Freakishly Agile Crawler Rocks All-LEGO Mechanum Wheels

November 4, 2017 by 9 Comments

Mechanum wheels are great, but you have to have them perfectly alined or they come across a little clunky, giving your robot a herky-jerky movement. Robotics educator and supreme LEGO builder [Yoshihito Isogawa] built a mechanum-wheeled rover that has the angles right: each wheel consists of 12 smaller rubber tires angled at 45 degrees. The key to the project is Part Number 85940, accurately if unsexily named “double Ø4.85 hole w/ Ø3.2 shaft”. It consists of a double technic hole with a shaft projecting in a 45-degree angle.

Unlike his omni-roller project with 3 large wheels and the mechanum tank treads he built for another project, this one features the gold standard of mechanum movement: creepy agility. He also did a version with 9 side rollers per wheel, and it was nearly as stable.

Hackaday loves [Yoshihito]’s great creations, which are as beautiful and elegant as they are functional. His all-LEGO centrifugal pump and his spirograph machine make expert use of parts to make the builds as simple as possible.

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Sable-Machined Slingshot Is A Composite Marvel

November 4, 2017 by 9 Comments

Armed with an overseas CNC machine retrofitted with custom electronics, [Eric] has taken to wowing us with his suite of home-fabricated slingshots. In a more recent stint, he’s just polished off his Enzo Carbon Fiber Hydra Slingshot, complete with a build log that’s loaded with step-by-step insights.

[Eric’s] build started with a few carbon panels laying dormant in his shop for half a year. After epoxying two of these boards together for added thickness, he machines them down with his retrofitted Sable-2015 “Lunchbox CNC.” His final product accepts a few press-fit inserts, a few more machined ABS edge pieces for aesthetics, and behold: a professional slingshot that’s about as beautiful as it is dangerous.

Although the Sable-2015 CNC machine (made in Taiwan) isn’t a frequent flyer here on Hackaday, it had dozens of proud owners on a few hobby machinist forums that will rave about its wares. We’re proud to see a small-but-sturdy machine that we could carry one-handed be put to such delicate work.

[Eric] could’ve had us with his Lunchbox CNC Instructable, but he’s taken his craftsmanship to the next level by leveraging his homebrew tools and living the bootstrapped-machine-shop narrative. Slingshots don’t land here too often on these pages, but if you’re hungry for another machine monster, have a look at [Dennis the Menace’s] Triple Threat.

Circuit Challenge: Two Transistor 3.3V Regulator

November 4, 2017 by 26 Comments

[Kevin Darrah] wanted to make a simple 3.3V regulator without using an integrated circuit. He wound up using two common NPN transistors and 4 1K resistors. The circuit isn’t going to beat out a cheap linear regulator IC, but for the low component count, it is actually pretty good.

In all fairness, though, [Kevin] may have two transistors, but he’s only using one of them as a proper transistor. That one is a conventional pass regulator like you might find in any regulator circuit. The other transistor only has two connections. The design reverse biases the base-emitter junction which results in a roughly 8V breakdown voltage. Essentially, this transistor is being used as a poor-quality Zener diode.

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Printed Parts Make DIY Electric Longboard Possible

November 4, 2017 by 13 Comments

Appalled by expensive electric longboards, [Conor Patrick] still wanted one, and wanted it now. So — naturally — he converted an existing board into a sprightly electric version at a fraction of the cost.

[Patrick] is using a capable 380KV Propdrive motor, capable of pushing him up to 30mp/h! A waterproof 120A speed controller and 6000mAh, 22.2V LiPo battery slim enough to fit under the board give the motor the needed juice. He ended up buying the cheapest RF receiver and remote combo to control the board, but it fit the all-important “want electric long board now” criterion.

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Fridge Alarm Speaks, And Saves Power & Food

November 4, 2017 by 21 Comments

One of the most power-hungry devices in our homes, besides the air conditioner or heater, is our refrigerator and freezer. It’s especially so if the door doesn’t close all the way or the magnetic seal doesn’t seat properly. [Javier] took to solving a recurring problem with his personal fridge by attaching an alarm to the door to make sure that it doesn’t consume any more power than it absolutely needs.

At its core the device is straightforward. A micro switch powers a small microcontroller only when the door is open. If the door is open for too long, the microcontroller swings into action. The device then powers up a small wireless card (which looks like a variant of the very well-documented ESP module), that communicates with his microwave of all things, which in turn alerts him with an audible, spoken alarm that the refrigerator hasn’t closed all the way. It’s all powered with a battery that will eventually need to be recharged.

While there are certainly easier ways to implement an alarm, the use of the spoken alarm is a nice touch for this project, and the power savings that can be realized are not insignificant. There’s also the added benefit that [Javier] can prevent his freezer from frosting over. If you’re in the mood for other great fridge hacks, there are other exciting, novel, and surely one-of-a-kind ways to trick out your refrigerator.

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Inductive Loop Vehicle Detector Gets Modernized

November 4, 2017 by 41 Comments

Much like George Lucas and the original Star Wars films, many of us may find that our passion projects are never quite finished, especially when new technology comes around or we just want to make some improvements for their own sake. [Muris] was featured a while back for a vehicle detecting circuit, but is back with some important upgrades to his project. (Which, luckily, do not include any horrible CGI aliens.)

For starters, the entire project has been reworked from the ground up. For anyone unfamiliar with the original project, the circuit detected a vehicle via an inductive loop and was able to perform a task like opening a gate. It now has two independent channels which are polled separately, yet has a reduced parts count which should make construction simpler. The firmware has also been reprogrammed, and in addition to sensing a vehicle’s presence can now also measure the speed of any vehicles passing by.

The complete list of improvements can be found on the project page, and an extensive amount of documentation is available on this if you want to try to roll out your own inductive loop vehicle detector. Of course, this isn’t the only way to detect a vehicle’s presence if inductive loops aren’t really your style.

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386 Too Much Horsepower? Try A 186, In An FPGA!

November 3, 2017 by 45 Comments

Typically when we hear the term “System-on-Chip” bandied around, our mind jumps straight to modern ARM-based processors that drive smartphones and embedded devices around us. Coming a little bit more out of left field is [Jamie]’s 80186 core, that runs on Intel FPGAs.

[Jamie] ran the core through a few vintage PC benchmarks.
[Jamie] has implemented the entire set of 80186 instructions in Verilog, and included some of the undocumented instructions too. This sort of attention to detail is important – real world parts don’t always meet the original specifications on paper, and programmers can come to rely on this. The key to compatibility is understanding how things perform in the real world, not just on the spec sheet.

Not content to simply simulate a CPU, all the necessary peripherals for a complete working system have been worked into the design as well. There’s RAM, a UART, as well as CGA graphics and a PS/2 controller that is necessary if you’d like to actually use any sort of human input device.

[Jamie] has released the code under a GPL licence, and it’s available at GitHub. It’s a good basis if you want to play around with what was once a commercial CPU at a logic level. The development guide is also available if you need to really drill down into the details. It’s a cool project, and makes a great contrast to [Jamie]’s previous work – the Oldland 32-bit core.