Agate Light Twinkles Just Right

Mother Nature is often a cruel mistress, but what can you do? You’ve got to make the best of what she gives you. This lovely little light was born from death — the death of a pine tree, that is, that was killed by beetles boring large holes inside.

When [Craig Lindley]’s friends gave him some slices of that pine tree, he knew he had to make a blinkenlights thing out of it. The next step was to procure slices of agate, and from the top of Pike’s Peak, no less.

Each slice of agate has three RGB LEDs behind it, and  these are controlled by an ESP32. There’s also a PIR sensor that detects people and gives them a show. More specifically, it runs through several patterns at random speeds up and down the piece.

The agate slices are embedded in the wood, which [Craig] achieved first with a Dremel, and then with a router when the Dremel proved difficult. After some troubles with resin and an unfortunate mishap with a rag, [Craig] ended up with a beautiful light with which to dazzle his friends, especially the ones who gave him the pine slice.

You know we love blinkenlights; you see them here all the time. Did you know you can use them to keep time?

Exploring Woodworking Mysteries With Strain Gauges And Raspberry Pi

If you’re not a woodworker, you might not have heard of the “45-degree rule.” It goes like this: a clamp exerts a force that radiates out across a triangular region of the wood that forms a right angle — 45 degrees on each side of the clamp’s point of contact. So, to ensure that force is applied as evenly as possible across the entire glue joint, clamps should be spaced so that these force triangles overlap. It’s a handy rule, especially for the woodworker looking to justify the purchase of more clamps; you can never have too many clamps. But is it valid?

Myth busted?

The short answer that [ari kardasis] comes up with in the video below is… sort of. With the help of a wonderfully complex array of strain gauges and a Raspberry Pi, he found that the story isn’t so simple. Each strain gauge lives in a 3D printed bracket that spaces the sensors evenly along the wood under test, with a lot of work going into making the test setup as stiff as possible with steel reinforcement. There were some problems with a few strain gauges, but once he sorted that out, the test setup went into action.

[ari] tested clamping force transmission through pieces of wood of various widths, using both hardwoods and softwoods. In general, he found that the force pattern is much broader than the 45-degree rule suggests — he got over 60 degrees in some cases. Softwoods seemed to have a somewhat more acute pattern than hardwoods, but still greater than the rulebook says. At the end of the day, it seems like clamp spacing of two board widths will suffice for hardwoods, while 1.5 or so will do for softwoods. Either way, that means fewer clamps are needed.

A lot of woodworking is seat-of-the-pants stuff, so it’s nice to see a more rigorous analysis like this. It reminds us a lot of some of the experiments [Matthia Wandel] has done, like load testing various types of woods and glues.

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Pine Made Phones, Laptops, And Now… Soldering Irons?

The TS100 smart soldering iron may have some new competition. Pine — the people best known for Linux-based phones and laptops — though the world needed another smart soldering iron so they announced the Pinecil — Sort of a knock off of the TS100. It looks like a TS100 and uses the same tips. But it does have some important differences.

It used to be a soldering iron was a pretty simple affair. Plug in one end; don’t touch the other end. But, eventually, things got more complicated and you wanted some way to make it hotter or cooler. Then you wanted the exact temperature with a PID controller. However, until recently, you didn’t care how much processing power your soldering iron had. The TS100 changed that. The smart and portable iron was a game-changer and people not only used it for soldering, but also wrote software to make it do other things. One difference is that the device has a RISC-V CPU. Reportedly, it also has better ergonomics and a USB C connector that allows for UART, I2C, SPI, and USB connections. It also has a very friendly price tag of $24.99.

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Wood And Carbon Rods Used For This Handsome And Effective Microphone

Anyone who was active in the phreaking scene or was even the least bit curious about the phone system back in the Ma Bell days no doubt remembers the carbon capsule microphone in the mouthpiece of many telephone handsets. With carbon granules sandwiched between a diaphragm and a metal plate, they were essentially sound-driven variable resistors, and they worked well enough to be the standard microphone for telephony for decades.

In an attempt to reduce complicated practices to their fundamentals, [Simplifier] has undertaken this surprisingly high-fidelity carbon microphone build that hearkens back to the early days of the telephone. It builds on previous work that was more proof of concept but still impressive. In both builds, the diaphragm of the microphone is a thin piece of wood, at first carved from a single block of softwood, then later improved by attaching a thin piece of pine to a red oak frame. The electrical side of the mic has four carbon rods running from the frame to the center of the diaphragm, where they articulate in a carbon block with small divots dug into it. As the diaphragm vibrates, the block exerts more or less pressure on the rods, varying the current across the mic and reproducing the sound. It works quite well, judging by the video after the break.

Congratulations to [Simplifier] for another great build and top-notch craftsmanship. We’ve seen homebrew vacuum tubes, conductive glass, and solar cells from him before, which sort of makes him the high-tech version of Primitive Technology. We’re looking forward to whatever comes next. Continue reading “Wood And Carbon Rods Used For This Handsome And Effective Microphone”

Hands On With The Pinebook

The Pine A64 was a 64-bit Quad-Core Single Board Computer which was kickstarted at the tail end of 2015 for delivery in the middle of 2016. Costing just $15, and hailed as a “Raspberry Pi killer,” the board raised $1.7 million from 36,000 backers. It shipped to its backers to almost universally poor reviews.

Now they’re back, this time with a laptop—a 11.6-inch model for $89, or a 14-inch model for $99. Both are powered by the same 64-bit Quad-Core ARM Cortex A53 as the original Pine A64 board, but at least Pine are doing a much better job this time around of managing user expectations.

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Pine64: The Un-Review

Even before the announcement and introduction of the Raspberry Pi 3, word of a few very powerful single board ARM Linux computers was flowing out of China. The hardware was there – powerful 64-bit ARM chips were available, all that was needed was a few engineers to put these chips on a board, a few marketing people, and a contract manufacturer.

One of the first of these 64-bit boards is the Pine64. Introduced to the world through a Kickstarter that netted $1.7 Million USD from 36,000 backers, the Pine64 is already extremely popular. The boards are beginning to land on the doorsteps and mailboxes of backers, and the initial impressions are showing up in the official forums and Kickstarter campaign comments.

I pledged $15 USD to the Pine64 Kickstarter, and received a board with 512MB of RAM, 4K HDMI, 10/100 Ethernet and a 1.2 GHz ARM Cortex A53 CPU in return. This post is not a review, as I can’t fully document the Pine64 experience. My initial impression? This is bad. This is pretty bad.

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