Month: June 2017

Ask Hackaday: SawStop — Bastion Of Safety Or Patent Troll

June 22, 2017 by 221 Comments

At first glance, SawStop seems like a hacker’s dream. A garage tinkerer comes up with a great idea, builds a product around it, and the world becomes a better place. As time has gone on, other companies have introduced similar products. Recently, SawStop successfully stopped Bosch from importing saws equipped with their Reaxx safety system into the USA. This not only impacts sales of new saws, but parts for existing equipment. Who gets screwed here? Unfortunately, it’s the owners of the Bosch saws, who now have a safety feature they might not be able to use in the future. This has earned some bad press for SawStop in forums and on websites like Reddit, where users have gone as far as to call SawStop a patent troll. Is that true or just Internet puffery? Read on and decide for yourself.

Continue reading “Ask Hackaday: SawStop — Bastion Of Safety Or Patent Troll” →

Detecting Mobile Phone Transmissions With A Sound Card

June 22, 2017 by 23 Comments

Anyone who had a cheap set of computer speakers in the early 2000s has heard it – the rhythmic dit-da-dit-dit of a GSM phone pinging a cell tower once an hour or so. [153armstrong] has a write up on how to capture this on your computer. 

It’s incredibly simple to do – simply plug in a set of headphone to the sound card’s microphone jack, leave a mobile phone nearby, hit record, and wait. The headphone wire acts as an antenna, and when the phone transmits, it induces a current in the wire, which is picked up by the soundcard.

[153armstrong] notes that their setup only seems to pick up signals from 2G phones, likely using GSM. It doesn’t seem to pick up anything from 3G or 4G phones. We’d wager this is due to the difference in the way different cellular technologies transmit – let us know what you think in the comments.

This system is useful as a way to detect a transmitting phone at close range, however due to the limited bandwidth of a computer soundcard, it is in no way capable of actually decoding the transmissions. As far as other experiments go, why not use your soundcard to detect lightning?

Hacked Sea Scooter Lives Another Day

June 22, 2017 by 6 Comments

The Seadoo GTI Sea Scooter is a simple conveyance, consisting of a DC motor and a big prop in a waterproof casing. By grabbing on and firing the motor, it can be used to propel oneself underwater. However, [ReSearchITEng] had problems with their unit, and did what hackers do best – cracked it open to solve the problem.

Investigation seemed to suggest there were issues with the logic of the motor controller. The original circuit had a single FET, potentially controlled through PWM.  The user interfaced with the controller through a reed switch, which operates magnetically. Using reed switches is very common in these applications as it is a cheap, effective way to make a waterproof switch.

It was decided to simplify things – the original FET was replaced with a higher-rated replacement, and it was switched hard on and off directly by the original reed switch. The logic circuitry was bypassed by cutting traces on the original board. [ReSearchITEng] also goes to the trouble of highlighting potential pitfalls of the repair – if the proper care isn’t taken during the reassembly, the water seals may leak and damage the electronics inside.

Overall it’s a solid repair that could be tackled by any experienced wielder of a soldering iron, and it keeps good hardware out of the landfill. For another take on a modified DC motor controller, check out the scooter project of yours truly.

 

Decoding NRSC-5 With SDR To Get In Your Car

June 21, 2017 by 14 Comments

NRSC-5 is a high-definition radio standard, used primarily in the United States. It allows for digital and analog transmissions to share the original FM bandwidth allocations. Theori are a cybersecurity research startup in the US, and have set out to build a receiver that can capture and decode these signals for research purposes, and documented it online.

Their research began on the NRSC website, where the NRSC-5 standard is documented, however the team notes that the audio compression details are conspicuously missing. They then step through the physical layer, multiplexing layer, and finally the application layer, taking apart the standard piece by piece. This all culminates in the group’s development of an open-source receiver for NRSC-5 that works with RTL-SDR – perhaps the most ubiquitous SDR platform in the world. 

The group’s primary interest in NRSC-5 is its presence in cars as a part of in-car entertainment systems. As NRSC-5 allows data to be transmitted in various formats, the group suspects there may be security implications for vehicles that do not securely process this data — getting inside your car through the entertainment system by sending bad ID3 tags, for instance. We look forward to seeing results of this ongoing research.

[Thanks to Gary McMaster for the tip!]

The Silence Of The Fans

June 21, 2017 by 50 Comments

The good thing about using a server-grade machine as your desktop is having raw computing power at your fingertips. The downside is living next to a machine that sounds like a fleet of quadcopters taking off. Luckily, loud server fans can be replaced with quieter units if you know what you’re doing.

Servers are a breed apart from desktop-grade machines, and are designed around the fact that they’ll be installed in some kind of controlled environment. [Juan] made his Dell PowerEdge T710 tower server a better neighbor by probing the PWM signals to and from the stock Dell fans; he found that the motherboard is happy to just receive a fixed PWM signal that indicates the fans are running at top speed. Knowing this, [Juan] was able to spoof the feedback signal with an ATtiny85 and a single line of code. The noisy fans could then be swapped for desktop-grade fans; even running full-tilt, the new fans are quieter by far and still keep things cool inside.

But what to do with all those extra fans? Why not team them up with some lasers for a musical light show?

Robot Draws Using Robust CNC

June 21, 2017 by 9 Comments

While initially developed for use in large factory processes, computer numeric control (CNC) machines have slowly made their way out of the factory and into the hands of virtually anyone who wants one. The versatility that these machines have in automating and manipulating a wide range of tools while at the same time maintaining a high degree of accuracy and repeatability is invaluable in any setting. As an illustration of how accessible CNC has become, [Arnab]’s drawing robot uses widely available tools and a CNC implementation virtually anyone could build on their own.

Based on an Arudino UNO and a special CNC-oriented shield, the drawing robot is able to execute G code for its artistic creations. The robot is capable of drawing on most flat surfaces, and can use almost any writing implement that will fit on the arm, from pencils to pens to brushes. Since the software and hardware are both open source, this makes for an ideal platform on which to build any other CNC machines as well.

In fact, CNC is used extensively in almost everything now, and are so common that it’s not unheard of to see things like 3D printers converted to CNC machines or CNC machines turned into 3D printers. The standards used are very well-known and adopted, so there’s almost no reason not to have a CNC machine of some sort lying around in a shop or hackerspace. There are even some art-based machines like this one that go much further beyond CNC itself, too.

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Dumping Synth ROMs And Avoiding Bitrot

June 21, 2017 by 24 Comments

Bitrot is setting in, and our digital legacy is slowly turning to dust. Efforts preserve our history are currently being undertaken numerous people around the Internet, and [Jason Scott] just got an automated CD ripper, so everything is kinda okay.

However, there is one medium that’s being overlooked. ROMs, and I don’t mean video game cartridges. In the 80s, mask ROMs were everywhere, found in everything from talking cars to synthesizers.

[Ali] bought a Korg i5m workstation from eBay a few years ago, but this unit had a problem. Luckily, he had a similar synth with the same samples stored on board. There was only one way to find out if bitrot was the cause: desoldering the chips and dumping all the information.

After fiddling around with his broken synth, [Ali] still had a problem with the sound output. Deciding the ROM chips had to be the issue, [Ali] desoldered the chips and ordered a breadboard SOP44 adapter after deciding soldering wires to each lead of the chip was a bad idea. This adapter was connected to an Arduino Mega — still the best tool for weird tasks like this — and the contents of the ROM were dumped to a PC with the help of a helpful Arduino sketch.

Dumping the ROMs took about 15 minutes, and that’s if he was able to maintain a good connection between the chip and Arduino for that long. [Ali] wrote an improved ROM reader after much trial and error, and was eventually able to get the same data out of the same chip eventually.

While the broken synth hasn’t been repaired yet, at least [Ali] has the important bits off of this antique instrument. That’s good enough for now, but [Ali] intends to take this project to completion and get those vintage samples playing out of this great old synth.