Building An Ultralight In A Basement Is Just So Beautiful To See

June 16, 2018 by Brian Benchoff 15 Comments

[Peter] is at it again. Not content with being one of the best RC confabulators on YouTube, and certainly not content with the first airplane he built in his basement, [Peter Sripol] is building another airplane in his basement.

The first airplane he built was documented on YouTube over a month and a half. It was an all-electric biplane, built from insulation foam covered in fiberglass, and powered by a pair of ludicrously oversized motors usually meant for large-scale RC aircraft. This was built under Part 103 regulations — an ultralight — which means there were in effect no regulations. Anyone could climb inside one of these without a license and fly it. The plane flew, but there were a few problems. It was too fast, and the battery life wasn’t really what [Peter] wanted.

Now [Peter] is onto his next adventure. Compared to the previous plane, this has a more simplified, traditional construction. It’s a high wing monoplane with an aluminum frame. There are two motors again, although he’s still in the process of finding lower kV motors. This plane should also fly slower, longer, something you really want in an ultralight.

As far as tools required for this build, it’s surprising how few are needed to put the plane together. Of course, there are a few excessively large pop rivet guns and there will be some extra special aviation-grade bolts, but the majority of this plane will be made out of standard aluminum, insulation foam, a bit of wood, and some fiberglass. Watching [Peter] churn out high-end fabrication with these simple parts is so satisfying. If you have a drill press with a cross slide vise, you too can build a plane in your basement.

This is shaping up to be a truly fantastic build. [Peter] has already proven that yes, he can indeed build an airplane in his basement. This time, though, he’s going to have a plane that will stay in the air for more than just a few minutes.

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Delta Printer Morphs Into CNC Flat Coil Winder

June 16, 2018 by Dan Maloney 21 Comments

Anyone who has ever wound a coil by hand has probably idly wondered “How do they do this with a machine?” at some point in the tedious process. That’s about when your attention wanders and the wire does what physics wants it to do, with the rat’s nest and cursing as a predictable result.

There’s got to be a better way, and [Russ Gries] is on his way to finding it with this proof-of-concept CNC flat coil winder. The video below is a brief overview of what came out of an intensive rapid prototyping session. [Russ] originally thought that moving the coil would be the way to go, but a friend put him onto the idea of using his delta-style 3D-printer to dispense the wire. An attachment somewhat like a drag knife was built, but with a wire feed tube and a metal roller to press the wire down onto an adhesive surface. The wire feed assembly went through a few design iterations before he discovered that a silicone cover was needed for the roller for the wire to properly track, and that the wire spool needed to be fed with as little friction as possible. Fusion 360’s CAM features were used to design the tool paths that describe the coils. It seems quite effective, and watching it lay down neat lines of magnet wire is pretty mesmerizing.

We’ve seen a couple of cylindrical coil winding rigs before, but it looks like this is the first flat coil winder we’ve featured. We can’t help but wonder about the applications. Wireless power transfer comes to mind, as do antennas and coils for RF applications. We also wonder if there are ways to use this to make printed circuit boards. Continue reading “Delta Printer Morphs Into CNC Flat Coil Winder” →

Move Over Aluminum: Cast Iron For The Home Foundry

June 15, 2018 by Dan Maloney 53 Comments

When it comes to choice of metals that can be melted in the home foundry, it’s a little like [Henry Ford]’s famous quip: you can melt any metal you want, as long as it’s aluminum. Not that there’s anything wrong with that; there’s a lot you can accomplish by casting aluminum. But imagine what you could accomplish by recycling cast iron instead.

It looks like [luckygen1001] knows a thing or two about slinging hot metal around. The video below shows a fairly expansive shop and some pretty unique tools he uses to recycle cast iron; we were especially impressed with the rig he uses to handle the glowing crucibles from a respectful distance. The cast iron comes from a cheap and abundant source: car disc brake rotors. Usually available free for the asking at the local brake shop, he scores them with an angle grinder and busts them into manageable chunks with a hammer before committing them to the flames. The furnace itself is quite a thing, running on a mixture of diesel and waste motor oil and sounding for all the world like a jet engine starting up. [luckygen1001] had to play with the melt, adding lumps of ferrosilicon alloy to get a cast iron with better machining properties than the original rotors. It’s an interesting lesson in metallurgy, as well as a graphic example of how not to make a flask for molding cast iron.

Cast iron from the home shop opens up a lot of possibilities. A homemade cast aluminum lathe is one thing, but one with cast iron parts would be even better. And if you use a lot of brake rotors for your homebrew cast iron lathe, it might require special handling.

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Blinging Up A Scope: Scale Your Divisions In Style

June 14, 2018 by Ben James 20 Comments

When a hacker owns an oscilloscope, it’s more than a possession. Weary nights are spent staring at the display, frantically twiddling the dials to coax out vital information. Over time, a bond is formed – and only the best will do for your scope. So why settle for the stock plastic dials when you could go for gold? Well in case you hadn’t noticed, we’re partial to a bit of over-engineering here at Hackaday, and [AvE] has upgraded his Rigol scope by adding metal knobs.

Employing his usual talent in the shop, [AvE] first turns the basic knob shapes from the stock, before drilling them and milling the outer texture pattern at an angle. Voilà: six custom knobs for 100% more torque and traction control. No matter how trivial the project, it’s always good to watch him at work. This [AvE] video doesn’t come with the usual fruity language warning; instead this build is set to the swelling tones of Beethoven. “Less Talk – More Action!” says the title, but we have to say that we miss his quips. That said, he still manages to deliver his signature humour through action alone.

For some slightly more functional oscilloscope upgrades, you can read about adding a hybrid touchscreen interface, or hacking a Rigol scope’s software to unlock greater bandwidth, storage depth and more.

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A Guide To Audio Amps For Radio Builders

June 11, 2018 by Dan Maloney 14 Comments

For hams who build their own radios, mastering the black art of radio frequency electronics is a necessary first step to getting on the air. But if voice transmissions are a goal, some level of mastery of the audio frequency side of the equation is needed as well. If your signal is clipped and distorted, the ham on the other side will have trouble hearing you, and if your receive audio is poor, good luck digging a weak signal out of the weeds.

Hams often give short shrift to the audio in their homebrew transceivers, and [Vasily Ivanenko] wants to change that with this comprehensive guide to audio amplifiers for the ham. He knows whereof he speaks; one of his other hobbies is jazz guitar and amplifiers, and it really shows in the variety of amps he discusses and the theory behind them. He describes a number of amps that perform well and are easy to build. Most of them are based on discrete transistors — many, many transistors — but he does provide some op amp designs and even a design for the venerable LM386, which he generally decries as the easy way out unless it’s optimized. He also goes into a great deal of detail on building AF oscillators and good filters with low harmonics for testing amps. We especially like the tip about using the FFT function of an oscilloscope and a signal generator to estimate total harmonic distortion.

The whole article is really worth a read, and applying some of these tips will help everyone do a better job designing audio amps, not just the hams. And if building amps from discrete transistors has you baffled, start with the basics: [Jenny]’s excellent Biasing That Transistor series.

[via Dangerous Prototypes]

Bike-Driven Scarf Knitter Is An Accessory To Warmth

June 11, 2018 by Kristina Panos 25 Comments

Despite all our technological achievements, humans still spend a lot of time waiting around for trains. Add a stiff winter breeze to the injury of commuting, and you’ve got a classic recipe for misery. [George Barratt-Jones] decided to inject some warmth into this scene by inviting people to knit a free scarf for themselves by riding a bike.

All a person has to do is ride the Cyclo-Knitter for five minutes and marvel at their handiwork. By the time the scarf is finished, they’ve cycled past being cold, and they have something to hold in the warmth. Cyclo-Knitter is essentially an Addi Express knitting machine being belt-driven by a stationary bike. Power is transferred from the bike through large, handmade wooden gears using old bike tire inner tubes as belts. [George] built a wooden tower to hold the machine and give the growing scarf a protected space to dangle.

We love the utility of this project as much as the joy it inspires in everyone who tries it. Check out their scarves and their reactions after the break. We haven’t seen people this happy to see something they weren’t expecting since that billboard that kills Zika mosquitoes.

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Rubber Duck Debugging The Digital Way

June 10, 2018 by Dan Maloney 16 Comments

Anyone who slings code for a living knows the feeling all too well: your code is running fine and dandy one minute, and the next minute is throwing exceptions. You’d swear on a stack of O’Reilly books that you didn’t change anything, but your program stubbornly refuses to agree. Stumped, you turn to the only one who understands you and pour your heart out to a little yellow rubber duck.

When it comes to debugging tools, this digital replacement for the duck on your desk might be even more helpful. Rubber duck decoding, where actually explaining aloud to an inanimate object how you think the code should run, really works. It’s basically a way to get you to see the mistake you made by explaining it to yourself; the duck or whatever – personally, I use a stuffed pig– is just along for the ride. [platisd] took the idea a step further and made his debugging buddy, which he dubs the “Dialectic Ball,” in the form of a Magic 8-Ball fortune teller. A 3D-printed shell has an ATtiny84, an accelerometer, and an LCD screen. To use it, you state your problem, shake it, and read the random suggestion that pops up. The list has some obvious suggestions, like adding diagnostic print statements or refactoring. Some tips are more personal, like talking to your local guru or getting a cup of coffee to get things going again. The list can be customized for your way of thinking. If nothing else, it’ll be a conversation piece on your desk.

If you’re more interested in prognostication than debugging, we have no shortage of Magic 8-Ball builds to choose from. Here’s one in a heart, one that fits in a business card, and even one that drops F-bombs.

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