Coleco In Spat With ColecoVision Community

May 25, 2017 by Jenny List 82 Comments

If you were a child of the late 1970s or early 1980s, the chances are that your number one desire was to own a games console. The one to have was the Atari 2600, notwithstanding that dreadful E.T. game.

Of course, there were other consoles during that era. One of these also-ran products came from Coleco, a company that had started in the leather business but by the mid 1970s had diversified into handheld single-game consoles. Their ColecoVision console of 1982 sold well initially, but suffered badly in the video game crash of 1983. By 1985 it was gone, and though Coleco went on to have further success, by the end of the decade they too had faded away.

The Coleco story was not over though, because in 2005 the brand was relaunched by a successor company. Initially it appeared on an all-in-one retro console, and then on an abortive attempt to crowdfund a new console, the Coleco Chameleon. This campaign came to a halt after the Chameleon prototypes were shown to be not quite what they seemed by eagle-eyed onlookers. Continue reading “Coleco In Spat With ColecoVision Community” →

Ohm? Don’t Forget Kirchhoff!

May 25, 2017 by Al Williams 52 Comments

It is hard to get very far into electronics without knowing Ohm’s law. Named after [Georg Ohm] it describes current and voltage relationships in linear circuits. However, there are two laws that are even more basic that don’t get nearly the respect that Ohm’s law gets. Those are Kirchhoff’s laws.

In simple terms, Kirchhoff’s laws are really an expression of conservation of energy. Kirchhoff’s current law (KCL) says that the current going into a single point (a node) has to have exactly the same amount of current going out of it. If you are more mathematical, you can say that the sum of the current going in and the current going out will always be zero, since the current going out will have a negative sign compared to the current going in.

You know the current in a series circuit is always the same, right? For example, in a circuit with a battery, an LED, and a resistor, the LED and the resistor will have the same current in them. That’s KCL. The current going into the resistor better be the same as the current going out of it and into the LED.

This is mostly interesting when there are more than two wires going into one point. If a battery drives 3 magically-identical light bulbs, for instance, then each bulb will get one-third of the total current. The node where the battery’s wire joins with the leads to the 3 bulbs is the node. All the current coming in, has to equal all the current going out. Even if the bulbs are not identical, the totals will still be equal. So if you know any three values, you can compute the fourth.

If you want to play with it yourself, you can simulate the circuit below.

The current from the battery has to equal the current going into the battery. The two resistors at the extreme left and right have the same current through them (1.56 mA). Within rounding error of the simulator, each branch of the split has its share of the total (note the bottom leg has 3K total resistance and, thus, carries less current).

Continue reading “Ohm? Don’t Forget Kirchhoff!” →

NIST Helps You With Cryptography

May 25, 2017 by Elliot Williams 33 Comments

Getting cryptography right isn’t easy, and it’s a lot worse on constrained devices like microcontrollers. RAM is usually the bottleneck — you will smash your stack computing a SHA-2 hash on an AVR — but other resources like computing power and flash code storage space are also at a premium. Trimming down a standard algorithm to work within these constraints opens up the Pandora’s box of implementation-specific flaws.

NIST stepped up to the plate, starting a lightweight cryptography project in 2013 which has now come out with a first report, and here it is as a PDF. The project is ongoing, so don’t expect a how-to guide. Indeed, most of the report is a description of the problems with crypto on small devices. Given the state of IoT security, just defining the problem is a huge contribution.

Still, there are some concrete recommendations. Here are some spoilers. For encryption, they recommend a trimmed-down version of AES-128, which is a well-tested block cipher on the big machines. For message authentication, they’re happy with Galois/Counter Mode and AES-128.

I was most interested in hashing, and came away disappointed; the conclusion is that the SHA-2 and SHA-3 families simply require too much state (and RAM) and they make no recommendation, leaving you to pick among less-known functions: check out PHOTON or SPONGENT, and they’re still being actively researched.

If you think small-device security is easy, read through the 22-question checklist that starts on page twelve. And if you’re looking for a good starting point to read up on the state of the art, the bibliography is extensive.

Your tax dollars at work. Thanks, NIST!

And thanks [acs] for the tip!

These Engineering Ed Projects Are Our Kind Of Hacks

May 25, 2017 by Mike Szczys 23 Comments

Highly polished all-in-one gear for teaching STEM is one way to approach the problem. But for some, they can be intimidating and the up-front expenditure can be a barrier to just trying something before you’re certain you want to commit. [Miranda] is taking a different approach with the aim of making engineering education possible with junk you have around the house. The point is to play around with engineering concepts with having to worry about doing it exactly right, or with exactly the right materials. You know… hacking!

Continue reading “These Engineering Ed Projects Are Our Kind Of Hacks” →

Radar Sensors Put To The Test

May 24, 2017 by Al Williams 68 Comments

[Andreas Spiess] picked up a few inexpensive radar sensors. He decided to compare the devices and test them and–lucky for us–he collected his results in a video you can see below.

The questions he wanted to answer were:

Are they 3.3 V-compatible?
How much current do they draw?
How long to they show a detection?
How far away can they detect the motion of a typical adult?
What is the angle of detection?
Can they see through certain materials?
Can the devices coexist with other devices in the same area? What about WiFi networks?

Good list of questions, and if you want to know the answers, you should watch the video.

Continue reading “Radar Sensors Put To The Test” →

What Lies Within: SMT Inductor Teardown

May 24, 2017 by Dan Maloney 10 Comments

Ever wonder what’s inside a surface-mount inductor? Wonder no more as you watch this SMT inductor teardown video.

“Teardown” isn’t really accurate here, at least by the standard of [electronupdate]’s other component teardowns, like his looks inside LED light bulbs and das blinkenlights. “Rubdown” is more like it here, because what starts out as a rather solid looking SMT component needs to be ground down bit by bit to reveal the inner ferrite and copper goodness. [electronupdate] embedded the R30 SMT inductor in epoxy and hand lapped the whole thing until the windings were visible. Of course, just peeking inside is never enough, so he set upon an analysis of the inductor’s innards. Using a little careful macro photography and some simple image analysis, he verified the component’s data sheet claims; as an aside, is anyone else surprised that a tiny SMT component can handle 30 amps?

Looking for more practical applications for decapping components? How about iPhone brain surgery?

Continue reading “What Lies Within: SMT Inductor Teardown” →

Only 90s Kids Will Appreciate This Prototype

May 24, 2017 by Brian Benchoff 34 Comments

[Madox] is a trackball user, which is fine; we at Hackaday respect and appreciate those who live alternative lifestyles. As you would expect, there aren’t many makes and models of trackballs being sold, and [Madox] wanted something ergonomic. A DIY solution was necessary, but how to you model something ‘ergonomic’ before printing it out? Floam, apparently.

Floam is a sticky, moldable goo originally sold as the follow-up to Nickelodeon’s Gak in the early 1990s. It consists of styrofoam pellets held together with a colored binder that doesn’t leave a mess and doesn’t dry out. While the Nickelodeon version is lost to the sands of time, a Floam-like substance is available at any toy store. [Madox] picked up a few blister packs and began modeling his ideal trackball.

With the proper shape in hand, [Madox] needed a way to get this design into a computer. Photogrammetry is the solution, and while earlier experiments with Autodesk Catch were successful, Autodesk has morphed and rebranded their photogrammetry software into Autodesk ReMake. Turing a pile of styrofoam balls into a 3D model is as simple as taking a bunch of pictures and uploaded to Autodesk’s ‘cloud’ service.

In just a few minutes, a proper 3D mesh arrived from the Autodesk mothership, and [Madox] took to importing this model into Fusion 360, fiddling with chamfers, and eventually got to the point where a 3D printer was necessary. It took a few revisions, but now [Madox] has a custom designed trackball that was perfectly ergonomic.