A Cheap, 555-Based Geiger Counter

October 16, 2016 by 37 Comments

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.

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LED Matrix Plus Geiger Counter

May 25, 2015 by 10 Comments

A lot of projects get made because someone just has the parts lying around. In this case, [Ed Nisley] got given a nice 8×8 RGB LED matrix, and needed something to display. [Ed] details the transformation of stuff-lying-on-the-desk into a unique matrix display for a Geiger counter (which he also presumably had sitting around somewhere). The result is a lightshow that’s as random as radioactive decay, and that’s pretty darn random.

img_5583-random-led-dots-circuit-layout-rb-smd-resistorsThe first post covers the hardware layout. It’s build on protoboard, but ends up looking a lot nicer than our projects because [Ed] spent some time hiding the shift-register ICs and row-driver transistors underneath the matrix itself, which was nicely socketed above. A sweet touch is the use of SMT resistors soldered upright underneath the board to save space. Cute.

The second post covers the circuit design, and is worth a look if you’re new to driving many LEDs from a minimum number of microcontroller pins. There are eight rows, and three colors each for eight LEDs per row. Without using shift registers, this would require 8*8*8*8 = way too many pins to control. If you want a worked example of how to do this with just four microcontroller pins, have a look. (Spoiler: cascaded shift registers driven by the AVR’s hardware SPI peripheral.)

The third post starts to flesh out the software. [Ed] settled on seven colors (and off) for the display, so the matrix’s total state can be crammed into just 32 bytes, which fits nicely in even a tiny microcontroller, much less the gargantuan ATmega328. Wrapping this all up in an array of structs and providing a couple of helper functions makes quick work of the software side. The addition of a sync pulse to trigger an oscilloscope at the end of a row is a nice touch.

aware-rm-60-geiger-pulseNext up is the Geiger counter interface software post. When a radioactive decay event is detected, the code reads out the time in milliseconds and uses that as the source of randomness. To whiten the noise, the times are run through a simple hash function: the Jenkins hash (link). This hash function was new to us and seems pretty useful for quick-and-dirty microcontroller applications.

The last post details pre-loading the matrix on startup and running a test sequence that blinks each LED to make sure they’re all working. Using a single random value to seed a software pseudo-random number generator ensures that it will (almost) never start off with the same display twice.

Phswew! That’s a lot of well-documented writeup of a well-polished project! Hope it inspires you to dig out something cool from your junk drawer and build.

A Deadbugged GPS/GLONASS/Geiger Counter

April 26, 2015 by 38 Comments

So you think you’re pretty good at soldering really tiny parts onto a PCB? You’re probably not as good as [Shibata] who made a GPS/GLONASS and Geiger counter mashup deadbug-style with tiny 0402-sized parts.

The device uses an extremely small GPS/GLONASS receiver, an AVR ATxmega128D3 microcontroller, a standard Nokia phone display and an interesting Geiger tube with a mica window to track its location and the current level of radiation. The idea behind this project isn’t really that remarkable; the astonishing thing is the way this project is put together. It’s held together with either skill or prayer, with tiny bits of magnet wire replacing what would normally be PCB traces, and individual components making up the entire circuit.

While there isn’t much detail on what’s actually going on in this mess of solder, hot glue, and wire, the circuit is certainly interesting. Somehow, [Shibata] is generating the high voltage for the Geiger tube and has come up with a really great way of displaying all the relevant information on the display. It’s a great project that approaches masterpiece territory with some crazy soldering skills.

Thanks [Danny] for sending this one in.

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Use A Cheap PIN Diode As A Geiger Counter

October 25, 2014 by 50 Comments

After the Fukushima nuclear power plant disaster, radiation measurement became newly relevant for a lot of people. Geiger-Müller tubes, previously a curiosity, became simultaneously important and scarce.

Opengeiger.de (English-language version here) has complete instructions for making a Geiger counter without a Geiger-Müller tube. Instead, this counter uses a PIN photodiode and some carefully chosen operational amplifiers. The total cost of such a device is significantly cheaper than the alternative: under $1 for the diode and around $5 for the rest. And since the PIN photodiode in question is used in many other devices, it’s not a niche component like a Geiger tube is.

The secret sauce is in component selection and tuning. Opengeiger uses the BPW34 diode because it is relatively common and has a large surface area, but also because it has a very low capacitance when reverse-biased. The first-stage opamp choice is also fairly critical. Considering that an average gamma radiation event produces only around 10 nanoamps for about 50 microseconds, a lot of amplification (100,000x), low noise, and high bandwidth are a must.

If you want to get started with this project, you could first browse through the explanation (PDF) to get an overview of the project’s goals, read up on all the technical considerations (PDF) or just head straight for the DIY instructions for the “Stuttgarter Geigerle” (PDF, schematic is on the last page). All of the documentation is chock-full of relevant references and totally worth the read.

A Geiger Counter For An Off-Road Apocalypse Vehicle

August 24, 2014 by 33 Comments

prog2

If the world comes to an end, it’s good to be prepared. And let’s say that the apocalypse is triggered by a series of nuclear explosions. If that is the case, then having a Geiger counter is a must, plus having a nice transport vehicle would be helpful too. So [Kristian] combined the two ideas and created his own Geiger counter for automotive use just on the off chance that he might need it one day.

It all started with a homemade counter that was fashioned together. Then a display module with a built-in graphics controller that was implemented to show all kinds of information in the vehicle. This was done using a couple of optocouplers as inputs. In addition, a CAN bus interface was put in place. As an earlier post suggests, the display circuit was based on a Microchip 18F4680 microcontroller. After that, things kind of got a little out of control and the counter evolved into more of a mobile communications center; mostly just because [Kristian] wanted to learn how those systems worked. Sounds like a fun learning experience! Later the CPU and gauge was redesigned to use low-quiescent regulators. A filtering board was also made that could kill transients and noise if needed.

The full project can be seen on [Kristian]’s blog.

A Touch Screen Geiger Counter Without A Geiger Tube

September 14, 2013 by 33 Comments

geiger

We’re assuming [Toumal] was desperately bored one day, because in the depths of the Internet he found some really cool components to build a solid state Geiger counter.

The Arduino and touchscreen are rather standard fare [Toumal] picked up on eBay for about $30. What really sets this project apart from all the other geiger counter builds we’ve seen is the solid state geiger counter [Toumal] used. This device uses a specially-made photodiode made by First Sensor to detect gamma emissions from 5 to 1000 keV.

[Toumal] put all the software for his Arduino touch screen radiation detector up on github. To be honest, we’re really impressed with the rad sensor [Toumal] used for this project, so if you ever decide to pick one of those up, he’s got your back with an Arduino library for it.

3D Printed Pip-Boy, Geiger Counter Not Included

July 1, 2013 by 27 Comments

pip

Yes, we all love portal guns and crowbars, but there’s one piece of video game paraphernalia that could conceivably be a useful piece of hardware for the modern technologist. It’s the Pip-Boy 3000, the wrist-wearable computer from Fallout, and now you can print on on your 3D printer.

All the pieces for this Pip-Boy are available over on Thingiverse. Included in those files are a dozen plastic parts that, when assembled, come together to form a wrist-mounted computer. You could, of course, print out a static image of a Pip-Boy screen for this build, but [dragonator] made a little addition to his model – he put in a space for a smartphone, so all your environmental sensors and inventory management also work with this 3D printed model.

This is far from the first wearable Pip-Boy we’ve seen, but it is the first that’s able to be fabricated on a 3D printer, and comes with the nice bonus of being the best phone case ever. It’s still a lot of work to put this together, but we’re going to say the results are fantastic.

You can check out the demo video of the Pip-Boy below.

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