A Simple LED Flashlight Composed of a Relay and a Magnet

In our tips line we sometimes receive hacks that are amazing just because of their ingenuity. This relay-powered flashlight is definitely one of them. It has been named RattleGen by its creator [Berto], who apparently often makes simple hacks used in his everyday life (have a look at his YouTube channel).

To understand this hack, you first need to know (in case you didn’t already) that a magnet moving near a conductor (here a coil) induces a voltage at its terminals. This is called electromagnetic induction. In the picture you see above, you may distinguish a disassembled relay with a magnet located on the lever’s end. As a ferromagnetic metal is already placed inside the coil, the lever is by default ‘stuck’ in this position. By continuously pressing the latter on its other end, important voltage spikes are created at the coils terminals. [Berto] therefore used a bridge rectifier to transform the AC into DC, and a 1000uF capacitor to smooth the power sent to his super bright LED. A video of the system in action is embedded after the break.

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NESPoise – a Nice Looking NES Clone

[Dave] tipped us about the latest project he just finished: a posable, desktop NES clone arcade machine. This idea came to be when its creator gathered a few bits and pieces he had lying around: an NES Retro Entertainment System (Retrobit RES, found for less than $25) and an arcade stick with its buttons. [Dave] then bought a 7″ car DVD screen (less than $40) and started a first standard arcade-looking design with OpenSCAD. As the first draft was relatively boring, he let it mature for a bit until he got another idea, shown in the picture above.

The final result is made of 3D printed PLA and varnished luaun plywood which gives the console a VCS style retro look. Many hours were required to 3D print the different parts using a Makerbot Replicator 2. [Dave] disassembled his Retrobit RES to layout its parts inside the case and  also replaced the original voltage regulator with a 7805 on a big heatsink. This may be one of the best ‘nintendo’ hacks we have received over the years, but there have been others that also take cartridges.

Aluminum Unibody Nintendo 64

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[Travis] wanted us to take a look at his N64 portable to see if it could be featured on Hackaday. By the looks of it, we’re going to say hell yeah. Everything on this portable N64, down to the buttons, is milled from aluminum. It’s an amazing build that raises the bar of what a portabalized game system can be.

Inside this anodized enclosure is the circuit board from an original N64. To cut down on the size, [Travis] milled a new heat sink for the CPU and GPU. All the games – quite possibly all the games ever released for the N64 – are stored on an SD card and accessed through an EverDrive 64. Two 5000 mAh Lipo batteries provide three hours of play time on a beautiful high-res screen.

What’s even more amazing is that [Travis] machined all the parts on an exceedingly small, manual mini-mill. Truly a portabalized console for the ages.

You can check out a gallery of pics [Travis] sent in and his demo video below.

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DIY Metal Detector

Looking for a light project to teach young hackers some very basic electronics? Here’s a quick and easy weekend project, a simple metal detector!

We all know 555 timers are very useful and pop up in a wide range of projects, but did you know a metal detector is one of them? [vonPongrac] stumbled upon this handy guide, a free eBook on 50 555 Circuits, which contains many cool project ideas, including a simple metal detector circuit. It’s a very basic concept that uses a coil of copper wire as a home-made choke — when metal or a magnet comes near the coil, it varies the output frequency, and the 555 timer in turn, varies the output sound, alerting you of the presence of something metal nearby.

After the break there’s a video of it during its testing phases. If you don’t have a 555 on hand (tisk tisk) but still want to have some treasure hunting fun you can also build one based on an Arduino.

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Classic PDA finds second life as a network touch screen display

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[Tomas Janco] had an old Casio Pocket Viewer PDA collecting dust. Rather than throw it away, He decided to re-purpose it as a display for time, weather, and the current status of his garage door.

The Casio Pocket Viewer was a competitor to the Palm Pilot. The two systems even shared the same LCD resolution – 160×160 monochrome. [Tomas’] particular model is an S660, sporting 6 megabytes of ram and an NEC V30MZ (Intel 8086 compatible) processor. Similar to Palm, Casio made an SDK freely available.

The SDK is still available from Casio, and [Tomas] was able to get it running on his PC. Development wasn’t without pitfalls though. The Pocket Viewer SDK was last updated in April of 2001. Software is written in C, but the then new C99 standard is not supported. The SDK does include a simulator and debugger, but it too is not as polished as todays systems – every simulator startup begins with setting the clock and calibrating the touch screen. Keep reading after the jump to learn about the rest of the hurdles he overcame to pull this one off.

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Prototyping a low-resolution handheld gaming rig

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[Jason] has been hard at work on this Arduino-based low-res gaming platform. He even had a fab house deliver circuit boards to pull everything together. It’s a little small in his hands, and the graphics are limited to the 8×8 pixels provided by the display. But it still looks like a lot of fun and the code was written to make adding new games quite painless.

The board hosts an ATmega328 which drives the bi-color LED display using a pair of TPIC6B595 shift registers. Control is provided by a collection of buttons to either side of the display. The unit is powered by three AAA batteries held in a pack soldered to the back side of the PCB.

The image above shows [Jason] giving a Space Invaders game a try. The clip after the break shows respectable action, sound from a piezo buzzer, and it even scrolls your score at the end of the game. But you’re not limited to just one title. Adding new games is as easy as implementing a class in a new header file. You can get a feel for how this is set up by viewing the source code repo.

This reminds us of the Pixel Bros low-res system.

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Tamagotchi hacking, in depth

In this strangely fascinating talk, you can follow along as [Natalie Silvanovich] reverse engineers some tomogotchi. Even if you have no interest whatsoever in tomogotchi, you’ll probably pick up a trick or two by listening to how she went about taking over the toy. She can now push her own images to the screen, and evolve her tomogatchi at will.

Listening to her story you might be able to pick up a few tricks as she takes almost every angle possible. She uncovers the black blobs, she attempts to socially engineer her way into datasheets, decaps chips, she dumps and breaks down code. It is also worth noting that, in the beginning, internet electronics enthusiasts were adamant that it just had a PIC processor inside and they were wrong. Having an internet full of experts is a wonderful thing, except when it isn’t.

Then again, having that internet full of experts might be her savior in the end, she’s missing a piece of software and asking if anyone has it available.

[via Adafruit]