs — so it’s no surprise that this “Mr Christmas” jukebox caught the eye of [Roberts Retro]. But while the holiday gadget might have been mildly entertaining in its stock configuration, he quickly realized that what it really needed was an ESP32 retrofit. After all, what good are all those buttons and LEDs if you can’t bend them to your will?

For the first half of the video, [Robert] treats us to a detailed teardown of the device, which as you might imagine, is largely hollow inside. This gave him plenty of room to graft in new hardware, which is really the best gift any of us could hope to find under the tree. In addition to the ESP32 development board, the jukebox also received a number of WS2812B addressable RGB LEDs, and a DFPlayer module to handle music playback.

With all the buttons wired up to inputs on the ESP32, [Robert] can reconfigure the jukebox to do pretty much whatever he wants with just changes to the software. In the video, he demonstrates how the buttons can be used to trigger the playback of individual songs stored on the DFPlayer’s SD card, which essentially replicates it’s stock functionality. A few lines of changed code later, those same buttons can be used to control devices via Home Assistant.

To get into the holiday spirit, [Roberts Retro] shows off the completed jukebox controlling his ESP-enabled LEGO train set — another of his festive upgrades that we covered back in 2022.

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