A Gloriously Impractical Electromechanical Display

For this year’s office holiday party, [Gavan Fantom] wanted to do something really special. Coworkers were messing with LEDs to come up with displays and decorations, but they lack that old-school feel of mechanical displays. He wanted to create something that had retro look of moving elements, but didn’t want to just recreate the traditional flip mechanism we’ve all seen over and over.

The mechanism to drive a single “pixel”.

What [Gavan] came up with is breathtakingly impractical 8×8 display that sounds as cool as it looks. Each “pixel” in the display is a 3D printed screw mechanism rotated by a hobby servo. As the pixel is rotated in its case, it becomes progressively more visible to the observer. The opacity of the pixel can even be adjusted by varying the degree of rotation, allowing for rudimentary display of grayscale images.

Each element in the display is made up of seven 3D printed parts and two nails, which the mechanism slides on to move forward and backward. An 8×8 display needs 64 elements, which means the entire display needs 64 servos, 128 nails, and a whopping 448 3D-printed parts. Even with two printers attacking the production in parallel, the printing alone took over two weeks to complete.

The display is powered by a Raspberry Pi and three “Mini Maestro” controllers which can each handle 24 servos. [Gavan] found some sample code in Python to pass commands to the Maestro servo controllers, which he used as a template when writing his own software. The Python script opens image files, converts them to grayscale, and then maps the value of each pixel to rotation of the corresponding servo. He says the software is a little rough and that there’s still some calibration to be done, but we think the results are phenomenal so far.

Mechanical displays are a favorite of hackers, due in no small part to the awesome noises they make while in operation. While we’ve seen some very creative approaches to this type of display before, what [Gavan] has created here is certainly in a league of its own.

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Small Jet Engine Model From Students Who Think Big

We love to highlight great engineering student projects at Hackaday. We also love environment-sensing microcontrollers, 3D printing, and jet engines. The X-Plorer 1 by JetX Engineering checks all the boxes.

This engineering student exercise took its members through the development process of a jet engine. Starting from a set of requirements to meet, they designed their engine and analyzed it in software before embarking on physical model assembly. An engine monitoring system was developed in parallel and integrated into the model. These embedded sensors gave performance feedback, and armed with data the team iterated though ideas to improve their design. It’s a shame the X-Plorer 1 model had to stop short of actual combustion. The realities of 3D printed plastic meant airflow for the model came from external compressed air and not from burning fuel.

Also worth noting are the people behind this project. JetX Engineering describe themselves as an University of Glasgow student club for jet engine enthusiasts, but they act less like a casual gathering of friends and more like an aerospace engineering firm. The ability of this group to organize and execute on this project, including finding sponsors to fund it, are skills difficult to teach in a classroom and even more difficult to test with an exam.

After X-Plorer 1, the group has launched two new project teams X-Plorer 2 and Kronos. They are also working to expand to other universities with the ambition of launching competitions between student teams. That would be exciting and we wish them success.

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If 3D Printer, Then Custom Aluminum Extrusion Brackets

Aluminum extrusions are a boon for mechanical assemblies, but they require a stock of brackets and other hardware to be kept on hand. [mightynozzle] has decided to make things a little easier for prototyping and low-stress assemblies by creating a collection of 3D printable brackets for aluminum extrusions. 3D printing your own bracket hardware means faster prototyping, and if the assemblies don’t need the extra strength and rigidity of metal brackets you can just stick with the 3D printed versions.

The files are on Thingiverse, and include STL files of common brackets as well as an OpenSCAD script for customizing. Not familiar with OpenSCAD? No problem, we have a quick primer with examples.

This project showcases two things well. The first is that while brackets are not particularly expensive or hard to obtain, it can still be worth 3D printing them to reduce the overall amount of hardware one needs to keep on hand to make prototyping faster. The other is that 3D printing can shine when it comes to the creation of things like brackets: a few dimes’ worth of plastic can be turned into precise yet geometrically simple objects that would be a pain to make by other means. It certainly beats sitting on one’s hands waiting for parts to be delivered.

ESP8266 Home Monitor Is Stylishly Simplistic

It’s often said that “Less is More”, and we think that the chic ESP8266 environmental monitor posted by Thingiverse user [bkpsu] definitely fits the bill. Dubbed “Kube”, the device is a 3D printed white cube with an OLED display in the center, which [bkpsu] says was designed specifically for the approval of his wife. Weirdly, she didn’t like the look of bare PCBs on the wall.

Multiple Kubes allow for whole-house monitoring.

Inside, things are a little more complex. The Kube uses the NodeMCU development board, and a custom breakout that [bkpsu] designed to interface with the display and sensors. For temperature and humidity monitoring, the Kube is using the ever-popular DHT22, and [bkpsu] mentions that he has future plans for things like motion sensors and direct control of RGB LED strips. All the data collected by the Kube is piped into openHAB via MQTT.

On the very detailed Thingiverse page, [bkpsu] gives background information on his design goals for the project, tips for printing out a high-quality case, a parts list with Amazon links, and pinout information for getting it all wired up. The PCB is even available on OSH Park for those who want a Kube of their own.

Even with all the stick home monitoring and automation products on the market today, many hackers simply can’t bring themselves to buying a turn-key commercial product. But we think with the results hackers have been getting rolling their own solutions, they just might be on to something.

FatPiBoy: Respin Game Boy With A Pop-Out Controller

Have you ever found yourself wishing you had a clone of the Game Boy, except it was actually twice as wide, and instead of holding it in your hands you pop a tiny separate controller out of the middle and play it that way? No? Well, neither have we. But that didn’t stop [Christian Reinbacher] from designing and building exactly that, and by the looks of the finished product, we have to say he might be onto something.

To be fair, the charmingly-named FatPiBoy is not really meant to be played like the GameBoy of yesteryear. It’s more like a game console with built in display; you prop the console up on something, and then remove the controller from the system and play that way.

The controller itself is a commercial product, the 8bitdo Zero, but [Christian] based the rest of the system on parts intended for the Adafruit PiGRRL. For the battery, [Christian] used a 4,500 mAh pack that was originally from his Nexus 7 tablet; a tip to keep in mind next time you’re looking for a big and cheap lithium-ion battery.

[Christian] notes that the case design isn’t perfect. There’s currently no external access to the Pi’s USB ports, and the recess for the 8bitdo Zero could be a few millimeters deeper. Still, we think he did an excellent job finishing the case and giving it a professional look; the case and controller look like nearly a perfect match.

This isn’t the first time we’ve seen a Raspberry Pi put on a GameBoy costume, but the FatPiBoy does bring something new to the table with its removable controller. Of course, if you think the controller [Christian] selected for this build is a bit too small, you can always substitute your own

Gorgeous Engineering Inside Wheels Of A Robotic Trail Buddy

Robots are great in general, and [taylor] is currently working on something a bit unusual: a 3D printed explorer robot to autonomously follow outdoor trails, named Rover. Rover is still under development, and [taylor] recently completed the drive system and body designs, all shared via OnShape.

Rover has 3D printed 4.3:1 reduction planetary gearboxes embedded into each wheel, with off the shelf bearings and brushless motors. A Raspberry Pi sits in the driver’s seat, and the goal is to use a version of NVIDA’s TrailNet framework for GPS-free navigation of paths. As a result, [taylor] hopes to end up with a robotic “trail buddy” that can be made with off-the-shelf components and 3D printed parts.

Moving the motors and gearboxes into the wheels themselves makes for a very small main body to the robot, and it’s more than a bit strange to see the wheel spinning opposite to the wheel’s hub. Check out the video showcasing the latest development of the wheels, embedded below.

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