Minature Table Saw Gets The Teeny Jobs Done

October 10, 2019 by 36 Comments

Table saws are highly useful tools, but tend to take up a lot of space. They’re usually designed to handle the bigger jobs in a workshop. It doesn’t have to be that way, however, as [KJDOT] demonstrates with a miniature table saw.

It’s a saw that relies on a simple build. The frame is made of plywood, and can be built with just a drill and a hand saw. A brushed motor is used to run the saw, using an off-the-shelf PWM controller and a 24V power supply. A handful of bearings and standard brackets are then used to put it all together, and there’s even a handy adjustable fence to boot. With a 60mm blade fitted, the saw is ready to go.

It’s a build that would be great for anyone regularly working with wood or plastics on the smaller scale. If you like building dollhouses, this could be the tool for you. You might also find the table nibbler to be an enticing proposition. Video after the break.

Continue reading “Minature Table Saw Gets The Teeny Jobs Done” →

The Next Generation Arduino Nano

October 10, 2019 by 40 Comments

While we certainly do love the Arduino Nano for its low-cost and versatility in projects, it’s unarguable that every tools has its gripes. For one maker in particular, there were enough complaints to merit a redesign of the entire board. While Arduino may or may not be interested in incorporating these changes into a redesign of the development board, there is certainly room for a new manufacturer to step in and improve some features.

[Kevin Timmerman] takes a look at lower-cost clones of the Nano made in China to highlight a few interesting key differences that make the clones – cheaper but still compatible with legacy systems – more attractive.

The PCB manufacturing for the Arduino Nano currently places components on both sides of the board, requiring two operations for solder paste, pick-and-place, and reflow. Naturally this increases costs, simply designing a two-layer PCB with components on top lowers the price of manufacturing.

Since the ATmega328PB was released, it has proven to be a better and cheaper MCU for manufacturing than the ATmega328P, the current MCU used by the Arduino Nano and clones. While the newer MCU is not backwards compatible like its predecessor, it has additional UART, GPIO, counters, and other features that allow users to take advantage of new libraries and peripherals.

Rather than featuring the typical voltage regulator used by Arduino boards (used to allow the board to be powered by a voltage source greater than 5V), a switching regulator allows for less energy loss but a higher component cost. A better solution than both of these would be to simply not have a voltage regulator. While this may be controversial, there are sufficient battery power sources for this design to work (4 cells of AA or AAA NiMh batteries or a mobile phone charger).

The Arduino Nano uses a bootloader for handling programming the MCU, which requires the USB to serial bridge to be disconnected from anything that could interfere with the programming. Thus, programs using the COM port on the computer must release the port, including the serial monitor. Rather than using the bootloader, ICSP (in-circuit serial programming) and DebugWire are possible alternatives that connect the ICSP pins to the CH551 development board or programming via the reset pin.

There are a number of other spec and firmware improvements suggested in the writeup, as well as comparison between the Arduino Nano, Arduino Every, and Chinese clones. It’s definitely worth a look!

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Tools, You Can’t Take Them With You

October 10, 2019 by 91 Comments

When I die I hope be buried in the English rural churchyard that has been my responsibility as churchwarden, after a funeral service that has been a celebration of my life. I am neither an Egyptian pharaoh nor a Viking queen though, so my grave will not contain all my tools and equipment to serve me in the afterlife. Instead aside from my mortal remains it will contain only a suitably biodegradable coffin, and my headstone will be a modest one bearing perhaps a technical puzzle to entertain visitors to the churchyard.

My workshop, my bench, and my tools will be the responsibility of my nearest and dearest, and I hope I will have suitably equipped them for the task of their dispersal. But for anyone who has a sizeable collection of gear, have you thought of what would happen if someone else had to clean it all out? What is profession for some and hobby for others, we deal in specialization that might as well be tools of arcane magic to the uninitiated.

Continue reading “Tools, You Can’t Take Them With You” →

DIY Tiny Dovetail Cube Needs DIY Dovetail Cutter

October 10, 2019 by 4 Comments
Dovetail cutter, made from a 5 mm drill rod.

There’s a trinket called a dovetail cube, and [mitxela] thought it would make a fine birthday present. As you can see from the image, he was successful in creating a tiny version out of aluminum and brass. That’s not to say there weren’t challenges in the process, and doing it [mitxela] style means:

  • Make it tiny! 15 mm sides ought to do it.
  • Don’t have a tiny dovetail bit on hand, so make that as well.
  • Of course, do it all without CNC in free-machining style.
  • Whoops the brass stock is smaller than expected, so find a clever solution.
  • That birthday? It’s tomorrow, by the way.

The project was a success, and a few small learning experiences presented themselves. One is that the shape of a dovetail plays tricks on the human eye. Geometrically speaking, the two halves are even but it seems as though one side is slightly larger than the other. [mitxela] says that if he were to do it again, he’d make the aluminum side slightly larger to compensate for this visual effect. Also, deburring with a knife edge on such a small piece flattened the edges ever so slightly, causing the fit to appear less precise than it actually is.

Still, it was a success and a learning experience. Need more evidence that [mitxela] thrives on challenge? Take a look at his incredible vector game console project.

What Will We Do With The Turbine Blades?

October 10, 2019 by 172 Comments

As the global climate emergency continues to loom over human civilization, feverish work is underway around the world to find technical and political solutions to the problem. Much has been gained in recent years, but as global emissions continue to increase, there remains much left to do to stave off the most catastrophic effects of climate change.

Renewable energy has led the charge, allowing humanity to continue to enjoy the wonders of electricity with a reduced environmental impact. The future looks promising, with renewable sources becoming cheaper than traditional fossil fuel energy plants in many cases, both in the US and abroad. At the same time, the rise of renewable technologies has brought new and varied challenges to the fore, which must be dealt with in kind. Take wind energy, for instance. Continue reading “What Will We Do With The Turbine Blades?” →

This Sentence‌‌‌‌‍‌ Isn’‌‌‌‌‍‌‬t Just ‌‌‌‌‌‬‌‌a‌‌‌‌‍‬‬‍ Sentence‌‌‌‌‍‌‌‌‌‌‌‬‌‌‌‌‌‌‍‬‬‍‌‌‌‌‍‍‌‌‌‌‌‌

October 10, 2019 by 22 Comments

Some sentences have more than meets the eye, and we’re not talking about interpretive nonsense. Rather, some sentences may contain up to four paragraphs’ worth of hidden text, invisible to readers.

Thanks to Zero Width Obfuscation, it is possible to use Zero Width Characters – Unicode characters that are invisible even when you try to highlight them. They’re typically used for abstract foreign languages that require separators that don’t take up an entire space. In this case, they’re used to obfuscate and de-obfuscate hidden messages sent through text.

[inzerosight] published a browser extension that identifies, de-obfuscates, and obfuscates these messages for you on the web. It does this by querying each page for the Unicode of the Zero Width Characters (U+FEFF, U+200C, U+200D, U+200E, U+2060, U+180E) and highlighting where they’ve been spotted. The encoding replaces each Unicode character with a permutation of two of the Zero Width Characters, essentially doing a find and replace across the text message.

I’m just waiting to see how long it takes for Zero Width Obfuscation to become the next Konami Code Easter Egg.

How Random Is Random?

October 10, 2019 by 10 Comments

Many languages feature a random number generator library for help with tasks like rolling a die or flipping a coin. Why, you may ask, is this necessary when humans are perfectly capable of randomly coming up with values?

[ex-punctis] was curious about the same quandary and decided to code up an experiment to test the true randomness of human. A script guesses the user’s next input from two choices, keeping a tally in the JavaScript backend that holds on to the past five choices. If the script guesses correctly, they take $1 from the user. Otherwise, the user earns $1.05.

The data from gathered from running the script with 200 pseudo-random inputs 100,000 times resulted in a distribution of correct guess approximately normal (µ=50% and σ=3.5%). The probability of the script correctly guessing the user’s input is >57% from calculating µ+2σ. The result? Humans aren’t so good at being random after all.

It’s almost intuitive why this happens. Finger presses tend to repeat certain patterns. The script already has a database of all possible combinations of five presses, with a counter for each combination. Every time a key is pressed, the latest five presses is updated and the counter increases for whichever combination of five presses this falls under. Based on this data, the script is able to make a prediction about the user’s next press.

In a follow-up statistic analysis, [ex-punctis] notes that with more key presses, the accuracy of the script tended to increase, with the exception of 1000+ key presses. The latter was thought to be due to the use of a psuedo random number generator to achieve such high levels of engagement with the script.

Some additional tests were done to see if holding shorter or longer sequences in memory would account for more accurate predictions. While shorter sequences should theoretically work, the risk of players keeping a tally of their own presses made it more likely for the longer sequences to reduce bias.

There’s a lot of literature on behavioral models and framing effects for similar games if you’re interested in implementing your own experiments and tricking your friends into giving you some cash.