We’ve upped our video content game over the last couple of years and the steady stream of awesome is the reason so many people are subscribing. With this milestone reached, it’s a great time to look at the different styles of content Hackaday focuses on, and to get some feedback about what you would like to see on our channel!

Anyone following along with

We’ve upped our video content game over the last couple of years and the steady stream of awesome is the reason so many people are subscribing. With this milestone reached, it’s a great time to look at the different styles of content Hackaday focuses on, and to get some feedback about what you would like to see on our channel!

Anyone following along with the Hackaday Prize looks forward to regular updates from Majenta Strongheart. Her most recent installment covers robotics, and her power harvesting overview will hit the channel in about a week. Behind that camera and in the editing booth Jordon Clark really makes these updates look spectacular. Jordon has also been working on a lot of other content. He launched a series of the project features from Hackaday.io and makes the live streams from Hackaday meetups look and sound great! Here’s Christine Sunu’s Emotive Robotics talk from the Hackaday LA meetup in May.

Of course we continue to do videos on new product features and releases (the Arduino Vidor reveal at Maker Faire was a big hit), as well as tutorial videos like the latest guide on pad printing which Brian Benchoff published this week. This is also the channel where you’ll find all of our Hackaday conference coverage, from livestreams, to on-site interviews and the recordings of all the talks — here’s Rachel Wong’s keynote from Hackaday Belgrade.

Thank you to everyone who has been watching, and to all of the Hackaday crew who put incredible passion into producing fun, high quality videos. We’re always looking for ideas so please let us know in the comments, what would you like to see on Hackaday’s YouTube channel?

To be fair, this is not a craft you’d sail the high seas in, its unique hull design rendered in single-skin …read more

]]>To be fair, this is not a craft you’d sail the high seas in, its unique hull design rendered in single-skin plywood might have some stability issues and probably would have difficulty maintaining structural integrity in a high sea. But it’s perfect for their summer time backwater, with its electric outboard, steering wheel, and seat from a Russian saloon car.

The plans are fairly simple, cut from two sheets of ply it has an angular pointed front, sloping sides, and a fairly narrow bottom. Our experience with river boats would have led to a wider flat-bottomed hull, but this one looks stable enough for their purposes. Everything is held together with PVA glue and extra pieces of wood over the joints, something that amazingly keeps the water at bay. It is fairly obviously a rather basic and ever some might say rather ugly boat, but we’d guess there are few readers who wouldn’t want to give it a spin as part of a summer holiday.

If this has caught your fancy, don’t panic, the Northern Hemisphere still has some summer left, and all you need to do is find a plastic barrel!

Thanks [Keith Olson] for the tip!

]]>I don’t mean to toot our own horn, but humans are remarkable for having created numerous numeral systems, each specialized in their own ways. Ask almost anyone …read more

]]>I don’t mean to toot our own horn, but humans are remarkable for having created numerous numeral systems, each specialized in their own ways. Ask almost anyone and they will at least have heard of binary. Hackaday readers are deeper into counting systems and most of us have used binary, octal, and hexadecimal, often in conjunction, but those are just the perfectly standard positional systems.

If you want to start getting weird, there’s balanced ternary and negabinary, and we still haven’t even left the positional systems. There’s a whole host of systems out there, each with their own strengths and weaknesses. I happen to think seximal is the best. To see why, we have to explore the different creations that arose throughout the ages. As long as we’ve had sheep, humans have been trying to count them, and the systems that resulted have been quite creative, if inefficient.

Symbol | I | V | X | L | C | D | M |
---|---|---|---|---|---|---|---|

Value | 1 | 5 | 10 | 50 | 100 | 500 | 1,000 |

Way back when, somebody decided that tally marks just weren’t cutting it. From that frustration, the simple grouping system was born^{[1]}.

By definition, it’s simple. Pick any integer you like; call it b. Now, decide upon a symbol for the powers of b: `1, b, b²`

, and so on. Then any integer can be represented as a grouping of those symbols, simply adding them together. If you have a number that’s equal to `1 + 1 + 1 + b + b + b + b²`

and want to write it down, all that’s necessary is to drop the plus signs and smush the symbols together (`111bbbb²`

), making addition of any two numbers in your system extremely intuitive. You could even rearrange them if you liked. `b²bbb111`

represents the same number as you have to add them all together anyway.

A familiar — if somewhat irregular — example of such a system appears in the Roman numerals, which takes `b`

to be 10. If you want something a bit more regular, the ancient Egyptian numerals shown below, also taking b to be 10, fit the bill quite nicely.

Symbol | 𓏺 | 𓎆 | 𓍢 | 𓆼 | 𓂭 | 𓆐 | 𓁨 |
---|---|---|---|---|---|---|---|

Value | 1 | 10 | 100 | 1,000 | 10,000 | 100,000 | 1,000,000 |

Unfortunately, the drawbacks of such a system are immediately apparent. For one, to represent a big number you need a lot of symbols. Every power of `b`

requires you to dig up a new one. The Romans compounded this by adding another symbol for every half of a power of 10. Another big drawback is how inefficient the use of its many symbols is. 99 would require eighteen total characters in Egyptian numerals: ** 𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆**. In the Roman system, 99 (

`XCIX`

) would require four — but only if you subscribe to subtractive notation, which is a relatively modern invention. If you prefer your numerals a bit more old fashioned, 99 would be `LXXXXVIIII`

for a total of ten characters. Any way you slice it, the simple grouping system simply groups too many symbols.The multiplicative grouping system^{[1]} does away with some of these inefficiencies. By adding symbols for every positive integer less than the base number `b`

, it dodges the sheer amount needed to represent numbers like 99. To demonstrate, let’s roll our own (as the standard examples have a few too many symbols to easily photograph). Set `b`

to 10 for comparison’s sake. Then `9b9`

would represent 99 in our new system, shaving a character off the modern Roman system and a whole fifteen off the Egyptian one. Much like the simple grouping system, `99b`

could represent the same number, but you have to multiply `b`

by 9 before adding them all up.

Now we’re cooking! By sacrificing some of the intuition of addition and adding in symbols for all the integers less than `b`

, the multiplicative grouping system makes physically writing numbers a bit faster. In fact, because of this, it still sees use today in Chinese numerals, also with `b`

set to 10 (I’m sensing a pattern). Unfortunately, the system still suffers from the glut of symbols required to represent anything particularly large and unwieldy. Every extra power of `b`

adds another symbol. Thus something like 22222 in decimal would require a full nine characters in the Chinese system, nearly double the amount required in standard decimal.

To shrink the representation of numbers a bit more, you have to remove one of the advantages of the grouping systems. In both the previous systems, you don’t really have to care where the symbols are; as long as they are grouped correctly, everything works out. However, in the positional system, we replace the powers of the base number `b`

— also known as a radix in a positional system — with the position that they occupy.

For example, take the number `7b98b³`

in our multiplicative system with base 10. From what we learned of multiplicative systems, `7b98b³ = 7b + 9 + 8b³ = 8b³ + 7b + 9`

. If we remove the admittedly fun ability to shuffle the symbols around and fix the powers of `b`

in a descending order from right to left (the reverse works just as well), only `8b³ + 7b + 9`

remains, leaving something quite similar to our nifty equation in the picture when `n = 4`

. Stripping away the plus signs and spaces takes us back to the multiplicative system with `8b³7b9`

.

Continuing with that thought, what happens when we strip away the `b`

‘s themselves? Simply popping the symbols out of place, leaving `879`

, causes some confusion when considering the number `8b²7b9`

, which would also reduce to `879`

. To solve this problem, we strengthen our restriction. Now, any power of `b`

that is not used and is less than the whole number is treated as if it were multiplied by 0, allowing the equation to come into play. `8b³7b9`

is actually `8b³ + 0b² + 7b + 9`

, which then condenses to `8079`

after taking away everything but the integers less than `b`

. `8b²7b9`

comes out to `879`

, strictly different from `8b³7b9`

. Each integer, even the unseen 0 in `8b³7b9`

, becomes the respective coefficient in the equation. As each power of `b`

is fixed into a single spot and cannot move, popping them out now loses no information.

Surprisingly, this condition forces the positional system to require more characters to represent powers of `b`

than any of the previous systems. Instead of just one symbol, it takes `k + 1`

many, where `k`

is the exponent of the power of `b`

we’re trying to represent. However, by restricting the powers of `b`

to a certain position and requiring that they be represented at all times, the positional system does away with many of the inefficiencies of the past. Only `b`

unique symbols are needed at any time, which was the biggest disadvantage of the multiplicative system with its multitude. To write any integer requires only `n`

symbols, where `n`

is the exponent of the smallest power of `b`

greater than the integer, neatly stepping over the truly outrageous amount of symbols the value 99 required for representation in Egyptian numerals. Additionally, the invention of the decimal point and radix point in general allows the positional system to be easily extended to negative powers of `b`

, streamlining the use of fractions and greatly curbing the amount of symbols needed in the other systems.

Thus we arrive back into familiar territory. While the different numeral systems may have seemed to naturally arise out of each other, fighting over who can be the most efficient, they have co-existed at different times throughout history. Even now we have Roman numerals popping up at least every February. Each has its own strengths and weaknesses. Simple grouping systems make addition intuitive, but they’re gluttons for symbols. Multiplicative grouping systems sacrifice a bit of this intuition for a much more streamlined amount of characters per number. Positional systems remove the fun chaotic bits of the previous systems for a tiny number of symbols, requiring more characters to represent powers of `b`

in the process. If you go by how much information you need to decipher any given number in a certain system, positional systems smoked the rest, requiring only the positive integers less than b and the knowledge of where to place them. Clearly with the advent of decimal and binary, positional systems have come out the winner.

While they seem easily the most consistently efficient, positional systems also have the arguable position of most creative numeral system. The amount of bases you can use is literally uncountable as real numbers can be used for a radix. Our Hackaday members like to build computers based off balanced ternary. You can even mix up the bases if you really want. However, have you ever seen the number six? I present the seximal system.

Out of the integers come the rational numbers. Out of the rational numbers come the real numbers. Out of the real numbers come the complex numbers. Thus, how we represent our integers better be spiffy. This is where seximal comes in.

Seximal, or senary as it’s officially called, is the base-6 positional system, and it blows every other system out of the water. Six is of course a special number. It’s a perfect number: a sum of its proper divisors `1 + 2 + 3`

. It’s the first square-free composite number, being a product of no prime squared. It’s a *superior highly composite number*, meaning six has more divisors than any smaller positive integer and that this is significant even for its small size. Six is basically the bee’s knees of single digit numbers — in decimal at least.

Of course, Seximal has a lot more than just cool properties. Your seximal multiplication table has only 36 members and is thus easy to memorize. Compare to the 100 in decimal and 144 in duodecimal, and you start to see an argument for seximal through sheer laziness. Additionally, finger counting makes a lot more sense in seximal.

Counting on your hands in seximal, you can get up to 35 before you break out the toes. Sure, binary would let you get up to 1023, but you’ve got five fingers on each hand, naturally lending itself to seximal (count to five on one hand, each time you get to six that moves a digit on your other hand). As mentioned before, six has more divisors than any smaller positive integer, making division a breeze. The first prime it has any issues with is eleven. Everything else is mostly smooth sailing, as Conlang Critic mentions in his video along with dozens of other fun tidbits.

I won’t say that seximal is the most creative system out there. I won’t say that it’s the most efficient system out there. Both would be lies; however, I can guarantee that it would have kept the sheep counter awake. Every system has its purpose.

So, should we be reaching for the staples of zombie movies, and breaking out the long-playing records? Or should we be cautiously welcoming it back into the fold, a prodigal son to the wider family of boards? Before continuing, it’s best to take a closer look.

The C.H.I.P that …read more

]]>So, should we be reaching for the staples of zombie movies, and breaking out the long-playing records? Or should we be cautiously welcoming it back into the fold, a prodigal son to the wider family of boards? Before continuing, it’s best to take a closer look.

The C.H.I.P that has returned is a C.H.I.P Pro, the slightly more powerful upgraded model, and it has done so because unlike its sibling it was released under an open-source licence. Therefore this is a clone of the original, and it comes from an outfit called Source Parts, who have put their board up for sale via Amazon, but with what looks suspiciously like a photo of an original Next Thing Co board. We can’t raise Source Parts’ website as this is being written so we can’t tell you much about its originator and whether this is likely to be a reliable supplier that can provide continuity, so maybe we’d suggest a little caution until more information has emerged. We’re sure that community members will share their experiences.

It’s encouraging to see the C.H.I.P Pro return, but on balance we’d say that its price is not the most attractive given that the same money can buy you powerful boards that come with much better support. The SBC market has moved on since the original was a thing, and to make a splash this one will have to have some special sauce that we’re just not seeing. If they cloned the Pocket C.H.I.P all-in-one computer with keyboard and display, now that would catch our attention!

It all seemed so rosy for the C.H.I.P at launch, but even then its competitors doubted the $9 BoM, and boards such as the Raspberry Pi Zero took its market. The end came in March this year, but perhaps there might be more life in it yet.

Thanks [SlowBro] for the tip.

]]>It’s a bit counterintuitive that harder metals like steel are often easier to cut than softer metals; especially aluminum but also copper, nickel alloys, and some stainless steel alloys. But it happens, and [Srinivasan …read more

]]>It’s a bit counterintuitive that harder metals like steel are often easier to cut than softer metals; especially aluminum but also copper, nickel alloys, and some stainless steel alloys. But it happens, and [Srinivasan Chandrasekar] and his colleagues at Purdue University wanted to find out why, and what can be done about it. So the first job was to get up close and personal with the interface between a cutting tool and metal stock, to observe the dynamics of cutting. In a fascinating bit of video, they saw that softer metals tend to fold in sinuous patterns rather than breaking on defined shear planes.

Source: American Physical Society.

Having previously noted that cutting through Dykem, a common machinist’s marking fluid, changes chip formation in soft metals, the researchers tested everything from Sharpies to adhesive tape and even correction fluid, and found that they all helped to reduce the gumming action to some degree. Under their microscope they can clearly see that chips form differently once the cutting edge hits the treated surface, tending to act more brittle and ejecting rather than folding. They also noted a marked decrease in cutting force for the treated metal, and much-improved surface finish to boot.

Will Sharpies and glue sticks enter the book of old machinist’s tricks like gauge-block wringing? Only time will tell. But for now, this is a pretty fascinating bit of research that you might be able to put to the test in your shop. Let us know what you find in the comments.

[via Phys.org]

Thanks to [Qes], [Rob], and [Erin] for the near-simultaneous tips on this one.

]]>As a perfect example, take a look at this stupendously simple Internet-connected motion detector that [Eric William] has come up with. With just a Wemos …read more

]]>As a perfect example, take a look at this stupendously simple Internet-connected motion detector that [Eric William] has come up with. With just a Wemos D1 Mini, a standard PIR sensor, and some open source code, you can create a practical self-contained motion sensor module that can be placed anywhere you want to keep an eye on. When the sensor picks up something moving, it will trigger an IFTTT event.

It only takes three wires to get the electronics connected, but [Eric] has still gone ahead and provided a wiring diagram so there’s no confusion for young players. Add a 3D printed enclosure from Thingiverse and the hardware component of this project is done.

Using the Arduino Sketch [Eric] has written, you can easily plug in your Wi-Fi information and IFTTT key and trigger. All that’s left to do is put this IoT motion sensor to work by mounting it in the area to be monitored. Once the PIR sensor sees something moving, the ESP8266 will trigger IFTTT; what happens after that is up to you and your imagination. In the video after the break, you can see an example usage that pops up a notification on your mobile device to let you know something is afoot.

With its low cost and connectivity options, the ESP8266 is really the perfect platform for remote sensing applications. Though to give credit where credit’s due, this still isn’t the simplest motion sensor build we’ve seen.

]]>

The epoxies tested include Gorilla epoxy, Devcon Plastic Steel, …read more

]]>The epoxies tested include Gorilla epoxy, Devcon Plastic Steel, Loctite Epoxy Weld, JB Weld original, JB Weld Kwik Weld, and JB ExtremeHeat. This more or less covers the entire gamut of epoxies you would find in the glue aisle of your local home supply store; the Gorilla epoxy is your basic 5-minute epoxy that comes in a double barrel syringe, and the JB Welds are the cream of the crop.

The testing protocol for this experiment consisted of grinding a piece of steel clean, applying a liberal blob of each epoxy, and placing three bolts, head down, in each puddle. The first test was simply suspending weights in 2.5-pound increments to each bolt as a quick test of shear strength. Here, the losers in order were the JB Weld ExtremeHeat, JB Weld KwikWeld, Loctite, Gorilla Epoxy, Devcon Plastic Steel, and finally the JB Weld Original. Your suspicions are confirmed: those fancy new versions of JB Weld aren’t as good as the original. The fact that they’re worse than 5-minute epoxy is surprising, though. The second test — torquing the bolts out of the epoxy — gave similar results, with Devcon Plastic Steel beating the JB Weld Original *just barely*.

So, what do these results tell us? Cheap five-minute epoxy isn’t terrible, and actually better than the fancy new versions of JB Weld. Loctite is okay, and the Devcon and original JB Weld are at the top of their game. That’s not that surprising, as you can cast cylinder heads for engines out of JB Weld.

]]>