Hackaday Prize Entry: An Open Radiation Detector

October 14, 2017 by 38 Comments

For his Hackaday Prize entry, [Carlos] is pushing the boundaries of what can be built with PCBs. He’s designed a very low-cost radiation detector that leverages pick and place machines, off-the-shelf components, and very simple electronics. It’s a novel ion chamber design, and if you ever needed a low-cost, easily manufacturable radiation detector, this is the project you want.

Instead of a Geiger tube or a spark detectors, this radiation detector uses an ionization chamber to detect radiation. This project was inspired by the work of [Charles Wenzel] and [Alan Yates], and the implementation is actually pretty simple. A metal can — or some other type of enclosure — is electrified, and a single wire is stuck right into the middle of the can. When alpha and beta particles enter the can, air molecules are ionized, and attracted to either the can or the wire by a difference in voltage. A tiny bit of current flows between the can and the wire, which can be detected if you have a sufficiently sensitive circuit.

The basic idea is well-publicised and well-understood. What [Carlos] is doing with this project is making an ionization chamber easily manufacturable. He’s doing this entirely with standard PCBs and solder instead of paint cans, RF connectors, and deadbugged transistors of the earlier experiments. The resulting PCB actually looks like something that wasn’t put together in a garage (even though it probably was), and is an amazing entry for the Hackaday Prize.

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Spy Tech: Nonlinear Junction Detectors

September 20, 2017 by 121 Comments

If you ever watch a spy movie, you’ve doubtlessly seen some nameless tech character sweep a room for bugs using some kind of detector and either declare it clean or find the hidden microphone in the lamp. Of course, as a hacker, you have to start thinking about how that would work. If you had a bug that transmits all the time, that’s easy. The lamp probably shouldn’t be emitting RF energy all the time, so that’s easy to detect and a dead give away. But what if the bug were more sophisticated? Maybe it wakes up every hour and beams its data home. Or perhaps it records to memory and doesn’t transmit anything. What then?

High-end bug detectors have another technique they use that claims to be able to find active device junctions. These are called Nonlinear Junction Detectors (NLJD). Spy agencies in the United States, Russian and China have been known to use them and prisons employ them to find cell phones. Their claim to fame is the device doesn’t have to be turned on for detection to occur. You can see a video of a commercial NLJD, below

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Water Softener Monitor

Water Softener Level Detector Keeps You Out Of Trouble With Wife

October 29, 2014 by 81 Comments

Some households have water supplies that contain higher than desired levels of minerals. This condition is called hard water. There is nothing harmful about hard water but it does leave mineral deposits on pipes and appliances and makes cleaning a little bit more difficult. The solution is to have a water softener system which is basically a tank filled with salt that the household water passes through. This tank has to be refilled about every month and [David] was catching a little flak from his wife because he kept forgetting to fill it. He then set out to do what any great husband would do and built a Water Softener Monitor that reports the quantity of salt in the basement tank up to the living quarters.

[David] started thinking that he should test the salinity of the water to determine if salt needed to be added but after thinking about it for a while decided against it because any metal in that salty water would surely corrode. A non-contact approach would be to use an IR distance sensor mounted to the top of the tank and measure the distance to the pile of salt that slowly lowers as it dissolves into the water. In this case, he used a Sharp GP2D12 that can measure accurately from 10 to 80cm.

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Metal Detection Using An Inductor Instead Of A Clock Crystal.

May 8, 2012 by 13 Comments

This project from a few years back is an interesting take on a metal detector. Instead of building a detection circuit, [Bruno Gavand] replaced the external clock crystal with an inductor. Here you can see the inductor coil next to the PIC 12F683. You can see two components jumping from one breadboard to the other. These are smoothing capacitors on the inductor lines.

The watchdog timer for the chip is run by the internal RC oscillator. When the external crystal receives a pulse due to metal inducing a current in the coil, the value of the watchdog timer is compared to it. This data is filtered and if the proper parameters are present the green LED blinks. This is bicolor LED. If the inductor circuit is functioning properly it will blink red at power up. [Bruno] says that results will vary based on that inductor so you may need to try a few to get the calibration light to blink.

We’re thinking this would make a simple stud finder (by detecting where the nails/screws are in the wall). Check out the demo after the break, then let us know what you would use this for by leaving a comment.

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Excuse Me, Your Tie Is Unzipped

January 5, 2023 by 102 Comments

If you ask your typical handyperson what’s the one thing you need to fix most things, the answer might very well be duct tape. But second place — and first place in some circles — would have to be zip ties. These little wonders are everywhere if you look for them. But they are a relatively recent invention and haven’t always had the form they have today.

The original zip tie wasn’t called a zip tie or even a cable tie. In 1958 they were called Ty-Raps and produced by a company called Thomas and Betts. Originally meant to improve aircraft wiring harnesses, they found their way into various electronic equipment and packaging uses. But they’ve also become helpful in very unusual places too. A policeman trying to round up rioters would have problems carrying more than a few conventional handcuffs. But flexible cuffs based on zip ties are lightweight and easy to carry. Colon surgeons sometimes use a modified form of zip tie during procedures.

History

Maurus Logan worked for the Thomas and Betts company. In 1956, he was touring an aircraft manufacturing plant. Observing a wiring harness being put together on a nail board, similar to how car harnesses are made, he noted that the cables were bundled with waxed twine or nylon cord. A technician had to tie knots in the cord, sometimes cutting their fingers and often developing calluses. In addition, the twine was prone to fungal growth, requiring special treatment.

Logan kept turning the problem over in his mind and tried various approaches. By 1958, he had a patent for the Ty-Rap. The tie was lightweight, easy to install, easy to remove, and inexpensive.

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The Problem With Passwords

January 3, 2023 by 129 Comments

By now it’s probable that most readers will have heard about LastPass’s “Security Incident“, in which users’ password vaults were lifted from their servers. We’re told that the vaults are encrypted such that they’re of little use to anyone without futuristic computing power and a lot of time, but the damage is still done and I for one am glad that I wasn’t a subscriber to their service. But perhaps the debacle serves a very good purpose for all of us, in that it affords a much-needed opportunity for a look at the way we do passwords. Continue reading “The Problem With Passwords” →