Big Workshop Clock Is 3D Printing Done Right

November 1, 2020 by Lewin Day 7 Comments

Time is something uniquely important to humans, and they remain the only creatures on the planet to build devices to regularly track its progress. [Ivan Miranda] is one such creature, and built a giant 7-segment clock for his workshop that really ties the room together.

The clock is a testament to [Ivan]’s design skills in the 3D printed space. Taking advantage of his large format printer, each segment consists of a front panel, large single-piece diffuser, LED carrier, and backing plate. There are plenty of nice touches, from the interlocking ridges between each digit, to integral printed arrows on the inside that guide installation of the LED strips. Fit and finish approaches the level of a commercial product, a reward for [Ivan]’s years of practice in the field.

Electronically, an ESP8266 runs the show, synchronizing the time over its in-built WiFi connection. Each segment contains 9 WS2812B LEDs, wired up in a single long strip that’s addressed by the microcontroller. This means that the segments can be lit up to any color of the rainbow, though [Ivan] is a man who best appreciates the look of classic red.

[Ivan]’s long been a proponent of big 3D-printed builds — his tank-tracked electric skateboard is a particularly good example. Video after the break.

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Complete Flight Sim Controller Set With 3D Printing And Hall-Effect Sensors.

October 26, 2020 by Danie Conradie 17 Comments

[Tom Stanton] has been playing Microsoft Flight Simulator a lot recently, and decided his old desktop joystick needed an upgrade. Instead of just replacing it with a newer commercial model, he built a complete controller system with a long joystick that pivots at floor level, integrated rudder pedals and a throttle box. You can see it in action after the break.

The throw of the joystick is limited by [Tom]’s legs and chair, with only 12° of travel in either axis, which is too small to allow for high resolution with a potentiometer. Instead, he used hall effect sensors and a square magnet for each axis, which gives good resolution over a small throw angle. The pivot that couples the two rudder pedals also makes use of a hall effect sensor, but needs more travel. To increase the size of the magnetic field, [Tom] mounted two magnets on either side of the sensor with their poles aligned. To center the rudder pedals and joystick, a couple of long tension springs were added.

The joystick (left) and rudder pedals (right) magnet configurations with a hall effect sensor.

A normal potentiometer was used in the throttle lever, and [Tom] also added a number of additional toggle switches and buttons for custom functions. The frame of the system is built with T-slot extrusions, so components can quickly moved to fit a specific user, and adjust the preload on the centering springs. All the electronic components are wired to an Arduino Micro, and thanks to a joystick library, the code is very simple.

At a total build cost of £212/$275 it’s certainly not what anyone would call cheap, but it’s less than what you’d pay for a commercial offering. All the design files and build details are linked in the second video if you want to build your own.

The flight sim controller builds are coming in thick and fast with the release of the latest MS Flight Simulator. With 3D printing you can augment an Xbox controller with a joystick and throttle, or just use tape and a few electronic components turn a desk drawer into a flight yoke.

A Linear Stencil Clock Built For Quiet Operation

October 22, 2020 by Dan Maloney 19 Comments

We around the Hackaday shop never get tired of seeing new ways to mark the passage of time. Hackers come up with all manner of interesting timekeeping modalities using every imaginable material and method of moving the mechanism once per whatever minimum time unit the hacker chooses to mark.

But honestly, there are only so many ways to make a clock, and while we’re bound to see some repeats, it’s still nice to go over old ground with a fresh approach. Take this linear sliding stencil clock for instance. [Luuk Esselbrugge] has included some cool design elements that bear a closer look. The video below shows that the display is made up of four separate stepper motors, each driving a vertical stencil via a rack-and-pinion mechanism. There a simple microswitch for homing the display, and a Neopixel for lighting things up.

The video below shows that the stencils move very, very slowly; [Luuk] says that this is to keep the steppers as quiet as possible. Still, this means that some time changes take more than a minute to accomplish, which is a minor problem. The Neopixel also doesn’t quite light up just one digit, which should be a pretty easy fix for version 2. Still, even with these issues, we like the stately movements of this clock, and appreciate [Luuk]’s attempts to make it easier to live with.

Don’t let the number of clocks you see on these pages dissuade you from trying something new, or from putting your twist on an old design. Start with fridge magnets, an old oscilloscope, or even a bevy of steel balls, and let your imagination run wild. Just make sure to tell us all about it when you’re done.

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PyBot Is A 3D Printed SCARA Arm For The Masses

October 19, 2020 by Tom Nardi 10 Comments

We’ve all seen videos of blisteringly fast SCARA arms working on assembly lines, and more than a few of us have fantasied about having that same kind of technology for the home shop. Unfortunately, while the prices for things like 3D printers and oscilloscopes have dropped lower than what many would have believed possible a decade ago, high-performance robotics are still too pricey for the home player.

Unless of course, you’re willing to build it yourself. The PyBot designed by [jjRobots] is an open source robotic arm that should be well within the means of the average hardware hacker. One could argue that this is a project made entirely possible by desktop 3D printing; as not only are most of the structural components printed, but most of the mechanical elements are common 3D printer parts. Smooth rods, linear bearings, lead screws, and NEMA 17 motors are all exceptionally cheap these days thanks to the innumerable 3D printer kits that make use of them.

A custom control board keeps the wiring tight.

Those who’ve researched similar projects might notice that the design of this arm has clearly been influenced by the Mostly Printed SCARA (MPSCARA). But while that robot was designed to carry an extruder and act as a 3D printer, [jjRobots] intends for the PyBot to be more of a general purpose platform. By default it features a simple gripper, but that can easily be changed out for whatever tool or gadget you have in mind.

In the base of the arm is a custom control board that combines an Arduino M0, an ESP8266, and a trio of stepper motor drivers. But if you wanted to build your own version from the parts bin, you could certainly wire up all the principle components manually. As the name implies, the PyBot is controlled by Python tools running on the computer, so it should be relatively easy to get this capable arm to do your bidding.

We’ve seen some impressive 3D printed robotic arms over the years, but the simplicity of the PyBot is particularly compelling. This looks like something that you could reasonably assemble and program over a weekend or two, and then put to work in your ad-hoc PPE factory.

Adding Crush Ribs To 3D Printed Parts For A Better Press Fit

October 15, 2020 by Donald Papp 18 Comments

[Dan Royer] shared a tip about how to get a reliably tight fit between 3D printed parts and other hardware (like bearings, for example.) He suggests using crush ribs, a tried-and-true solution borrowed from the world of injection molding and repurposed with 3D printing in mind. Before we explain the solution, let’s first look at the problem a little more closely.

Imagine one wishes to press-fit a bearing into a hole. If that hole isn’t just the right size, the bearing won’t be held snugly. If the hole is a little too big, the bearing is loose. Too small, and the bearing won’t fit at all. Since a 0.1 mm difference can have a noticeable effect on how loose or snug a fit is, it’s important to get it right.

Crush rib locations highlighted with blue arrows.

For a 3D printed object, a hole designed with a diameter of 20 mm (for example) will come out slightly different when printed. The usual way around this is to adjust printer settings or modify the object until the magic combination that yields exactly the right outcome is found, also known as the Goldilocks approach. However, this means the 3D model only comes out right on a specific printer, which is a problem for a design that is meant to be shared. Since [Dan] works on robots with 3D printed elements, finding a solution to this problem was particularly important.

The solution he borrowed from the world of injection molding is to use crush ribs, which can be thought of as a set of very small standoffs that deform as a part is press-fit into them. Instead of a piece of hardware making contact with the entire inside surface of a hole, it makes contact only with the crush ribs. Press fitting a part into crush ribs is far easier (and more forgiving) than trying to get the entire mating surface exactly right.

Using crush ribs in this way is a bit of a hack since their original purpose in injection molding is somewhat different. Walls in injection-molded parts are rarely truly flat, because that makes them harder to eject from a mold. Surfaces therefore have a slight cant to them, which is called a draft. This slight angle means that press fitting parts becomes a problem, because any injection-molded hole will have slanted sides. The solution is crush ribs, which — unlike the walls — are modeled straight. The ribs are small enough that they don’t have an issue with sticking in the mold, and provide the mating surface that a press-fit piece of hardware requires. [Dan] has a short video about applying this technique to 3D printed objects, embedded below.

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A Smart Speaker That Reminds You It’s Listening

October 15, 2020 by Matthew Carlson 20 Comments

[markw2k9] has an Alexa device that sits in his kitchen and decided it was time to spruce it up with some rather uncanny eyes. With some inspiration from the Adafruit Uncanny Eyes project, which displays similar animated eyes, [markw2k9] designed a 3d printed shell that goes on top of a 2nd generation Amazon Echo. A teensy 3.2 powers two OLED displays and monitors the light ring to know when to turn the lights on and show that your smart speaker is listening. The eyes look around in a shifty sort of manner. Light from the echo’s LED ring is diffused through a piece of plexiglass that was lightly sanded on the outside ring and the eye lenses are 30mm cabochons (a glass lens often used for jewelry).

One hiccup is that the ring on the Echo will glow in a steady pattern when there’s a notification. As this would cause the OLEDs to be on almost continuously and concerned for the lifetime of the OLED panels, the decision was made to detect this condition in the state machine and go into a timeout state. With that issue solved, the whole thing came together nicely. Where this project really shines is the design and execution. The case is sleek PLA and the whole thing looks professional.

We’ve seen a few other projects inspired by the animated eyes project such as this Halloween themed robot that is honestly quite terrifying. The software and STL files for the smart speaker’s eyes are on Github and Thingiverse.

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Spin The Video Track With A Mechanical Flair

October 12, 2020 by Matthew Carlson 16 Comments

One of the most difficult user interfaces to get right is video editing. It is complex and fiddly with large amounts of precision required even after four or five hours of straight editing. Seeking to bring some of that interface out into the real world, [Zack Freedman] built a mechanical video editing keyboard.

The keyboard in question features popular shortcuts and keys to breeze through different parts of editing. The biggest feature is, of course, the large scrubbing knob, allowing [Zack] to fly through long video with precision. We’ve seen our fair share of mechanical keyboards that aren’t traditional keyboards on Hackaday before, such as this number pad or this macro pad.

One of the unique constraints of this project was the fact that Zack had a deadline of two days. This self-imposed deadline was to help focus the work and drive it towards completion. This meant that it had to be designed in such a way that roadblocks or troublesome features could be designed around or cut out altogether. At its heart, this project is just 14 mechanical switches, 4 potentiometers, and a Teensy to drive it all. It is the design, prototyping, and thought that went into this project that makes it noteworthy. There are plenty of lessons here about how to manage a project’s timeline and advice about how to actually finish it.

Code, STL’s, diagrams, and instructions are all on his GitHub.

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