britt morgan tubeHow does it work? When a monitor can’t attach directly to a VESA mount, this assembly attaches to the mount instead. The three arms extend around the edge of the monitor to grip it from the bottom and top. Some hex-head M5 bolts and nuts are all that are required to assemble the parts, and the top arm is adjustable to accommodate different sizes of monitor. As long as the screen size is between 17 and 27 inches diagonal, and the monitor thickness falls between 30 mm and 75 mm, it should fit.
[Chris Mullins] wanted to automate opening and closing the slats of mini blinds in his apartment, and came up with a system to do it as a fun project. Manually opening and closing the slats means twisting a rod. Seems straightforward to automate that, but as usual when having to work around something that already exists, making no permanent alterations, complications arose.
The blinds are only 1 inch wide, leaving little room for mounting any sort of hardware. While there is a lot of prior art when it comes to automating blinds, nothing he found actually fit the situation [Chris] had, so he rolled his own.
The rod that is normally twisted to control the blinds is removed, and the shaft of a stepper motor takes its place. [Chris]’ mounting solution is made to fit blinds with narrow 1 inch tracks (existing projects he found relied on 2 inch tracks) and the 3D printed mount is fully adjustable, so the 28BYJ stepper motor can be moved into exactly the right position. Speaking of the stepper motor, the 28BYJ motor is unipolar but the A4988 driver he wanted to use is for bipolar steppers only. Luckily, cutting a trace on the motor’s PCB is all it takes to turn a unipolar motor into bipolar.
To drive the motor and provide wireless functionality, the whole thing works with a Wemos D1 ESP8266, an A4988 stepper driver, and a buck converter. While it worked fine as a one-off on a perfboard, [Chris] used the project as an opportunity to learn how to make a PCB using KiCad; the PCB project is here on GitHub and the ESP8266 runs the ESPHome firmware. Be sure to check out the project page on his blog for all the details; [Chris] links to all the resources there, and covers everything from a bill of materials to walking through configuration of ESPHome with integration into the open-source Home Assistant?project.
Looking to control natural light but blinds aren’t your thing? Maybe consider automated curtains.
[Petar Crnjak]’s Faze4 is a open source robotic arm with 3D printable parts, inspired in part by the design of industrial robot arms. In particular, [Petar] aimed to hide wiring and cables inside the arm as much as possible, and the results look great! Just watch it move in the video below.
Cycloidal gearboxes have been showing up in robotic arm projects more and more, and Faze4 makes good use of them. Why cycloidal gears? They are readily 3D printed and offer low backlash, which makes them attractive for robotic applications. There’s no need to design cycloidal gears from scratch, either. [Petar] found this cycloidal gear generator in OnShape extremely useful when designing Faze4.
The project’s GitHub repository has all the design files, as well as some video demonstrations and a link to assembly documentation for anyone who would like to make their own. Watch Faze4 go through some test movements in the video embedded below.
Typically, when we think of 3D printed parts, we think of unique parts with complex geometries that would be hard to fabricate with other techniques. Strength is rarely the first thing that comes to mind, due to the limitations of thermoplastics and the problem of delamination between layers. However, with smart design, it’s possible to print parts capable of great feats, just as [Brian]’s high-torque gearbox demonstrates.
The gearbox consists of entirely 3D-printed gears, along with the enclosure, with the only metal parts being a few bearings and shafts. Capable of being produced out of PLA on a regular FDM printer, [Brian] has successfully tested the gearbox up to 132 kg?cm. The suspicion is that there may be more left in it, but some slippage was noticed in the gear train when trying to tow a Ford Focus with the handbrake still on.
Even better, with the addition of a potentiometer, the gearbox can be used as an incredibly tough servo. [Brian] demonstrates this by lifting 22 kg at a distance of 6 cm from the center of the output shaft. The servo does it with ease, though eventually falls off the bench due to not being held down properly.
It’s a build that shows it’s possible to use 3D-printed parts to do some decently heavy work in the real world, as long as you design appropriately. [Brian] does a great job of explaining what’s involved, discussing gear profile selection and other design choices that affect the final performance. We’ve seen similar work from others before, too. Video after the break.
[jcprintnplay] has challenged himself to making Raspberry Pi cases in different ways, and his Fold-a-Pi enclosure tries for a “less is more” approach while also leveraging the strong points of 3D printing. The enclosure prints as a single piece in about 3 hours, and requires no additional hardware whatsoever.
The design requires no screws or other fasteners, and provides a mounting hole for a fan as well as some holes for mounting the enclosure itself to something. All the ports and headers are accessible, and the folding one-piece design is not just a gimmick; in a workshop situation where the Pi needs to be switched out or handled a lot, it takes no time at all to pop the Raspberry Pi in and out of the enclosure.
[James] points out that the trick with a print-in-place hinge like this is leaving enough space between the parts so that the two pieces aren’t fused together, but not so much space that the print fails. He doesn’t go into detail about how much space worked or didn’t work, but an examination of the downloadable model shows that the clearance used looks like 0.30 mm, intended to be printed with a 0.4 mm nozzle.
[James] also demonstrates the value of being able to do quick iterations on a design when prototyping. In a video (embedded below) The first prototype had the hinge not quite right. In the second prototype there was a lack of clearance when closing. The third one solved both and shows the final design.
Time may bring change, but kinematic couplings don’t. This handy kinematic couplings resource by [nickw] was for a design contest a few years ago, but what’s great is that it includes ready-to-use models intended for 3D printing, complete with a bill of materials (and McMaster-Carr part numbers) for hardware. The short document is well written and illustrated with assembly diagrams and concise, practical theory. The accompanying 3D models are ready to be copied and pasted anywhere one might find them useful.
What are kinematic couplings? They are a way to ensure that two parts physically connect, detach, and re-connect in a precise and repeatable way. The download has ready-to-use designs for both a Kelvin and Maxwell system kinematic coupling, and a more advanced design for an optomechanical mount like one would find in a laser system.
The download from Pinshape requires a free account, but the models and document are licensed under CC – Attribution and ready to use in designs (so long as the attribution part of the license is satisfied, of course.) Embedded below is a short video demonstrating the coupling using the Maxwell system. The Kelvin system is similar.
The variety of ways that people find to show the passage of time never ceases to amaze us. Just when you think you’ve seen them all, someone comes up with something new and unusual, like the concentric rings of this automated perpetual calendar.
What we really like about the design that [tomatoskins] came up with is both its simplicity and its mystery. By hiding the mechanism, which is just a 3D-printed internal ring gear attached to the back of each ring, it invites people in to check it out closely and discover more. Doing so reveals that each ring is hanging from a pinion gear on a small stepper motor, which rotates it to the right point once a day or once a month. Most of the clock is made from wood, with the rings themselves made using the same technique that woodturners use to create blanks for turning bowls — or a Death Star. We love the look the method yields, although it could be even cooler with contrasting colors and grains for each segment. And there’s nothing stopping someone from reproducing this with laser-cut parts, or adding rings to display the time too.
Another nice tip in this write up is the trick [tomatoskins] used to label the rings, by transferring laser-printed characters from paper to wood using nothing but water-based polyurethane wood finish. That’s one to file away for another day.