Many bash scripts start out as something quick and dirty but then become so useful that they live for years, indeed sometimes seeing more use than our traditional programs. Now that you can even run bash well under Windows (although, you’ve always been able to run it there if you tried), there are even more opportunities for your five-minute bash script to proliferate. [Maciej] decided he was tired of always having to patch up his quick and dirty scripts to be more robust, so he created (and shared) his boilerplate template for scripts.
Probably most of us have at least some basic template we start with, even if it just our last script project. What’s nice about [Maciej’s] template is that he documents what’s going on with each part of it. It is also relatively short without a lot of excess stuff. Of course, you’ll probably customize it, but it is a great place to start.
The inlet and exhaust valve timing of a piston engine plays a large role in engine performance. Many modern automotive engines have some sort of variable valve timing, but the valves are still mechanically coupled together and to the crankshaft. This means that there is always a degree of performance compromise for various operating conditions. [Wesley Kagan] took inspiration from Koenigsegg’s camless Freevalve technology, and converted a Harbour Freight engine to camless technology for individual valve control.
By eliminating the traditional camshaft and giving each valve its actuator, it is possible to tune valve timing for any specific operating condition or even for each cylinder. A cheap single-cylinder engine is a perfect testbed for the garage hacker. [Wesley] removed the rocker arms and pushrods, and replaced the stock rocker cover with a 3D printed rocker cover which contains two small pneumatic pistons that push against the spring-loaded valve stems. These pistons are controlled by high-speed pneumatic solenoid valves. A reference timing signal is still required from the crankshaft, so [Wesley] built a timing system with a 3D printed timing wheel containing a bunch of embedded magnets and being sensed by a stationary Hall effect sensor. An Arduino is used to read the timing wheel position and output the control signals to the solenoid valves. With a rough timing program he was able to get the engine running, although it wouldn’t accelerate.
In the second video after the break, he makes a digital copy of the engine’s existing camshaft. Using two potentiometers in a 3D printed bracket, he measured push rod motion for a complete engine cycle. He still plans to add position sensing for each of the valves, and after a bit more work on the single-cylinder motor he plans to convert a full-size car, which we are looking forward to.
When we first laid eyes on Keybon, the adaptive macro keyboard, we sort of wondered what the big deal was. It honestly looked like any other USB macro keyboard, with big icons for various common tasks on the chunky keys. But looks can be deceiving, and [Max Kern] worked a couple of surprises into Keybon.
First of all, each one of Keybon’s buttons is actually a tiny OLED display, making the keycaps customizable through software. Each of the nine 0.66″ displays has a resolution of 64 x 48 pixels, which is plenty for all kinds of icons, and each is mounted over an SMD pushbutton switch. He had to deal with the problem of the keycaps just wobbling around atop the switch button without depressing it; this was solved with a 3D-printed cantilever frame that forced the keycaps to pivot only in one axis, resulting in clean, satisfyingly clicky keypresses.
The other trick that Keybon has is interactivity. By itself, it boots up with a standard set of icons and sends the corresponding keystrokes over USB. But when used with its companion Windows application, the entire macro set can be switched out to accommodate whatever application is being used. This gives the users access to custom macros for a web browser, EDA suite, CAD applications, or an IDE. The app supports up to eight macro sets and can be seen in action in the video below.
We love the look and the functionality [Max.K] has built into Keybon, but we wonder if e-ink displays would be a good choice for the keycaps too. They’re available for a song as decommissioned store shelf price tags now, and they might be nice since the icon would persist without power.
When you want to quickly pull together a combination of media and user interaction, looking to some building blocks for the heavy lifting can be a lifesaver. That’s the idea behind Max, a graphical programming language that’s gained a loyal following among anyone building art installations, technology demos (think children’s museum), and user Kiosks.
Guy Dupont gets us up to speed with a how to get started with Max workshop that was held during the 2020 Hackaday Remoticon. His crash course goes through the basics of the program, and provides a set of sixteen demos that you can play with to get your feet under you. As he puts it, if you need sound, video, images, buttons, knobs, sensors, and Internet data for both input and output, then Max is worth a look. Video of the workshop can be found below.
While some love to carve up mountain roads, and others relish the challenge of perfectly apexing every corner at the track, many crave a different challenge. Drag racing is a sport all about timing, finesse, and brute power. Like any other discipline in motorsport, to compete you’ll need a vehicle finely honed for the task at hand. Here’s how you go about getting started on your first quarter-mile monster.
It’s All About Power, Right?
It’s true that if you want to go faster, having more power on tap is a great way to do it. If that’s what you’re looking for, we’ve covered that topic in detail – for both the naturally aspirated and forced induction fans. However, anyone that’s been to the drag strip before will tell you that’s only part of the story. All of the power in the world isn’t worth jack if you can’t get it down to the ground. Even if you can, you’ve still got to keep your steering wheels planted if you intend to keep your nose out of the wall. So, if you want more power, consider the articles linked above. For everything else that’s important in drag racing, read on below.
When it comes to their more adult-oriented models, Lego really knocked it out of the park with their Saturn V rocket model. Within the constraints of the universe of Lego parts, the one-meter-tall model is incredibly detailed, and thousands of space fans eagerly snapped up the kit when it came out.
But a rocket without a launchpad is just a little sad, which is why [Mark Howe] came up with this animatronic Saturn V launch pad and gantry for his rocket model. The level of detail in the launchpad complements the features of the Saturn V model perfectly, and highlights just what it took to service the crew and the rocket once it was rolled out to the pad. As you can imagine, extensive use of 3D-printed parts was the key to getting the look just right, and to making parts that actually move.
When it’s time for a launch, the sway control arm and hammerhead crane swing out of the way under servo control as the Arduino embedded in the base plays authentic countdown audio. The crew catwalk swings away, the engines light, and the service arms swing back. Then for the pièce de résistance, the Saturn V begins rising slowly from the pad on five columns of flame. [Mark] uses a trio of steppers driving linear actuators to lift the model; the flame effect is cleverly provided by strings of WS2812s inside five clear plastic tubes. We have to say it took some guts to put the precious 1,969-piece model on a lift like that, but the effect was well worth the risk.
This new pen cost $12.50, which is about $180 today. For many people, the improved experience that the ballpoint promised over the fountain pen was well worth the price. You might laugh, but if you’ve ever used a fountain pen, you can understand the need for something more rugged and portable.
Ballpoint pens are everywhere these days, especially cheap ones. They’re so ubiquitous that we don’t have to carry one around or really think about them at all. Unless you’re into pens, you’ve probably never marveled at the sheer abundance of long-lasting, affordable, permanent writing instruments that are around today. Before the ballpoint, pens were a messy nuisance.
A Revolutionary Pen
A ballpoint, up close and personal. Image via Wikipedia
Fountain pens use gravity and capillary action to evenly feed ink from a cartridge or reservoir down into the metal nib. The nib is split in two tines and allows ink to flow forth when pressed against paper. It’s not that fountain pens are that delicate. It’s just that they’re only about one step above dipping a nib or a feather directly into ink.
There’s no denying that fountain pens are classy, but you’re playing with fire if you put one in your pocket. They can be a bit messy on a good day, and the cheap ones are prone to leaking ink. No matter how nice of a fountain pen you have, it has to be refilled fairly frequently, either by drawing ink up from a bottle into the pen’s bladder or inserting a new cartridge. And you’re better off using it as often as possible, since a dormant fountain pen will get clogged with dried ink.
Early ballpoint pens were modeled after fountain pens, aesthetically speaking. They had metal bodies and refillable reservoirs that only needed a top-up every couple of years, compared to once a week or so for fountain pens. Instead of a nib, ballpoints have a tiny ball bearing made of steel, brass, or tungsten carbide. These pens rely on gravity to bathe the ball in ink, which allows it to glide around in the socket like a tiny roll-on deodorant.
