Security system gives you a call when it senses intruders

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[Dimitris] decided to build a homemade alarm system, but instead of triggering a siren, sending an SMS message, or Tweeting about an intrusion, he preferred that his system call him when there was trouble afoot. He says that he preferred a call over text messaging because there are no charges associated with the call if the recipient does not pick up the line, which is not the case with SMS.

The system is based around an off the shelf motion detector that was hacked to work with an old mobile phone. The motion detector originally triggered a siren, but he stripped out the speaker and wired it to a bare bones Arduino board he constructed. The Arduino was in turn connected to the serial port of an unused Ericssson T10s mobile phone. This allows the Arduino to call his mobile phone whenever the motion detector senses movement.

The system looks to be quite useful, and while [Dimitris] didn’t include all of the code he used, he says others should be able to replicate his work without too much trouble.

This marriage proposal is the best PCB design ever

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While you will often see hacks on this site that feature high voltage, fire, and metal, that doesn’t mean that hackers, makers, and electronics geeks don’t have a soft side. In fact, we find the opposite to be true the vast majority of the time.

Take for instance [Bill Porter].

You may have seen his projects and tutorials featured here a time or two, and though I have never met him, he seems like a great guy whose heart is in the right place.

He recently decided that his college sweetheart was “the one” and had to think of a clever and surprising way to pop the question to a girl who is always one step ahead of the curve. [Mara (soon to be) Porter] was working on a project that required a custom PCB, and having never ordered one before, [Bill] was happy to help her get things in order. After sending the schematics off to [Laen] at DorkbotPDX, [Bill] fired off another email asking to have his proposal silk screened on the boards. [Laen] said he was happy to help, and so the wait began.

The boards arrived a few weeks later, and the rest, they say, was history.

How did it go? We’re guessing you’ve figured it out by now, but be sure to swing by [Bill’s] site to see how it all went down.

You know you want to…you big softie!

Engine Hacks: Riquimbilis, or: what we’d do if we couldn’t buy a car

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After the United States enacted a near-total economic embargo against Cuba in 1962, American export of Detroit Iron came to a halt. Since then, some Cubans have been lucky enough to own a classic Chevy or Buick. Soviet imports of Volgas stopped in the 1990s. With a dearth of any sort of motorized transport (and a public transport system that’s even worse than America’s), some Cubans went with the only reasonable solution: they built Rikimbilis, bicycles and engines hacked together into a moped.

Most rikimbilis are based around Chinese bicycles with a motor ‘obtained’ through ‘non-conventional means’. The exhaust can be fabricated from just about any metal tube available, and a plastic soda bottle is the gas tank of choice. Everything on these bikes is done for reasons of economy and availability, and the fuel efficiency is unbeatable with some rikinbilis getting 120 mpg.

Because they’re not especially safe, Riquimbilis are illegal in Cuba, but the police generally turn a blind eye to their use. Lately the Cuban government has begun cracking down on riquimbilis, but with not many cars to go around these machines of necessity will most likely continue plying Havana boulevards.

Recovering data for a homemade Cray

In our hubris, we pat ourselves on the back when we’re able to pull data off our old SCSI drives. [Chris Fenton]‘s attempt to get an OS for a homebrew Cray-1 puts us rightfully to shame.

Last year we saw [Chris]‘ fully functional 1/10th scale Cray-1 supercomputer built around FPGA. While the reproduction was nearly cycle-accurate, [Chris] hasn’t had an opportunity to test out his system because of the lack of available Cray software. A former Cray employee heard of his plight and loaned an 80 Megabyte CDC 9877 disk pack to in the hope of getting some system software.

[Chris] acquired a monstrous 100 pound disk drive to read the disk pack, but after 30 years in storage a lot of electrical problems cropped up. Since reading the drive digitally proved to be an exercise in futility, [Chris] hit upon the idea of taking analog data straight from the read head. This left him with a magnetic image of the disk pack that was ready for some data analysis.

After the disk image was put up on the Internet, the very talented [Yngve AAdlandsvik] figured out the data, header, and error correction formats and sent [Chris] a Python script to tease bits from the analog image. While no one is quite sure what is on the disk pack provided by the Cray employee, [Chris] is remarkably close to bringing the Cray-1 OS back from the dead. There’s also a great research report [Chris] wrote as penance for access to the CDC disk drive. Any Hack A Day readers feel like looking over the data and possibly giving [Chris] a hand?

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