Pac-Man Ghost Helps With Air Quality Sensing

October 21, 2024 by Bryan Cockfield 13 Comments

In the past, building construction methods generally didn’t worry much about air quality. There were enough gaps around windows, doors, siding, and flooring that a house could naturally “breathe” and do a decent enough job of making sure the occupants didn’t suffocate. Modern buildings, on the other hand, are extremely concerned with efficiency and go to great lengths to ensure that no air leaks in or out. This can be a problem for occupants though and generally requires some sort of mechanical ventilation, but to be on the safe side and keep an eye on it a CO2 sensor like this unique Pac-Man-inspired monitor can be helpful.

Although there are some ways to approximate indoor air quality with inexpensive sensors, [Tobias] decided on a dedicated CO2 sensor for accuracy and effectiveness, despite its relatively large cost of around $30. An ESP32 handles the data from the sensor and then outputs the results to an array of LEDs hidden inside a ghost modeled after the ones from the classic arcade game Pac-Man. There are 17 WS2812B LEDs in total installed on a custom PCB, with everything held together in the custom 3D printed ghost-shaped case. The LEDs change from green to red as the air quality gets worse, although a few preserve the ghost’s white eyes even as the colors change.

For anyone looking to recreate this project and keep an eye on their own air quality, [Tobias] has made everything from the code, the PCB, and the 3D printer files open source, and has used accessible hardware in the build as well. Although the CO2 sensors can indeed be pricey, there are a few less expensive ways of keeping an eye on indoor air quality. Some of these methods attempt to approximate CO2 levels indirectly, but current consensus is that there’s no real substitute for taking this measurement directly if that’s the metric targeted for your own air quality.

Open-Source, 3D Printed Trackpad

October 21, 2024 by Bryan Cockfield 22 Comments

Touchpads, or trackpads, have been around since the 1980s. Today, you can often find them in laptops and notebook computers as pointing devices. With no moving parts, a trackpad are easy to integrate into the body of a portable computer. they’re much smaller than the traditional mouse. Until the advent of multitouch and gestures over the past two decades, though, they were generally poor substitutes for an actual mouse. These days, trackpads have enough features that some users prefer them even on their desktop computers. If you’re that type of person and don’t want to shell out a big pile of money for an Apple, Logitech, or other off-the-shelf trackpad you can always build your own.

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Solve: An ESP32-Based Equation Solving Calculator

October 15, 2024 by Dave Rowntree 10 Comments

We’re suckers for good-looking old-school calculators, so this interesting numerical equation-solving calculator by [Peter Balch] caught our attention. Based around the ESP32-WROOM-32 module and an LCD, the build is quite straightforward from an electronics point of view, with the main work being on the software side of things.

A custom keyboard was constructed on Veroboard using a handful of tactile switches arranged in a charlieplexing array to minimize the number of IO pins consumed. For the display, an off-the-shelf 240×320 ILI9341-based module hooked up by SPI was used. A single lithium cell was used for the power supply, connected to a USB

You don’t need much to make a usable keyboard.

charger module, but you could just as easily substitute a 3 x AA battery box. The case was designed in DesignSpark mechanical and 3D printed. It’s unclear what keyboard version they settled on; there are options for one with keycaps and one without. Regardless, a 3D-printed frame sits atop the keyboard circuit, with the graphics printed on photo paper and a protective coversheet on top. Continue reading “Solve: An ESP32-Based Equation Solving Calculator” →

3D Printed Hydrofoil Goes From Model Scale To Human Scale With Flight Controller

October 6, 2024 by Danie Conradie 5 Comments

Hydrofoils have been around for several decades, but watching a craft slice through the water with almost no wake never get old. In the videos after the break, [rctestflight] showcases his ambitious project: transforming a standup paddleboard into a rideable hydrofoil with active stabilization.

Unlike conventional electric hydrofoil boards that depend on rider skill for balance, [rctestflight] aims to create a self-stabilizing system. He began by designing a small-scale model, complete with servo-controlled ailerons and elevators, dual motors for differential thrust, and a dRehmFlight flight controller. A pair of sonar sensors help the flight controller maintain constant height above the water. The wings are completely 3D printed, with integrated hinges for flight control surfaces slots for wiring and control components. It’s better suited for 3D printing than RC aircraft since it’s significantly less sensitive to weight, allowing for more structural reinforcement. The small scale tests were very successful and allowed [rctestflight] to determine that he didn’t need the vertical stabilizer and rudder.

The full-sized version features a scaled up wing, larger servos and motors attached to an 11-foot standup paddleboard — minus its rear end — mounted on commercially available e-foil booms. A foam battery box stores a hefty LiFePO4 battery, while the electronics from the smaller version are repurposed here. Despite only catching glimpses of this larger setup in action at the end of the video, it promises an excitingly smooth lake ride we would certainly like to experience.

We’ve seen several 3D printed hydrofoils around here, but this promised to be the largest successful attempt. Don’t fail us [Daniel].

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See The “Pause-and-Attach” Technique For 3D Printing In Action

October 5, 2024 by Donald Papp 7 Comments

[3DPrintBunny] is someone who continually explores new techniques and designs in 3D printing, and her latest is one she calls “pause-and-attach”, which she demonstrates by printing a vase design with elements of the design splayed out onto the print bed.

The splayed-out elements get peeled up and attached to the print during a pause.

At a key point, the print is paused and one peels up the extended bits, manually attaching them to sockets on the main body of the print. Then the print resumes and seals everything in. The result is something that appears to defy the usual 3D printer constraints, as you can see here.

Pausing a 3D print to insert hardware (like nuts or magnets) is one thing, but we can’t recall seeing anything quite like this approach. It’s a little bit reminiscent of printing foldable structures to avoid supports in that it prints all of its own self-connecting elements, but at the same time it’s very different.

We’ve seen [3DPrintBunny]’s innovative approaches before with intentional stringing used as a design element and like the rest of her work, it’s both highly visual and definitely it’s own thing. You can see the whole process in a video she posted to social media, embedded below.

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Building A 3D Printed Scanning Tunneling Microscope

September 30, 2024 by Dave Rowntree 12 Comments

YouTuber [MechnicalRedPanda] has recreated a DIY STM hack we covered about ten years ago, updating it to be primarily 3D-printed, using modern electronics, making it much more accessible to many folks. This simple STM setup utilises a piezoelectric actuator constructed by deliberately cutting a piezo speaker into four quadrants. With individual drive wires attached to the four quadrants. [MechPanda] (re)discovered that piezoelectric ceramic materials are not big fans of soldering heat. Still, in the absence of ultrasonic welding equipment, he did manage to get some wires to take to the surface using low-temperature solder paste.

As you can tell, you can only image conductive samples

A makeshift probe holder was glued on the rear side of the speaker actuator, which was intended to take a super sharp needle-like piece of tungsten wire. Putting the wire in tension and cutting at a sharp angle makes it possible with many attempts to get some usable points. Usable, in this instance, means sharp down the atomic level. The sample platform, actuator mount and all the connecting parts are 3D-printed with PA-CF. This is necessary to achieve enough mechanical stability with normal room temperature fluctuations. Three precision screws are used to level the two platforms in a typical kinematic mount structure, which looks like the only hard-to-source component. A geared stepper motor attached to the probe platform is set up to allow the probe to be carefully advanced towards the sample surface. Continue reading “Building A 3D Printed Scanning Tunneling Microscope” →

3D Printer Swaps Build Plates To Automate Print Jobs

September 30, 2024 by Donald Papp 17 Comments

[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. Continue reading “3D Printer Swaps Build Plates To Automate Print Jobs” →