Hackaday Prize Entry: The 70s Called. They Want This Calculator

For those of us who grew up during TI’s calculator revolution, the concept of reverse polish notation (RPN) might be foreign. For other more worldly calculator users, however, the HP calculator was ubiquitous. Hewlett-Packard peaked (at least as far as calculators are concerned) decades ago and the market has remained dominated by TI since. Lucky for those few holdouts there is now a new microcode emulator of these classic calculators.

Called the NP25 (for Nonpariel Physical), the calculator fully emulates the HP-21, HP-25C and HP-33C. It’s a standalone microcode emulator, which means that these calculators work exactly as well as the original HP calculators of the 70s did. The new calculators, however, are powered by a low power MSP430G2553 processor and presumably uses many, many fewer batteries than the original did. It has an LED display to cut power costs as well, and was built with the goal of being buildable by the average electronics hobbyist.

Even if you didn’t grow up in the 70s with one of these in your desk drawer, it’d still be a great project and would help even the most avid TI user appreciate the fact that you don’t have to use RPN to input data into calculators anymore. Not that there’s anything wrong with that. This isn’t the only calculator we’ve featured here, either, so be sure to check out another free and open calculator for other calculator-based ideas.

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Ferrofluid Clock is a Work of Art

It is not usually too difficult to separate functionality from art. Consider a clock. It’s a machine that has a clear and distinct function. It provides information. Nothing could be more different from a clock on a wall than a piece of artwork.  A painting, for instance has no clear function and provides no information. It’s just…art. It’s nice to look at. If we were to ask you to build a functioning, information providing clock that is also a piece of artwork, you would surely have your hands full. Where would you even start? If your name was [Zelf Koelma], you’d grab a bottle of ferrofluid and build us a beautiful, almost mesmerizing clock.

clock_01There’s little to no information on the details of how the clock works other than the use of ferrofluid. But it’s not hard to guess that it uses dozens of electromagnets and an Arduino. You can even pick one up for a cool $8,300 if you’re lucky enough to get a spot on the list, as he’s only making 24 of them.

Want to make one of your own? Pick up some ferrofluid and keep us updated. We’d love to hear from you in the comments on how you’d implement a build like this one. We had a fun time hearing your ideas when we covered the clock made of clocks.

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Reflow Solder Your Micro SD to Ensure it Doesnt Go Anywhere

SD cards are great inexpensive storage for your embedded project. Using SPI,  they only take a few wires to hook up, and every micro-controller has a FAT file system interface to drop in your project. Problem with SD cards are the connectors.

Usually connectors cost more than the brains of your project,  and the friction fit, spring loaded contacts are not ideal for temperature swings, humidity and high vibration applications. Wouldn’t it be nice if you could just solder the thing down, especially if you know you are never going to remove it?

[Timothée] decided to try and succeeded in reflow soldering a Micro SD card direct to a breakout board. While starting as a what if experiment, the PCB was laid out in Ki-Cad and sent off to a fab. Once returned the Micro SD was fluxed, tinned and fluxed again, then reflowed using an IR setup.

The end result is a handy breakout board where you never have to worry about someone swiping the card to jam in their camera, and is ready for any breadboard project.

Adventures With Vacuum Deposition Power Supplies

[Jerry Biehler] called this a “fail of the week”, but of course failure is just another part of the hacker adventure. Fail and fail often!

[Jerry] has been slowly assembling a vacuum deposition system. These systems let you deposit thin films on a substrate. Vacuum deposition systems have all sorts of exciting applications, not only are they used in semiconductor manufacturing, but as [Ben Krasnow] has shown can create conductive transparent coatings. They’re even sometimes used for silvering mirrors.

A common feature of these systems is that they require high voltage, we’re not talking a few hundred volts or even a few thousand volts. But 10 to 20 kilovolts. You need such a high voltage in order to accelerate electrons and ions, which are used to eject atoms from a source and deposit them as a thin film on a substrate.

It was this HV supply [Jerry] was working on, cobbling the system together from parts found on eBay. Unfortunately [Jerry] could only reach 9kv unloaded, which we’d expect to drop considerably under load. So [Jerry] has now found a different solution. But this teardown and writeup still makes great reading.

We’re left to pondering on what projects the spare parts could be useful for: “I might be able to series the secondaries and get 30kv at 500ma! That would make one hell of a bug zapper! Actually these transformers scare the hell out of me….” me too Jerry! Me too!

Embed with Elliot: The Volatile Keyword

Last time on Embed with Elliot we covered the static keyword, which you can use while declaring a variable or function to increase the duration of the variable without enlarging the scope as you would with a global variable. This piqued the curiosity of a couple of our readers, and we thought we’d run over another (sometimes misunderstood) variable declaration option, namely the volatile keyword.

On its face, volatile is very simple. You use it to tell the compiler that the declared variable can change without notice, and this changes the way that the compiler optimizes with respect to this variable. In big-computer programming, you almost never end up using volatile in C. But in the embedded world, we end up using volatile in one trivial and two very important circumstances, so it’s worth taking a look.

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Arduboy Classic Plays On Original Game Boy Screen

The Arduboy is a Kickstarter backed, 8 bit video game console that mimics the look of a very tiny Nintendo Gameboy. The Arduboy Classic is actually using the case, button and LCD screen from a classic Game Boy.

[uXe] is using the same brains, an ATMEGA32U4, along with a 328 as a co-processor to handle the classic “creme-n-spinich” gameboy screen. 2K of dual port ram acts as a buffer between the two micro-controllers meaning they can not only run while not being in lock step with eachother, but that each micro can read or write to the ram at the same time.

Currently the whole setup is spread out on a breadboard while all the interfacing is worked out, but it is working quite well. Future plans are to make a drop in motherboard replacement for the classic game system, and there is ample room for all the new electronics on the original footprint.

If you’re unfamiliar with the Arduboy project, check out our interview with it’s creator, [Kevin Bates]. That and the demo of [uXe’s] hack based on the project are both found after the break.

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Lessons From The Fablab Masters

I spent some time recently at the Fab11 conference, a gathering of the people behind the Fab Labs that are springing up all over the world, where entrepreneurs, hackers and the curious can learn about making things. So, it was no surprise that this was a great place to pick up some tips on designing, building and hacking things. Here are a few of the lessons I picked up at this fascinating gathering of the fabbers.

Build Quickly

If you can make something in an hour, you’ll make it better in a day

said [Joris Van Tubergen]. He knows something about making unusual things because he 3D printed a full-sized Elephant. To do this, he worked out how to hack the Ultimaker 2 3D printer to print to an unlimited Z height by flipping the printer upside down and moving the Z motor to lift the printer rather than the print head. With a few tweaks to the software, he could then print full-height elephant slices to speed up the process. He is absolutely right: while it is tempting to endlessly fiddle with a concept on paper, you learn more by building a prototype, even if it doesn’t work.

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