A Hot End And Material Database For 3D Printing

August 18, 2026 by 2 Comments

When it comes to 3D printing in the FDM world, you can go a long way just relying on standard settings that ship with your 3D printer and/or slicer. If you want to push the limits, though, it pays to better understand the hardware and materials you’re working with to know what you can get away with. To that end, [Robert Samples] put together the MeltCalc database to help. 

The purpose of MeltCalc is simple—it collates data on hot ends and materials regarding factors like maximum flow rate, print speeds, and heater requirements. If you’re wondering whether a given hot end can flow a given filament at a given rate, for example, this tool is a great place to start. It features 64 different hot ends and 36 polymers typically used in the 3D printing world, and can spit out maximum flow rates and print speed estimations even accounting for fancy tech like Core Heating Technology (CHT) nozzles. It’s all based on thermodynamic modelling which [Robert] put together based on his experience as a chemist who works with polymers. His aim was to provide a tool with realistic flow rates for hot ends, so that end users don’t have to just rely on often-optimistic marketing numbers.

For those eager to dive deeper into the code and modelling, the project source is available on Github. We’ve featured all kinds of other useful hacks in this space lately, too, like our recent look at how to achieve wave overhangs. If you’ve got your own nifty 3D printing tools in the works, don’t hesitate to notify the tipsline.

Reverse Engineered Grill Controller Gets Open Firmware

August 18, 2026 by 2 Comments

If you are a regular reader, then the odds are you have taken apart an electronic gadget, either for a fix, or simply because your curiosity got the better of you. Once inside, it’s all but impossible to help yourself from doing at least a little reverse engineering. That’s what happened when [PRBS23] took a look inside a Gravity 800 Grill for a simple wire fix. But one thing led to the next, and now open source firmware for the grill is freely available!

Control board schematic.
Control board schematic.

The first order of business in creating the firmware is reverse engineering the original controller. Opening it up immediately reveals an ESP-32 and a well-labeled programming port. The rest of the control board is equally simple, including connectors for four thermistor temperature sensors, lid open/close switch, fan driver, 16 segment LCD, piezo buzzer, and some physical inputs.

The thermistor along with the physical inputs are connected to a 16 pin chip, interfacing with the MCU over a 9600 baud UART connection. [PRBS23] cannot determine an ADC chip meeting these specifications, so the most likely answer is a cheap MCU programmed to act as a simple analog fronted.

The neatly labeled programming header is used to quite easily dump the firmware with the espflash utility. Analyzing this dump reveals a rather strange ADC correction function used by the original firmware. The necessity and overall utility of this function remains unclear, does corrects a maximum of around 40 degrees Fahrenheit.

Most of the other features ended up being at least somewhat easier. The CS1621 segmented display driver is reasonably well documented with datasheets making its implementation far easier. Likewise, the other odds and ends were implemented in a far more normal manner compared to the thermistors.

All this reverse engineering work got tied together into a neat little firmware package. It comes with over the air updates PID controlled temperature, and a real-time web interface. This also isn’t the first time we have seen an IoT device liberated from proprietary firmware, and this remains one of our favorite uses of reverse engineering!

 

An open-source, DIY, point-and-shoot digital camera.

PolyShot Camera Focuses On Nostalgia

August 18, 2026 by 1 Comment

Although we personally have yet to see anyone brandishing an old digital point-and-shoot camera, we hear they’re back in vogue. Why, though? People are nostalgic for that image quality. While he certainly could have simply picked up a vintage model somewhere for a likely inflated price, [Arnov Sharma] decided to build his own version and call it the PolyShot.

The core of this project is the Unihiker K10 dev board, which uses an ESP32-S3, a whopping 2 megapixel camera, and a micro SD card to capture photos and display them back on the screen. The tricky part, if you can call it that, is the custom PCB. It’s a simple board with just three buttons: shutter, gallery, and next image. We do like that the position of the battery compartment creates a nice grip.

The biggest difference here is that there is a few-second delay between pressing the shutter button and actually capturing the image, which you can see in the short videos below. So if you’re trying to get a shot of a skink or something equally speedy, we wish you good luck.

In a future iteration, [Arnov] wants to address the issue of image quality, because this project ended up evolving into a more traditional digital camera. He would also improve the battery life, for which the current expectancy is around three hours on a charge. Ultimately, [Arnov] wants to ditch the Unihiker and design everything from the ground up, using an ESP32-S3 module.

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Announcing The 2026 Hackaday Retrocomputing Challenge

August 18, 2026 by 2 Comments

What is it about retrocomputing? For some people, it’s nostalgia. For others, it’s the appeal of simplicity. For still others, it’s the chance to save old machines from the graveyard. Whatever your motivation, there’s no denying that we’ve seen a metric ton of retrocomputer projects here at Hackaday. And we’d like to see more!

We’re happy to announce the 2026 Hackaday Retrocomputing Challenge!

Now’s the chance to put your retrocomputer project up for all to see. Open up a Hackaday.io project that features your retrocomputer project, and we’ll pick our three favorites for a $150 gift certificate courtesy of this contest’s sponsor, DigiKey. You have until Tuesday, October 27th. So get hacking!

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So, You Want To Fix An Old Camera

August 18, 2026 by 9 Comments

Old cameras are a fantastic way to experiment with photography, and outside a few brands, they can be an inexpensive way too. It’s easy to find older cameras in a broken condition for  a lot less money, but if you’re tempted to fix one then [enthdegree] has some advice for you.

It’s ostensibly a set of notes on the disassembly and repair of a Nikon F100 35mm film SLR, but along the way it’s full of useful tips and tricks for camera disassembly. he materials you’ll need, advice on not losing screws is one, and warnings against disassembling too much is another. It’s all the stuff he wished he’d known before starting, and now you can know it too.

Fixing up old cameras in this way is rewarding, and something we’ve certainly been known to do ourselves. But it’s worth bearing in mind that it’s not for the faint-hearted, and with decades of old film cameras sitting unused, often a working example might make more sense.

Smartphones And The Next Generation Of Hearing Aids

August 18, 2026 by 11 Comments

If you don’t actually need one, you’d be forgiven for thinking a hearing aid just makes everything louder for the wearer. Especially since there are plenty of shady products out there which will do exactly that for just four easy payments of $29.99. But the reality is considerably more complex, as a proper hearing aid needs to be capable of selectively enhancing certain frequencies while squashing down others.

The technical challenges involved in pulling that off in a device small enough to fit inside the human ear and run off of a tiny battery are considerable — and while there’s undoubtedly been some degree of artificial price inflation going on over the years, there’s a reason proper hearing aids have been so much more expensive than their “As Seen on TV” counterparts. These same challenges are also why DIY and open source hardware hearing aids have struggled to gain much traction.

But over the last few years the situation has changed. In 2022 the United States Food and Drug Administration (FDA) established the framework by which hearing aids could be sold over the counter (OTC). Although they’re generally less capable than their prescription counterparts and not suitable for individuals with profound hearing loss, the wide commercial availability of OTC hearing aids has kicked off a competition between manufacturers to deliver more affordable devices.

That competition entered a new phase earlier this month when the FDA granted approval for Samsung’s Galaxy Earbuds to fall under the same category. This follows a similar decision made about Apple’s AirPods back in 2024. The two biggest players in the smartphone market being able to offer their earbuds as OTC hearing aids represents a unique value proposition. Not only are they priced for mass market consumption, but many individuals who would be interested in purchasing an OTC hearing aid will already own them and need only to enable the feature with a software update.

Given how different the situation is today than even just five years ago it’s worth asking just what qualifies as a over-the-counter hearing aid, and how the shifting definition of these devices can inform the community’s efforts to develop open hardware solutions.

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Watch Soldering Up Close And From Any Angle, In VR

August 18, 2026 by 19 Comments

A manual skill like soldering is so much easier to learn and grasp when one can watch it in action, and there’s a brand new way to do that using virtual reality (VR). It isn’t just a series of 3D videos shot at someone’s workbench, either.

See soldering in action from any angle, with fine details preserved even close up.

PCB Hand-Soldering Basics is a series of thirteen videos that demonstrate soldering using Gaussian splats, a method of displaying 3D content that allows the viewer to freely look at things from any angle. Gaussian splats aren’t new, but what makes this different is the sheer level of detail and the fact that it’s focused on handheld tool use rather than displaying a famous location, landmark, or something similarly “big”.

Throughout the videos fine detail on the iron, parts, and the PCB itself remain visible from any angle and even from close up. Here’s a short video captured from within a VR headset that is probably the next best thing to seeing it yourself.

An educational production, it was was made in cooperation with the Department of Electrical and Electronic Engineering at Imperial College London. A few more details are in a LinkedIn post by [Tanmay Lad], who was part of the team involved in the production. The goal is to offer a unique, front-row seat to hand soldering with the ability to zoom in or look at it in 3D from any angle.

Not familiar with Gaussian splats? We’ve previously covered a great overview. They look great and are computationally cheap to render, and being able to get up close and see such detail is not really something one expects.