Soviet Era Smoke Detector Torn Down, Revealing Plutonium

It’s widely known that a smoke detector is a good ionizing radiation source, as they contain a small amount of americium-241, a side product of nuclear reactors. But what about other sources? [Carl Willis] got hold of an old Soviet era smoke detector and decided to tear it down and see what was inside. This, as he found out, isn’t something you should do lightly, as the one he used ended up containing an interesting mix of radioactive materials, including small amounts of plutonium-239, uranium-237, neptunium-237 and a selection of others. In true hacker fashion, he detected these with a gamma ray spectroscope he has in his spare bedroom, shielded from other sources with lead bricks and copper and tin sheets. Continue reading “Soviet Era Smoke Detector Torn Down, Revealing Plutonium”

A Cheap, 555-Based Geiger Counter

Every mad scientist’s lair needs a Geiger counter. After all, if that UFO crashes on the back patio, you might need to know if it is hot. [Tanner_Tech] shows you how to build a cheap one that will get the job done.

You do need a Geiger tube, but a quick search of a popular auction site shows plenty of Russian surplus for a few bucks. The other thing you need is a source of high voltage (about 400V), which is the heart of the circuit using a 555-based DC to DC converter. You can see a video of the device working, below.

The DC to DC converter needs a transformer that [Tanner] swiped out of an alarm clock. A piezo transducer (stolen from a junk microwave) gives you the characteristic click. If you prefer solid state over hollow state, there’s an open source project that uses a PIN diode as a sensor. Or you could add an Arduino and some LEDs.

Continue reading “A Cheap, 555-Based Geiger Counter”

Air Quality Surveillance for Whole Cities

Air quality is becoming a major issue these days, and not just for cities like Beijing and Los Angeles. It’s important for health, our environment, and our economy no matter where we live. To that end, [Radu] has been working on air quality monitors that will be widely deployed in order to give a high-resolution air quality picture, and he’s starting in his home city of Timisoara, Romania.

[Radu] built a similar device to measure background radiation (a 2014 Hackaday Prize Semifinalist), and another to measure air quality in several ways (a 2015 Hackaday Prize Finalist and a Best Product Finalist; winners will be announced next weekend). He is using the platforms as models for his new meter. The device will use a VOC air sensor and an optical dust sensor in a mobile unit connected to a car to gather data, and from that a heat map of air quality will be generated. There are also sensors for temperature, pressure, humidity, and background radiation. The backbone of the project is a smart phone which will upload the data to a server.

We’ve seen other air quality meters before as well, and even ones based around the Raspberry Pi,  but this one has a much broader range of data that it is acquiring. Its ability to be implemented as an array of sensors to gather data for an entire city is impressive as well. We can envision sensor networks installed on public transportation but to get to all parts of every neighborhood it would be interesting to team up with the Google Streetview Cars, Uber, or UPS.

Earth Day: Environmental Sensors

Before you attempt to solve a problem, you must first study the problem. If there’s a problem with the environment, you must therefore study the environment at a scale never seen before. For this year’s Hackaday Prize, there are a lot of projects that aim to do just that. Here are a few of them:

[Pure Engineering]’s C12666 Micro Spectrometer has applications ranging from detecting if fruit is ripe, telling you to put sunscreen on, to detecting oil spills. Like the title says, it’s based on the Hamamatsu C12666MA spectrometer, a very tiny MEMS spectrometer that can sort light by wavelength from 340 to 780nm.

The project is to build a proper breakout board for this spectrometer. The best technologies are enabling technologies, and we can’t wait to see all the cool stuff that’s made with this sensor.

[radu.motisan]’s portable environmental monitor isn’t just one sensor, but an entire suite of them. The design of the project includes toxic and flammable gas sensors, radiation detectors, dust sensors, and radiation detectors packaged together in a neat, convenient package.

[radu] has already seen some success with environmental sensors and The Hackaday Prize; last year, his entry, the uRADMonitor placed in the top fifty for creating a global network of radiation sensors.


Global Radiation Monitoring Network Update

Things have been busy at Global Radiation Monitoring Network Central Command. As a semifinalist in the Hackaday Prize, project creator [Radu Motisan] has quite a bit of work to do. He’s not slacking off either. With 33 project logs (and counting), [Radu] has been keeping us up to date with his monitoring network and progress on uRADMonitor , the actual monitoring hardware.

[Radu’s] latest news is that he’s ready to go into production with model A of the uRADMonitor. Moving from project to production can be an incredible amount of work due to sourcing parts, setting up assembly houses, and dealing with any snags that come up along the way. We’re sure [Radu] can handle it, though.

The network of uRADMonitors is also growing. A new monitor was just installed in Prescott, Arizona. This is the 10th unit in the USA.  You can view the map, data, and graphs of global radiation live on the uRADMonitor website.

SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize.

THP Hacker Bio: radu.motisan


Here’s a great example of thinking big while keeping it simple. [Radu Motisan‘s] putting together a global radiation monitoring network as his entry in The Hackaday Prize.

The simplicity comes in the silver box pictured above. This houses the Geiger tube which measures radiation levels. The box does three things: hangs on a wall somewhere, plugs into Ethernet and power, and reports measurements so that the data can be combined with info from all other functioning units.

After seeing the idea we wanted to know more about [Radu]. His answers to our slate of queries are found below.

Continue reading “THP Hacker Bio: radu.motisan”

Improving A Homebrew CT Scanner With Barium


[Peter] has been working on his homebrew CT scanner for a while, and it’s finally become something more than a spinning torus of plywood. He’s managed to image the inside of a few pieces of produce using an off-the-shelf radiation detector and a radioactive barium source

When we last saw [Peter]’s CT scanner, he had finished the mechanical and electronic part of the Stargate-like device, but the radioactive source was still out of reach. He had initially planned on using either cadmium 109 or barium 133. Both of these presented a few problems for the CT scanner.

The sensor [Peter] is a silicon photodiode high energy particle detector from Radiation Watch this detector was calibrated for cesium with a detection threshold of around 80keV. This just wasn’t sensitive enough to detect 22keV emissions from Cd109, but a small add-on board to the sensor can recalibrate the threshold of the sensor down to the noise floor.

Still, cadmium 109 just wasn’t giving [Peter] the results he wanted, resulting in a switch to barium 133. This was a much hotter source (but still negligible in the grand scheme of radioactivity) that allowed for a much better signal to noise ratio and shorter scans.

With a good source, [Peter] started to acquire some data on the internals of some fruit around his house. It’s still a slow process with very low resolution – the avocado in the pic above has 5mm resolution with an acquisition time of over an hour – but the whole thing works, imaging the internal structure of a bell pepper surprisingly well.