Duck And Cover With This WiFi “Geiger Counter”

There’s perhaps no sound more recognizable than the frantic clicking of a Geiger counter. Not because this is some post-apocalyptic world in which everyone is personally acquainted with the operation of said devices, but because it’s such a common effect used in many movies, TV shows, and video games. If somebody hears that noise, even if it doesn’t really make sense in context, they know things are about to get serious.

Capitalizing on this phenomena, [Anton Haidai] has put together a quick hack which turns the ESP8266 into a “Geiger counter” for WiFi. Rather than detecting radiation, the gadget picks up on the strongest nearby WiFi signal and will start clicking in response to signal strength. As the signal gets stronger, so does the clicking. While primarily a novelty, it’s an interesting idea that could potentially be useful for things like fox hunting.

The hardware is really about as simple as it gets, just a basic buzzer attached to one of the digital pins on a NodeMCU development board. This project is more of a proof of concept, but if it were to be developed further it would be interesting to see the electronics placed into a 3D printed replica of one of the old Civil Defense Geiger counters. Perhaps even integrating an analog gauge that can bounce around in response to signal strength.

Software-wise there is the option of locking onto one single network SSID or allowing the device to find the strongest network in the area. Even if you’re not in the market for a chirping WiFi detector, the code is a good example of how you can detect signal RSSI and act on it accordingly; a neat trick which might come in handy in a future project.

If you’re more interested in the real thing, we’ve got plenty of DIY Geiger counters in the archive for you to check out. From diminutive builds that can be mounted to the top of a 9V battery to high-tech solid state versions with touch screen interfaces, you should have plenty of inspiration if you’re looking to kit yourself out before your next drive through the Chernobyl Exclusion Zone.

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Radiation Detector Eschews Tubes, Uses Photodiode

When the topic is radiation detection, thoughts turn naturally to the venerable Geiger-Müller tube. It’s been around for ages, Russian surplus tubes are available for next to nothing, and it’s easy to use. But as a vacuum tube it can be somewhat delicate, and the high voltages needed to run it can be a little on the risky side.

Luckily, there are other ways to see what’s going on in the radioactive world, like this semiconductor radiation detector. [Robert Gawron] built it as a proof-of-concept after having built a few G-M tube detectors before. His solid-state design relies on a reverse-biased photodiode conducting when ionizing radiation hits the P-N junction. The tiny signal is amplified by a pair of low-noise op-amps and output to a BNC connector. The sensor’s analog output is sent to an oscilloscope whose trigger out is connected to a Nucleo board for data acquisition. The Nucleo is in turn connected to a Raspberry Pi for totalizing and logging. It’s a complicated chain, but the sensor appears to work, even detecting alpha emissions from thoriated TIG electrodes, a feat we haven’t been able to replicate with our G-M tube counter.

[Robert]’s solid-state detector might not be optimal, but it has promise. And we have seen PIN diodes used as radiation detectors before, too.

[via Dangerous Prototypes]

A Vacuum Tube and Barbecue Lighter X-Ray Generator

A certain subset of readers will remember a time when common knowledge held that sitting too close to the TV put you in mortal peril. We were warned to stay at least six feet back to avoid the X-rays supposedly pouring forth from the screen. Nobody but our moms believed it, so there we sat, transfixed and mere inches from the Radiation King, working on our tans as we caught up on the latest cartoons. We all grew up mostly OK, so it must have been a hoax.

Or was it? It turns out that getting X-rays from vacuum tubes is possible, at least if this barbecue lighter turned X-ray machine is legit. [GH] built it after playing with some 6J1 rectifier tubes and a 20-kV power supply yanked from an old TV, specifically to generate X-rays. It turned out that applying current between the filament and the plate made a Geiger counter click, so to simplify the build, the big power supply was replaced with the piezoelectric guts from a lighter. That worked too, but not for long — the tube was acting as a capacitor, storing up charge each time the trigger on the lighter was pulled, eventually discharging through and destroying the crystal. A high-voltage diode from a microwave oven in series with the crystal as a snubber fixed the problem, and now X-rays are as easy as lighting a grill.

We have to say we’re a wee bit skeptical here, and would love to see a video of a test. But the principle is sound, and if it works it’d be a great way to test all those homebrew Geiger counters we’ve featured, like this tiny battery-powered one, or this one based on the venerable 555 timer chip.

Global Thermonuclear War: Tweeted

[Andreas Spiess] did a video earlier this year about fallout shelters. So it makes sense now he’s interested in having a Geiger counter connected to the network. He married a prefabricated counter with an ESP32. If it were just that simple, it wouldn’t be very remarkable, but [Andreas] also reverse-engineered the schematic for the counter and discusses the theory of operation, too. You can see the full video, below.

We often think we don’t need a network-connected soldering iron or toaster. However, if you have a radiological event, getting a cell phone alert might actually be useful. Of course, if that event was the start of World War III, you probably aren’t going to get the warning, but a reactor gas release or something similar would probably make this worth the $50.

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Fun-Size Geiger Counter Sits atop a 9-Volt Battery

Want a little heads-up before walking into a potentially dangerous radioactive area? Sure, we all do. But the typical surplus Civil Defense Geiger counter is just too bulky to fit into the sleek, modern every-day carry of the smartphone age. So why not slim down your first line of defense against achieving mutant status with this tiny Geiger counter (Facebook)?

We jest about the use cases for a personal-sized Geiger counter, as [Ian King]’s inspiration for this miniaturized build was based more on a fascination with quantifying the unseen world around us. Details are thin in his post, but [Ian] kindly shared the backstory for this build with us. Working on a budget and mostly with spare parts, the big outlay in the BOM was $20 for a Soviet-era SBM-10 tube, itself a marvel of miniaturization. While waiting the two months needed for the tube to arrive, [Ian] whipped up a perf board circuit with a simple oscillator and a CFL transformer to provide the 400 volts needed for the tube. The whole circuit, complete with tiny speaker and an LED to indicate pulses, sits neatly on top of a 9-volt battery. The video below shows it in action with a test source.

Geiger counters are not exactly rare projects on Hackaday, and with good reason. Take a look at this no-solder scrap bin counter or this traveling GPS Geiger counter built dead-bug style.

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Mood Lamp Also Warns of Nuclear Catastrophe

[Michal Zalewski] has radiation on the brain. Why else would he gut a perfectly-horrible floor lamp, rebuild the entire thing with high-power RGB LEDs, and then drive it with a microcontroller that is connected up to a Geiger-Müller tube? Oh right, because it also looks very cool, and Geiger tubes are awesome.

If you’ve been putting off your own Geiger tube project, and we know you have, [Michal]’s detailed explanation of the driver circuit and building one from scratch should help get you off the couch. Since a Geiger tube needs 400 volts DC, some precautions are necessary here, and [Michal] builds a relatively safe inverter and also details a relatively safe way to test it.

The result is a nice piece of decor that simultaneously warns you of a nuclear disaster by flashing lights like crazy, or (hopefully) just makes a nice conversation piece. This is one of the cooler Geiger tube hacks we’ve seen since [Robert Hart] connected up eighteen Geiger tubes, and used them to detect the direction of incoming cosmic rays and use that to compose random music (YouTube, embedded below).

[Michal] is also author of the most excellent Guerrilla Guide to CNC Machining and keeps good tabs on his background radiation.

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Roam the Wastelands with this Fallout-Themed Mini Geiger Counter

For anyone who has worked with radioactive materials, there’s something that’s oddly comforting about the random clicks of a Geiger counter. And those comforting clicks are exactly why we like this simple pocket Geiger counter.

Another good reason to like [Tim]’s build is the Fallout theme of the case. While not an item from the game, the aesthetic he went for with the 3D-printed case certainly matches the Fallout universe. The counter itself is based on the popular Russian SBT-11A G-M tubes that are floating around eBay these days. You might recall them from coverage of this minimalist Geiger counter, and if you were inspired to buy a few of the tubes, here’s your chance for a more polished build. The case is stuffed with a LiPo pack, HV supply, and a small audio amp to drive the speaker. The video below shows it clicking merrily from a calibration source.

We can see how this project could be easily expanded — a small display that can show the counts per minute would be a great addition. But there’s something about how pocketable this is, and just the clicking alone is enough for us.

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