An Open Source Lead Tester

If you’ve ever needed an example of colossal failure of government actors, you need only to look at Flint, Michigan’s water crisis. After the city of Flint changed water supplies from Detroit to the Flint river, city officials failed to add the correct corrosion inhibitors. This meant that lead dissolved into the water, thousands of children were exposed to lead in drinking water, a government coverup ensued, [Erin Brockovich] showed up, the foreman of the Flint water plant was found dead, and the City Hall office containing the water records was broken into.

Perhaps inspired by Flint, [Matthew] is working on an Open Source Lead Tester for his entry into the 2016 Hackaday Prize.

[Matthew]’s lead tester doesn’t test the water directly. Instead, it uses a photodiode and RGB LED to look at the color of a lead test strip. These results are recorded, and with a bit of a software backend, an entire city can be mapped for lead contamination in a few days with just a few of these devices.

One problem [Matthew] has run into is the fact the Pi does not have analog to digital conversion, making reading a photodiode a little harder than just plugging a single part into a pin header and watching an analog value rise and fall. That really shouldn’t be a problem – ADCs are cheap, especially if you only need a single channel of analog input with low resolution. [Matthew] is also looking into using the Pi webcam for measuring the lead test strip. There are a lot of decisions to make, but any functional device that comes out of this project will be very useful in normal, functioning governments. And hopefully in Flint, Michigan too.

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Soldering Iron Cauterization

Medical hacks are not for the weak of stomach, so read further at your own risk. [Todd Harrison] shows you how to remove a stubborn skin wart using a good ol’ soldering iron, and a fair endurance for pain. After all, cauterization is a well known and documented medical procedure. If you have the stomach for this, read on, or better, check out his 9 minute video after the break. If there are kids around, turn down the volume between 1:40 to 2:20.

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DNA Extraction With A 3D-Printed Centrifuge

[F.Lab] is really worried that we are going to prepare a DNA sample from saliva, dish soap, and rubbing alcohol in their 3D-printed centrifuge and then drink it like a shot. Perhaps they have learned from an horrific experience, perhaps biologists have different dietary requirements. Either way, their centrifuge is really cool. Just don’t drink the result. (Ed note: it’s the rubbing alcohol.)

The centrifuge was designed in Sketch-Up and then 3D printed. They note to take extra care to get high quality 3D prints so that the rotor isn’t out of balance. To get the high speeds needed for the extraction, they use a brushless motor from a quadcopter. This is combined with an Arduino and an ESC. There are full assembly instructions on Thingiverse.

[F.Lab] has some other DIY lab equipment designs, such as this magnetic stirrer. Which we assume you could use to make a shot if you wanted to. However, it’s probably not a good idea to mix lab supplies and food surfaces. Video after the break.

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Retrotechtacular: TV Troubleshooting

As technology advances, finding the culprit in a malfunctioning device has become somewhat more difficult. As an example, troubleshooting an AM radio is pretty straightforward. There are two basic strategies. First, you can inject a signal in until you can hear it. Then you work backwards to find the stage that is bad. The other way is to trace a signal using a signal tracer or an oscilloscope. When the signal is gone, you’ve found the bad stage. Of course, you still need to figure out what’s wrong with the stage, but that’s usually one or two transistors (or tubes) and a handful of components.

A common signal injector was often a square wave generator that would generate audio frequencies and radio frequency harmonics. It was common to inject at the volume control (easy to find) to determine if the problem was in the RF or audio sections first. If you heard a buzz, you worked backwards into the RF stages. No buzz indicated an audio section problem.

A signal tracer was nothing more than an audio amplifier with a diode demodulator. Starting at the volume control was still a good idea. If you heard radio stations through the signal tracer, the RF section was fine. Television knocked radio off of its pedestal as the primary form of information and entertainment in most households, and thus the TV repair industry was created.

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The Dark Arts: Anonymity

Love him or hate him, Edward Snowden knew a thing or two about anonymity. In June of 2013, he blew the whistle on the NSA’s out-of-control programs that can target virtually anyone plugged into the digital age. The former CIA employee was working as a contractor for the NSA, where he had access to highly classified documents for many of these general populace surveillance programs. He eventually took off to Hong Kong and released the documents to a handful of reporters. One of these documents was a power point presentation of the NSA complaining about how the TAILS operating system was a major thorn in their side. Naturally, Snowden insisted that the reporters and himself only communicate via the TAILS O/S. He used PGP, which is an encryption method with the highly sophisticated title of “Pretty Good Privacy”, and asked not to be quoted at length for fear of identification via stylometry.

In this article, we’re going to go over the basics of anonymity, and introduce you to methods of staying anonymous while online.

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Not Even Hamsters Are Safe From The Internet Of Things

The internet of things is this strange marketing buzzword that seems to escape from the aether and infect our toasters and refrigerators. Now even a hamster is not safe.

[Mifulapirus]’s hamster, Ham, was living a pleasant hamster life. Then his owner heard about another hamster named Sushi, whose running wheel stats were broadcasted to the internet. Not to be left behind, Ham’s wheel was soon upgraded. Now Ham is burdened by the same social pressures our exercise apps try to encourage us to use. No, we are most certainly not going to tell our friends about two fourteen minute miles with a twenty minute coffee break in the middle, MapMyRun, we are not.

The feat of techno enslavement for the little hamster was accomplished with a custom board, an esp8266, and an arduino as described in the instructable. The arduino can be left out of the project now that the libraries have been ported to the esp8266. A hall effect sensor detects when the 3D printed hamster wheel is spinning.

If you’d like to check in on Ham, the little guy is alive and well, and the twitter is here. It looks like it’s been upgraded since the original article was posted. Now it shows when Ham is awake and running around the cage doing hamster errands.

Volkswagen Beetle – The Most Hackable Car

If you build a better mousetrap, the world will beat a path to your door. Of course it helps if your mousetrap is reliable, simple, cheap, and easy to work on. In the car world, look no further than arguably the most successful, and most hackable, car in history: the Volkswagen Type 1, more commonly known as the Beetle. The ways in which this car was modified to suit the needs of a wide range of people over its 65-year-long production run proves that great design, ease of use, and simplicity are the keys to success, regardless of the project or product.

Built by Ferdinand Porsche in 1930’s Germany, the Beetle was designed to be a car for anyone and everyone. Its leader at the time wanted a true “people’s car” (i.e. “Volkswagen”) that was affordable for a German family, could reliably travel at sustained highway speeds on the new German autobahns, and easily be repaired by its owners. The car features an air-cooled engine for simplicity and cost savings: no radiator, water pump, or coolant, plus reduced overall complexity. The engine can be easily removed by disconnecting the fuel line, the throttle cable, and the four bolts that hold it to the transaxle. The entire body is held on to the chassis by eighteen bolts and is also easy to remove by today’s standards. There’s no air conditioning, no power steering, and a rudimentary heater of sorts for the passenger cabin that blows more hot air depending on how fast the engine is running. But possibly the best example of its simplicity is the fact that the windshield washer mechanism is pressurised with air from the over-inflated spare tire, eliminating the need to install another piece of equipment in the car.

It’s not too big of a leap to realize how easily hackable this car is. Even Volkswagen realized this and used the platform to build a number of other vehicles: the Type 2 (otherwise known as the bus, van, hippie van, Kombi, etc.) the eclectic Karmann Ghia, and the Types 3 and 4. Parts of the Type 1 were used to build the Volkswagen 181, commonly referred to as “the Thing”. Ferdinand Porsche also used design elements and other parts of the Type 1 to build the first Porsche, essentially making a souped-up Beetle. The rear-engine, rear-wheel drive layout of modern Porsches is a relic of this distant Beetle cousin. But the real magic is what people started doing to the Beetles in their backyards in the ’60s and 70s: turning them into buggies, off road machines, race cars, and hot rods that are still used today.

At some point around this time, a few people realized that the Beetle was uniquely suited to off-road racing. The type of suspension combined with the rear-engine, rear-wheel-drive layout meant that even without four-wheel drive, this car could excel in desert racing. There are still classes in this race for stock Beetles and modified Beetles called Baja Bugs.

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