Most of us using desktop computers, and plenty of us on laptops, have some sort of fan or pump installed in our computer to remove heat and keep our machines running at the most optimum temperature. That’s generally a good thing for performance, but comes with a noise pollution cost. It’s possible to build fanless computers, though, which are passively cooled by using larger heat sinks with greater thermal mass, or by building more efficient computers, or both. But sometimes even fanless designs can benefit from some forced air, so [Sasa] built this system for cooling fanless systems with fans.

The main advantage of a system like this is that the fans on an otherwise fanless system remain off when not absolutely necessary, keeping ambient noise levels to a minimum. [Sasa] does have a few computers with fans, and this system helps there as well. Each fan module is WiFi-enabled, allowing for control of each fan on the system to be set up and controlled from a web page. It also can control 5V and 12V fans automatically with no user input, and can run from any USB power source, so it’s not necessary to find a USB-PD-compatible source just to run a small fan.

Like his previous project, this version is built to easily integrate with scripting and other third-party software, making it fairly straightforward to configure in a home automation setup or with any other system that is monitoring a temperature. It doesn’t have to be limited to a computer, either; [Sasa] runs one inside a server cabinet that monitors the ambient temperature in the cabinet, but it could be put to use anywhere else a fan is needed. Perhaps even a hydroponic setup.

Over at the University of Wisconsin’s Undergraduate Projects Lab (UPL) there’s been a way to check whether this room is open for general use by CS undergraduates and others practically for most of the decades that it has existed. Most recently [Andrew Moses] gave improving on the then latest, machine vision-based iteration a shot. Starting off with a historical retrospective, the 1990s version saw a $15 camera combined with a Mac IIcx running a video grabber, an FTP server and an HP workstation that’d try to fetch the latest FTP image.

As the accuracy of this system means the difference between standing all forlorn in front of a closed UPL door and happily waddling into the room to work on some projects, it’s obvious that any new system had to be as robust as possible. The machine vision based version that got installed previously seemed fancy: it used a Logitech C920 webcam, a YOLOv7 MV model to count humanoids and a tie into Discord to report the results. The problem here was that this would sometimes count items like chairs as people, and there was the slight issue that people in the room didn’t equate an open door, as the room may be used for a meeting.

Thus the solution was changed to keeping track of whether the door was open, using a sensor on the two doors into the room. Sadly, the captive-portal-and-login-based WiFi made the straightforward approach with a reed sensor, a magnet and an ESP32 too much of a liability. Instead the sensor would have to communicate with a device in the room that’d be easier to be updated, ergo a Zigbee-using door sensor, Raspberry Pi with Zigbee dongle and Home Assistant (HA) was used.

One last wrinkle was the need to use a Cloudflare-based tunnel add-on to expose the HA API from the outside, but now at long last the UPL door status can be checked with absolute certainty that it is correct. Probably.

Featured image: The machine vision-based room occupancy system at UoW’s UPL. (Credit: UPL, University of Wisconsin)

[Andre Me] has long-standing interest in automating 3D print jobs, and his latest project is automating build plate changes on the Bambu A1 Mini.

Here’s how it works: each build plate gets a sort of “shoe” affixed to it, with which attachments on the printer itself physically interact when loading new plates and removing filled ones.

When a print job is finished, custom G-code causes an attachment on the printer to wedge itself under the build plate and peel it off until it is freed from the magnetic bed, after which the finished plate can be pushed towards the front. A stack of fresh build plates is behind the printer, and the printer slips a new one from the bottom when needed. Again, since the printer’s bed is magnetic, all one has to do is get the new plate to reliably line up and the magnetic attraction does the rest.

Some methods of automating print jobs rely on ejecting the finished parts and others swap the print beds. [Andre]’s is the latter type and we do really like how few moving parts are involved, although the resulting system has the drawback of requiring considerably more table space than just the printer itself. Still, it’s not at all a bad trade-off.

Watch it in action in the two videos embedded below. The first shows a time-lapse of loading and ejecting over 100 build plates in a row, and the second shows the whole system in action printing bowls in different colors.

Standardization might sound boring, but it’s really a great underlying strength of modern society. Everyone agreeing on a way that a certain task should be done saves a lot of time, energy, and money. But it does take a certain amount of consensus-building, and at the time [JC]’s HVAC system was built the manufacturers still hadn’t agreed on a standard control scheme for these machines yet. But with a little ingenuity and an Arduino, the old HVAC system can be given a bit of automatic control.

The original plan for this antiquated system, once off-the-shelf solutions were found to be incompatible, was to build an interface for the remote control. But this was going to be overly invasive and complex. Although the unit doesn’t have a standard remote control system, it does have extensive documentation so [JC] was able to build a relay module for it fairly easily with an Arduino Nano Matter to control everything and provide WiFi functionality. It also reports the current status of the unit and interfaces with the home automation system.

While some sleuthing was still needed to trace down some of the circuitry of the board to make sure everything was wired up properly, this was a much more effective and straightforward (not to mention inexpensive) way of bringing his aging HVAC system into the modern connected world even through its non-standardized protocols. And, although agreeing on standards can sometimes be difficult, they can also be powerful tools once we all agree on them.

Over the last decade or so, we’ve been inundated with appliances with wireless or “smart” technology that is often of dubious utility. No one really needs a tablet in their refrigerator or Wi-Fi on their coffee maker. A less glamorous kitchen appliance that actually might benefit from some automation and connectivity is the garbage can, or “bin” for those speaking the Queen’s English, and [Mellow_Labs] is here to show off just how to get that done with this automatic garbage can lid.

As he explains, the real impetus behind this build is to not have to touch a dirty lid while cooking to avoid having to take time to wash one’s hands again afterwards. There are a few other design criteria as well; it has to be roommate-approved so nothing permanently attached to the lid, overly complicated, or with an unnecessary amount of wires or other fixtures. A servo with an extension sits on the lid itself, and when activated forces the lid open. A distance sensor provides basic gesture recognition and a microcontroller with wireless connectivity controls both and provides home automation integration as well. With a 3D printed case that includes a quick disconnect function for easy cleaning of the lid, the build was ready to be put into service.

The first iteration used an infrared distance sensor, but placing it by an open window caused it to continuously open and close since sunlight has the same wavelengths of light the sensor is tuned for. A quick swap with an ultrasonic sensor solved the problem, and the garbage can is working flawlessly in the kitchen now. Another appliance that is generally not targeted by off-the-shelf automation solutions is the range fume hood, but another build tackled that problem a while back.

While 3D printers have evolved over the past two decades from novelties to powerful prototyping tools, the amount of support systems have advanced tremendously as well. From rudimentary software that required extensive manual input and offered limited design capabilities, there’s now user-friendly interfaces with more features than you could shake a stick at. Hardware support has become refined as well with plenty of options including lighting, ventilation, filament recycling, and tool changers. It’s possible to automate some of these subsystems as well like [Caelestis Workshop] has done with this relay control box.

This build specifically focuses on automating or remotely controlling the power, enclosure lighting, and the ventilation system of [Caelestis Workshop]’s 3D printer but was specifically designed to be scalable and support adding other features quickly. A large power supply is housed inside of a 3D printed enclosure along with a Raspberry Pi. The Pi controls four relays which are used to control these various pieces hardware along with the 3D printer. That’s not the only thing the Pi is responsible for, though. It’s also configured to run Octoprint, a piece of open-source software that adds web interfaces for 3D printers and allows their operation to be monitored and controlled remotely too.

With this setup properly configured, [Caelestis Workshop] can access their printer from essentially any PC, monitor their prints, and ensure that ventilation is running. Streamlining the print process is key to reducing the frustration of any 3D printer setup, and this build will go a long way to achieving a more stress-free environment. In case you missed it, we recently hosed a FLOSS Weekly episode talking about Octoprint itself which is worth a listen especially if you haven’t tried this piece of software out yet.

Selling your hardware hacks is a great way to multiply your project’s impact, get your creations into others’ hands, and contribute to your hacking-related budget while at it. If you’re good at it, your store begins to grow. From receiving a couple orders a year, to getting one almost every day – if you don’t optimize the process of mailing orders out, it might just start taking a toll on you.

That is not to say that you should worry – it’s merely a matter of optimization, and, now you have a veritable resource to refer to. At Supercon 2023, [MakeItHackin]/[Andrew] has graced us with his extensive experience scaling up your sales and making your shipping process as seamless as it could be. His experience is multifaceted, and he’s working with entire four platforms – Tindie, Lectronz, Etsy and Shopify, which makes his talk all that more valuable.

[MakeItHackin] tells us how he started out selling hardware, how his stores grew, and what pushed him to automate the shipping process to a formidable extent. Not just that – he’s developed a codebase for making the shipping experience as smooth as possible, and he’s sharing it all with us.

His research was initially prompted by Tindie, specifically, striving to make the shipping process seamless. If you go the straightforward way and use the Web UI to copy-paste the shipping data in your postal system, it’s going to take you a good few minutes, and it’s an error-prone process. This is fine for a couple orders a year, but when you’re processing dozens of orders at a time, it starts to add up. Plus, there’s a few issues – for instance, the invoices Tindie prints out, are not customizeable. As for Etsy, it is less than equipped for handling shipping at all, and you are expected to have your own system.

There are APIs, however – which is where automation can begin. The goal is simple – spending as little time as possible on shipping, and as much time as possible on designing hardware. He shows us a video with a simple demo – cutting down the shipping label creation time from a couple minutes, down to fourteen seconds. That alone is a veritable result, and, there’s more.

On the way there, he’s had to reverse-engineer a couple APIs. In the talk, you get a primer about APIs – how they work, differences between external and internal APIs, ways to tap into internal APIs and make them work your magic. APIs are one of the keys to having the shipping process run smoothly and quickly, and [MakeItHackin] teaches you everything, from managing cookies to using browser inspect element tools and Selenium.

Another key is having fun. [MakeItHackin] gives us another demo – an automated system that stays in your workshop, powered by a Raspberry Pi and assisted by an Arduino, which does the entire process from start to finish without human input, save for actually putting things into envelopes and taking them to the post office. Of course, the system is also equipped with flashing lights and sirens – there’s no chance you will miss an order arriving.

Then, he goes into customs and inventory management. Customs forms might require special information added to the label, which is all that much easier to do in an automated process completely under your control. As for inventory management, the API situation is a bit dire, but he’s looking into a centralized inventory synchronization system for all four platforms too.

The last part is about working with your customers as people. Prompt and personalized communication helps – some might be tempted to use “AI” chatbots, and [MakeItHackin] has tried, showing you that there are specific limitations. Also, careful with the temptation to have part of your shipping process be cloud-managed – that also means you’re susceptible to personal data storage-related risks, so it might be best to stay away from it.

In the end, we get a list of things to watch out for. For instance, don’t use your personal details on the envelope, whether it’s the “From” address or the phone number, getting substitute ones is well worth it to protect your privacy. On the practical side, using a label printer might turn out to be significantly cheaper than using an inkjet printer – remember, ink costs money, and, there’s a dozen more pieces of advice that any up-and-coming seller ought to know.

Of course, all this is but a sliver of the wealth of information that [MakeItHackin] shares in his talk, and we are overjoyed to have hosted it. If you’re looking to start selling your hardware, or perhaps you’re well on your way, find 45 minutes for this talk – it’s worth its metaphorical weight in gold.