The convergence of mechanics and electronics in robotics brings with it a lot of challenges. Thanks to 3D printing and low cost components, it’s possible to quickly and easily experiment with a variety of robotics mechanism for various use cases. [Paul Gould] has been doing exactly this, and is giving us a taste of ten designs he will be open sourcing in the near future. Video after the break.
Three of the designs are capstan mechanisms, with different motors and layouts, tested for [Paul]’s latest quadruped robot. Capstan mechanisms are a few centuries old, and were originally used on sailing ships to give the required mechanical advantage to tension large sails and hoist cargo.
Two of the mechanisms employ GUS Simpson Drives, which use a combination of belts and a rolling joint. These were inspired by the LIMS2-AMBIDEX developed at the University of Korea. The ever-popular cycloidal gearbox also makes and appearance in the form of a high torque dual disk linked, two stage, NEMA17 driven gearbox.
[Paul] also built a room sized skycam-like claw robot for his daughter, suspended by four ball chain strings reeled in by four brushless motors with ESP32 powered motor controllers. We are looking forward to having a close look at these designs when [Paul] releases them, and to see how his quadruped robot will turn out.
There’s one certainty wherever schoolchildren come into contact with computers: the hardware will inevitably emerge worse for the encounter. The school laptops managed by [Neil Lambert] certainly suffered, losing keys and power supplies aplenty. Faced with a pile of broken machines, he came up with the X-PC, a stylish all-in-one desktop computer built around the innards of a laptop.
Inside a modern laptop there is surprisingly little in the way of parts, now that removable media drives are largely a thing of the past and once the battery has been removed from the equation. When the keyboard and trackpad are subtracted and replaced with USB equivalents the inner workings are reduced to a relatively compact motherboard and hard drive alongside the screen.
The screen is encased in a lasercut frame that also mounts the motherboard. It includes a lasercut cover that folds over the top in a living hinge to create an A-frame case that also holds the power supply. As an extra bonus the centre of the A provides handy storage for a keyboard.
A niche activity in console fandom is the shrinking of full-size consoles to smaller formats, taking what could once only be played on the family TV into portable formats that fit in the pocket. In a particularly impressive example of the art, [GmanModz] has made what he claims is the world’s smallest portable Nintendo 64. What makes it particularly noteworthy is that he’s done it not with an emulator or a custom PCB, instead there is a real Nintendo 64 motherboard in there having undergone a significant quantity of trimming.
The video below the break goes into detail on the state of the art in these mods, and shows how he has eschewed the latest tech and instead restricted himself to only using commercially available breakout PCBs and off the shelf modules. The N64 board trimmed down particularly aggressively, requiring a lot of fine magnet wire soldering for the various PCBs replacing the parts removed. The cartridge slot is brought out to the back of the board at a right angle, jutting out from the rear of the 3D printed case above a space for an 18650 cell and allowing an original game cartridge to be played. There is a microcontroller to facilitate a few compromises on lesser uses of the Nintendo control pads, but the result is a fully playable mini handheld console. He does admit that “The battery life sucks, it’s uncomfortable to hold […] But hey — it fits in my pocket. Does your N64?” We can’t fault him on that.
As electric skateboards kits and components become more commonly available, you really need to do something different to make your custom board stand out. [Emiel] [The Practical Engineer] has managed to do this by building a half-track skateboard. (Video, embedded below.)
Except for the front trucks, fasteners and bearings, all the mechanical components on the board were custom-made. The sturdy rear chassis and the track sections were machined from aluminum plate, and the wheels and track linkages were machined from POM/Delrin. The large carbon fiber deck and the polyurethane pads on the tracks were custom molded, which [Emiel] covered in detail in separate videos, also below. Two beefy brushless motors drive the tracks and are powered by LiPos in enclosed in the sheet metal electronics box. The final product looks very well-built and refined, especially considering most of the work happened in a tiny 2 m x 3 m workshop.
It looks like the board handles gravel paths well, but we would really like to see how it performs on soft surfaces like sand, where even off-road skateboards can struggle. It struggled a bit with low RPM torque, so a slight gearing change is in this board’s future.
Few things excite a Hackaday staff member more than a glowing LED, so it should be no surprise that combining them together into a matrix really gets us going. Make that matrix tiny, addressable, and chainable and you know it’ll be a hit at the virtual water cooler. We’ve seen [tinyledmatrix]’s work before but he’s back with the COPXIE, a pair of tiny addressable displays on one PCBA.
The sample boards seen at top are a particularly eye catching combination of OSH Park After Dark PCB and mysterious purple SMT LEDs that really explain the entire premise. Each PCBA holds two groups of discrete LEDs each arranged into a 5×7 display. There’s enough density here for a full Latin character set and simple icons and graphics, so there should be enough flexibility for all the NTP-synced desk clocks and train timetables a temporally obsessed hacker could want.
It seems as though we still can’t hit the ceiling on better control schemes for 3D Printers. Input Shaping is the latest technique to land on our radar, a form of resonance compensation that all but eliminates the ghosting (aka: vertical ringing) artifacts we see on the walls of printed parts. While the technique has been around for decades, only recently did [Dmitry Butyugin] both apply it to 3D printer control and merge their hard work into the open source firmware package Klipper. Once tuned, the results are simply astonishing–especially since this scheme can augment the print quality of even the most budget printer.
A Split A/B Test with and without Klipper’s Input Shaping feature courtesy of [@LukesLaboratory]Assuming your 3D printer isn’t infinitely stiff, when your nozzle moves from point to point or changes direction, it vibrates in response to having its speed altered. The result is that the nozzle wobbles along the ideal path it’s trying to track. The result is ghosting, an aesthetic blemish that looks like vertical waves on the sides of your printed part.
Input Shaping is a feed-forward controls technique for cancelling the mechanical vibrations that create ghosting. The idea is that, if we wanted to move the machine from point to point, we send it two impulses. The first impulse kicks the machine into moving and the second impulse follows up at a precise time to cancel the vibrations we would see when the machine comes to a stop. Albeit, moving any machine by sending it two impulses is pretty crude, so we take these impulses, adjust their amplitudes so that they sum to 1, and convolve them with a control input signal that we’d actually like to send it. The result is that the resonance cancellation part of the signal seamlessly “mixes” into the control input signal, and the machine moves from point to point with significantly less vibration at the end of the travel move. For more info on the maths behind this process, have a look at the first four pages of this paper from [Singh and Singhose].
The only hiccup is that you need to do some up-front system characterization of your 3D Printer running Klipper before you can take advantage of this technique. Thankfully the Klipper update comes with a set of step-by-step instructions for characterizing your machine up-front. After a couple test prints to measure the periodicity of your ringing, you can simply apply your measurement results to your config file, and you’re set.
Input Shaping is a prime example of “just wrap a computer around it!“–fixing hardware by characterizing and cancelling unwanted behaviors with software. If you’re hungry for more clever, characterized hardware control schemes, look no further than this Anti-Cogging algorithm for BLDC Motors. And for a video walkthrough of the Klipper implementation, have a look at [eddietheengineer]’s breakdown after the break.
Does your 3D Printer run Klipper? We’d love to see some of your Input Shaping results in the comments.
The AlphaSmart NEO and NEO2 are great little word processors for distraction-free writing anywhere you want to go, but they lack the backlight of the later Dana model. Well, [starboyk] has done what many thought impossible and added a backlight to a NEO2. Experience gained from a ton of console mods and repairs led to the question of whether the NEO2’s LCD is similar to a Game Boy’s.
[starboyk] started with a fresh NEO2 from ebay, then swapped out the reflective polarizer for a translucent polarizer and added a trio of LED backlights meant for the original Game Boy across the back of the screen. The best part is that the backlight has its own power switch and a brightness control pot. It sounds easy enough, but this mod is not for the faint of heart as it sounds like a really tight fit in the end. Apparently we only need 500 orders to get a custom backlight manufactured, but barring that does anyone know of a backlight that’s 157mm x 44mm?
You can always stick with the mod where you power the USB-A port and use a USB reading light like I did with my NEO.
