Putting Version 7.1 Of The Direct Granules FDM Extruder Through Its Paces

May 23, 2026 by Maya Posch 11 Comments

Whether you’re using granules or filament, FDM printing relies heavily on a consistent flowrate of the extruder. This is also the challenge with [HomoFaciens]’s direct granule extruder. Version 7.1 here refines some parameters before being put through a number of printing tests to see how close it comes to something you’d want to use for production.

There’s also an accompanying blog post, on which the project files can be found for those who are playing along at home.

A big part of this V7.1 change was to simplify the design for manufacturing, removing the brass insert of V7.0, instead requiring some manual labor using a drill bit and a hand reamer to get the inside of the extruder tube just right.

The section with the heating element was also extended, though this didn’t have as much of an effect as expected. During testing the overall results were actually pretty good, with the extruder able to keep up with bridging tests while the feared air bubbles from air intruding into the tube remained absent.

On the Prusa Mk4 FDM printer, there are some definite limitations on testing features like input shaping resulting in wavy patterns in some rest prints, but for upcoming tests a different FDM printer will be used which should more clearly show the potential of this extruder design.

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Unitree GO-M8018-6 Motor Reverse Engineering

May 23, 2026 by Maya Posch 9 Comments

People seem to be rather into the Unitree Go2 quadruped robot, if only for the low price tag. But perhaps more interesting are the motors that propel it — they appear to be similar to the Go1’s GO-M8010-6 motors that Unitree also sells, with [Thomas Flayols] currently working on reverse-engineering its proprietary driver using the publicly available documentation for that motor and some reverse-engineering.

These motors are an assembly that includes a reducer, magnetic encoder, 3-phase inverter, current sensing, an RS-485 bus and a Cortex-M0-based CMS32M57xx MCU, all in a very capable package intended for robotics applications where a compact actuator is needed.

The first step of reverse-engineering involved the physical PCB, made all the more difficult as Unitree was so kind as to remove all markings on the ICs. Fortunately using an X-ray machine and some sleuthing it was possible to deduce the MCU and other components. Following this SWD/OpenOCD access to the MCU could be established and the firmware key extracted from the bootloader SRAM.

Although the firmware was encrypted, a locally recovered key was found to decrypt it. This allowed for an initial custom firmware to be developed, which [Thomas] hopes to develop into a fully featured open source firmware. Doing so would obviously open these motors to a larger audience outside of Unitree’s ecosystem, as they are pretty good value for what they offer mechanically.

It might give the associated Go2 robot a new life too considering the serious malware accusations and security issues pertaining to its firmware.

Improving An Aquarium Chiller With An Industrial Controller Transplant

May 22, 2026 by Maya Posch 7 Comments

A healthy aquarium ecosystem requires very specific conditions, with factors like the salinity and temperature having to be just right to keep said ecosystem happy. As some species are adapted to fairly cold water, this requires the use a water chiller. Recently [The Blunt Oracle] modified one of these aquarium-focused chillers with a much better controller to make it both more accurate and potentially more efficient as well.

The target for the surgery was a generic Shanhuchong Y-160 chiller that after a brief teardown turned out to use an STC-1000 style controller. The biggest disadvantage with this unit is probably that it just has one temperature probe, which monitored the temperature of the heat exchanger rather than that of the chilled water tank.

This controller was replaced with a Wi-Fi-equipped Elitech ECS-974T sourced for $50 off AliExpress that uses the same 71 x 29 mm form factor. Following that it was just a matter of some creative rewiring – as shown in the top image – and installing the twin temperature probes of the new controller.

Being able to monitor also the temperature of the chilled water adds a layer of redundancy that’s very welcome after splurging thousands of clams on a fancy aquarium and its inhabitants. As a bonus the Wi-Fi interface allows for it to be monitored and controlled remotely, with [The Blunt Oracle] pushing the Home Assistant configuration in a PR as well that recently got merged. They’d also like to extend their thanks to Elitech for having pretty good documentation that really helped with creating the HA configuration file, which is a rarity with many of such controllers.

How The Banana Pi BPI-R4 Pro Violates The First Rule Of OpenWRT Club

May 22, 2026 by Maya Posch 7 Comments

As fun as ARM and RISC-V single-board computers (SBCs) are, all too often getting the most out of the hardware requires the use of an unofficial firmware image. So too with the Banana Pi BPI-R4 Pro router SBC that has been out for a while, as OpenWRT support for it still very much unofficial. This is where [Interfacing Linux] goes on a bit of a rant while assembling one of these puppies into a sleek metal enclosure.

The first rule of OpenWRT Club is of course that you never run an unofficial image on any hardware that’s part of any network you care about. This is somewhat upsetting, as the testing shown in the video below reveals that performance is great when running it.

Currently OpenWRT support is painfully working its way through development, per the OpenWRT PR thread, so there’s hope that official support will appear at some point. As with all of such SBCs the question is always whether official support appears before the hardware has been rendered firmly obsolete. Until then the community Debian 13 image might actually be safer.

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Why The Smart Home Bubble Popped

May 21, 2026 by Maya Posch 108 Comments

Circa 2015 or so, it seemed like you couldn’t move a finger without being bombarded with ads and articles about ‘smart homes’ and the ‘internet of things’ — all of which would make our lives so much easier and more automated. Fast-forward a decade and this dream has mostly evaporated along with many of the players in the space. Why this happened is the topic of a recent video by [Caya].

An interesting bit of context that the video starts off with is that home automation really kicked off back in 1975, when the X10 protocol and related devices using power lines for signaling began being sold. These fully integrated solutions generally worked reasonably well, but what all changed when the IoT and ‘smart home’ craze kicked off and brought with it an explosion of new standards.

Over the past decade we have seen the concept of a ‘smart home’ collapse into a nightmare of abandoned IoT devices, subscription services, forced ads, privacy violations, and an increasingly more congested 2.4 GHz spectrum that everything from WiFi and Zigbee to Bluetooth and others ended up competing for, with a corresponding collapse in reliability of data transmissions.

As raised in the video, a big issue is that of the financial viability of running the remote services for a smart home solution, even if this is the part that should make it as plug-and-play as a 1990s-era smart home solution. To the average user setting up their own locally hosted smart home solution isn’t really a straightforward option.

Although at the end [Caya] demonstrates using Home Assistant (HA) as a locally hosted alternative, this is still not something that a non-techie will be able to set up or maintain. Even if you shell out a cool two-hundred clams for the Home Assistant Green plug-and-play hardware solution, the average person will be lost the second any of the prescribed steps in provided documentation do not work. Woe to whoever is the person who is ‘good with computers’ in those cases.

Ultimately another problem with ‘smart homes’ is that they’re really not that smart, as you can definitely set up all kinds of rules in HA and similar solutions, but this is more painstaking manual automation with all the excitement of programming PID controllers. Having an actual intelligence behind the system that could react to what’s happening would make it a far easier sell, yet which is where all the ‘smart assistants’ like Alexa keep falling flat.

Currently [Caya] has set up his HA-based lighting configuration to be used by OpenClaw ‘agentic AI’, as a way to add some actual ‘smarts’, but it’s telling that he hasn’t integrated the smart lock of his apartment into the system yet. Nobody wants to have the OpenClaw agent tell you that it ‘cannot open the front door’ for you, after all.

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Investigating The Health Impacts Of UFPs And VOCs From FDM Printers

May 20, 2026 by Maya Posch 22 Comments

FDM 3D printing is fairly messy on a molecular scale, with the filament being heated up to temperatures high enough to melt it, which produces ultra-fine particles (UFPs) and volatile organic compounds (VOCs) in addition to the new plastic item on the build plate. Recently [Simon Pow] got somewhat worried about this pollution considering that he spends a considerable amount of time in the same room as FDM printers, sharing air.

While there is a lot of context within the topic, it’s notable that even ‘low risk’ PLA already emits formaldehyde, a group 1 carcinogen. Studies like this 2022 one by [Taehun Kim] et al. on formaldehyde, PM10 and PM2.5 show that common filaments like PLA, ABS and TPU score pretty bad here, even compared to the often maligned resin printing, also in the study. Having good ventilation in a room helps a lot, but it doesn’t reduce the levels to zero.

As noted by [Simon], PETG is much better in the VOC area, while TPU emits siloxanes, some of which are dangerous but most are considered harmless. Once you hit nylon (e.g. PA6), you’re adding caprolactam, which is mildly toxic but mostly just an irritant. Where things get serious is with ABS and ASA, when you add styrene to the mix. This substance is very dangerous, being toxic, mutagenic and possibly carcinogenic, but on the plus side it smells kind of sweet.

Polycarbonate (PC) emits BPA, with its worrying long-term health implications, while carbon fibers in particular can have asbestos-like long-term effects, as we covered previously. Definitely wear PPE while doing things like sanding CF parts and safely dispose of any debris.

Of course, you can do something about this problem, such as having an enclosure around the printer, with HEPA filtration and activated carbon, potentially exhausting into the outside air. The options here are covered in the video, including a BentoBox filter. For [Simon] the biggest improvement – as measured by a whole room sensor – came from a big fan in the window, while the default activated carbon filter in the Bambu Lab printer did effectively nothing.

The problem here is mostly one of long-term exposure, so even basic precautions like filtration and ventilation can already make all the difference. Ideally you’d not have the printer in the same room as where you work, of course, but adding a good filtration setup doesn’t have to be expensive or hard.

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A DIY 3D Printing Filament Dryer

May 20, 2026 by Maya Posch 23 Comments

In a recent video [Saša Karanović] revisits the DIY filament dryer that he gave a shot a couple of years ago. Back then he reused an existing filament dryer, adding a custom controller and such to improve its performance.

This technically-not-fully-DIY dryer got some feedback since then, and thus the V2 version is an example of how to better DIY such a dryer, including a custom PCB and a GitHub project for all the details.

Those who just want to dive into the documentation for assembly and the BOM can look at the available documentation. At its core the whole assembly consists of some kind of container like the shown 5L food storage type, along with an SHT30 temperature and humidity sensor and 100 K NTC temperature sensor. These connect to the controller board which then switches on or off the 12 V polyimide resistive heater.

One thing that could be improved here is that the saturated warm air has nowhere to go. This is a common issue with filament dryers and why it’s recommended with even commercial filament dryers like the common Sunlu types to leave them slightly ajar so that the moist air can be replaced with cooler air that can much more readily absorb moisture.

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