Japanese ISS Supply Ship Dual-Purposed As Tether Experiment

January 27, 2017 by 35 Comments

When a rocket sends a capsule up with supplies for the International Space Station, they usually send a bunch of their trash back down with it, all of which burns up in the atmosphere on re-entry. But as long as you’ve got that (doomed) vehicle up there, you might as well do some science with it along the way. And that’s exactly what the Japanese Space Agency (JAXA) is doing with their Kounotori 6 supply ship that just left the ISS on Friday.

The experiment is with an electromagnetic tether that can be used to either turn electrical energy into kinetic or vice-versa. When you string a long conducting wire outwards from earth, the two ends pass through the earth’s magnetic field at different altitudes and thus pass through magnetic fields with different strengths, and an electrical potential is generated. In the KITE experiment (translated), a resistive load and an electron emitter on the supply ship are designed to burn up this electrical energy, lowering the ship’s kinetic energy, and dropping its orbit down to earth.
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Forth: The Hacker’s Language

January 27, 2017 by 240 Comments

Let’s start right off with a controversial claim: Forth is the hacker’s programming language. Coding in Forth is a little bit like writing assembly language, interactively, for a strange CPU architecture that doesn’t exist. Forth is a virtual machine, an interpreted command-line, and a compiler all in one. And all of this is simple enough that it’s easily capable of running in a few kilobytes of memory. When your Forth code is right, it reads just like a natural-language sentence but getting there involves a bit of puzzle solving.

robot_forth_had-colors
From Thinking FORTH (PDF)

Forth is what you’d get if Python slept with Assembly Language: interactive, expressive, and without syntactical baggage, but still very close to the metal. Is it a high-level language or a low-level language? Yes! Or rather, it’s the shortest path from one to the other. You can, and must, peek and poke directly into memory in Forth, but you can also build up a body of higher-level code fast enough that you won’t mind. In my opinion, this combination of live coding and proximity to the hardware makes Forth great for exploring new microcontrollers or working them into your projects. It’s a fun language to write a hardware abstraction layer in. Continue reading “Forth: The Hacker’s Language” →

Solar Controller Reverse Engineered In Both Directions

January 27, 2017 by 11 Comments

[Jared Sanson] has a solar power setup on his beach house, consisting of 6 panels and a 24V battery bank, supplied by Outback Inc. Their chargers and inverters pair over a seemingly proprietary connection with a controller known as the MATE. The MATE has a standard serial output which gives some details about the operation, but [Jared] wasn’t getting the detailed information they could get from the controller’s screen. This meant it was time to reverse engineer the proprietary connection instead, which [Jared] calls MateNET.

The controller interfaces with the chargers over a Cat5 cable. [Jared] initially suspected RS-485, but it turned out to be regular serial at 0-24V logic levels, at 9600 baud, 9n1. To figure out the pinout, [Jared] went through the MATE circuitry with a fine-toothed comb, discovering an ATMEGA32. Since both the MATE’s user output & its connection to the other equipment are both serial, a logic mux is used to split the ATMEGA32’s single UART between the two serial connections. With the physical layer sorted, it was time to figure out how the protocol worked.

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Let’s Prototype! This Filament End Needs 80 Decibels

January 27, 2017 by 49 Comments

Reaching the end of a spool of filament when 3D printing is inevitable. The result ranges from minor annoyance to ruined print. Recently, I needed to print a number of large jobs that used just over half a spool of plastic each. Unwilling to start every print with a fresh spool (and shelve a 60% used one afterward), I had a problem to solve. What my 3D printer needed was filament monitor, or at least that’s what I thought.

After reviewing some projects and aftermarket options, I ended up making my own. Like most prototypes, it wasn’t an instant success, but that’s fine. One of the goals of prototyping is not only to validate that the problems you’re solving are the same ones you think exist, but also to force other problems and issues you may not have considered to the surface. Failure is only a waste if nothing is learned, and the faster and cheaper that learning happens, the better.

Sensible design steps also help minimize waste, so I started by looking at what kind of solutions already existed.

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Riddle: What Metal Conducts Electricity, But Not Heat?

January 27, 2017 by 45 Comments

If you can’t answer the riddle, don’t feel bad. Metal conductors usually conduct electricity and heat. Usually, that’s true, but researchers at the Department of Energy’s Lawrence Berkeley National Laboratory and at the University of California, Berkeley, have found that vanadium dioxide can conduct electricity without conducting heat.

The Wiedemann-Franz Law states that good conductors of electricity are also good conductors of heat. Vanadium dioxide not only switches from an insulator to a conductor at 67C (152F), but it appears that it also doesn’t conduct as much heat as that law predicts while it is in its electrically conductive phase.

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The Soda Locker Vending Machine

January 27, 2017 by 27 Comments

With the rising popularity of electronic textbooks and laptops being used for schoolwork, the ubiquitous high school locker is becoming less and less necessary. So, students are left with a private storage space that they don’t really need. Why let it go to waste when you’re an enterprising young man with budding electronics and fabrication skills?

[Mistablik] is one such high school student who decided to take advantage of his unused locker. After a “wouldn’t it be cool if…” discussion with his friends, [Mistablik] decided to use his summer break to construct a soda vending machine that fit entirely within his school locker. Quite an ambitious project for a high school student, but the result speaks for itself.

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Build Your Own P-Brain

January 26, 2017 by 27 Comments

I don’t think we’ll call virtual assistants done until we can say, “Make me a sandwich” (without adding “sudo”) and have a sandwich made and delivered to us while sitting in front of our televisions. However, they are not completely without use as they are currently – they can let you know the time, weather and traffic, schedule or remind you of meetings and they can also be used to order things from Amazon. [Pat AI] was interested in building an open source, extensible, virtual assistant, so he built P-Brain.

Think of P-Brain as the base for a more complex virtual assistant. It is designed from the beginning to have more skills added on in order to grow its complexity, the number of things it can do. P-Brain is written in Node.js and using a Node package called Natural, P-Brain parses your request and matches it to a ‘skill.’ At the moment, P-Brain can get the time, date and weather, it can get facts from the internet, find and play music and can flip a virtual coin for you. Currently, P-Brain only runs in Chrome, but [Pat AI] has plans to remove that as a dependency. After the break, [Pat AI] goes into some detail about P-Brain and shows off its capabilities. In an upcoming video, [Pat AI]’s going to go over more details about how to add new skills. Continue reading “Build Your Own P-Brain” →