ESP32 Brings New Features To Classic Geiger Circuit

June 24, 2024 by Tom Nardi 4 Comments

There’s no shortage of Geiger counter projects based on the old Soviet SBM-20 tube, it’s a classic circuit that’s easy enough even for a beginner to implement — so long as they don’t get bitten by the 400 volts going into the tube, that is. Toss in a microcontroller, and not only does that circuit get even easier to put together and tweak, but now the features and capabilities of the device are only limited by how much code you want to write.

Luckily for us, [Omar Khorshid] isn’t afraid of wrangling some 0s and 1s, and the result is the OpenRad project. In terms of hardware, it’s the standard SBM-20 circuit augmented with a LILYGO ESP32 development board that includes a TFT display. But where this one really shines is the firmware.

With the addition of a few hardware buttons, [Omar] was able to put together a very capable interface that runs locally on the device itself. In addition, the ESP32 serves up a web page that provides some impressive real-time data visualizations. It will even publish its data via MQTT if you want to plug it into your home automation system or other platform.

Between the project’s Hackaday.io page and GitHub repository, [Omar] has done a fantastic job of documenting the project so that others can recreate it. That includes providing the schematics, KiCad files, and Gerbers necessary to not only get the boards produced and assembled, but modified should you want to adapt the base OpenRad design.

This project reminds us of the uRADMonitor, which [Radu Motisan] first introduced in 2014 to bring radiation measuring to the masses. This sort of hardware has become far more accessible over the last decade, bringing the dream of a globally distributed citizen-operated network of radiation and environmental monitors much closer to reality.

Continue reading “ESP32 Brings New Features To Classic Geiger Circuit” →

An Open Source Firmware For Cheap Geiger Counters

June 24, 2023 by Al Williams 11 Comments

It is a time-honored tradition: buy some cheap piece of gear and rewrite the firmware to make it work better. [Gissio] managed to do just that for a cheap FS2011 Geiger counter. Apparently, the firmware will also work with some similar Chinese models, too.

The new firmware boasts an improved UI and multiple measurement units, including Sievert, Rem, and counts per minute or second. You can hold the measurement or compute a dose or average rate. The new firmware also has a host of customizations and can accommodate different tubes.

There are, however, two really key features. First, the new firmware offers about 40% more battery life than the stock version. Second, there is now an onboard nuclear chess game! That way, you can enjoy yourself while you are getting irradiated. There are also a few suggested hardware mods that are optional to improve measurements and increase the buzzer volume, among other things.

If you get a Geiger counter, you might be surprised at what things are slightly radioactive. If you don’t need the microcontroller, you can make a workable counter on the cheap.

Continue reading “An Open Source Firmware For Cheap Geiger Counters” →

Detecting Radiation For Fun And Profit

November 9, 2022 by Al Williams 19 Comments

It used to be that every well-stocked doomsday bunker had a Geiger counter. These days, you don’t have to have a big tube-based meter. You can inexpensively get a compact digital instrument to handle your radiation detection needs. [DiodeGoneWild] reviews and tears down such a unit from FNIRSI. The case looks like several other similar instruments we’ve seen lately, so presumably, someone is mass-producing these handheld meter cases. You can see the video, below. The meter reads the absolute radioactivity and can also measure cumulative exposure.

After measuring a few common radioactive items, we get to the teardown. Inside, of course, is an ordinary tube. A few screws reveal a typical rechargeable battery, a fairly simple PCB with a microcontroller and battery backup for the real-time clock. A lot of the board is involved in multiplying voltage up to the several hundred volts required for the Geiger tube.

The other side of the PCB has only buttons, a vibration motor, and, of course, the LCD. We don’t know how you might test the relative accuracy other than comparing it to a known-good meter. The bare tube was, of course, more sensitive without the plastic cover, but that could be calibrated out, too.

A Geiger counter doesn’t have to have a lot of parts. Either way, a surprising number of things will set them off.

Continue reading “Detecting Radiation For Fun And Profit” →

A black PCB with an ESP32 and an SBM-20 geiger counter

Flexible Radiation Monitoring System Speaks LoRa And WiFi

September 10, 2022 by Robin Kearey 12 Comments

Radioactivity has always been a fascinating phenomenon for anyone interested in physics, and as a result we’ve featured many radioactivity-related projects on these pages over the years. More recently however, fears of nuclear disaster have prompted many hackers to look into environmental radiation monitoring. [Malte] was one of those looking to upgrade the radiation monitor on his weather station, but found the options for wireless geiger counters a bit limited.

So he decided to build himself his own Wifi and LoRa compatible environmental radiation monitor. Like most such projects it’s based on the ubiquitous Soviet-made SBM-20 GM tube, although the design also supports the Chinese J305βγ model. In either case, the tube’s operating voltage is generated by a discrete-transistor based oscillator which boosts the board’s 5 V supply to around 400 V with the help of an inductor and a voltage multiplier.

Graphs showing temperature, humidity and radiation levels — Data can be visualized in graphs, together with other data from the weather station like temperature and humidity

The tube’s output signal is converted into clean digital pulses to be counted by either an ESP32 or a Moteino R6, depending on the choice of wireless protocol. The ESP can make its data available through a web interface using its WiFi interface, while the Moteino can communicate through LoRa and sends out its data using MQTT. The resulting data is a counts-per-minute value which can be converted into an equivalent dose in Sievert using a simple conversion formula.

All design files are available on [Malte]’s website, including a PCB layout that neatly fits inside standard waterproof enclosures. Getting more radiation monitors out in the field can only be a good thing, as we found out when we tried to detect a radiation accident using community-sourced data back in 2019. Don’t like WiFi or LoRa? There’s plenty of other ways to connect your GM tubes to the internet.

ESP32 Powers Fresh Take On An IoT Geiger Counter

July 7, 2022 by Tom Nardi 17 Comments

Over the years we’ve covered many projects aimed at detecting elevated radiation levels, and a fair number of them have been Internet connected in some way. But as they are often built around the Soviet-era SBM-20 Geiger–Müller tube, these devices have generally adhered to a fairly conservative design. With the current situation in Europe heightening concerns over potential radiation exposure, [g3gg0] thought it was a good a time as any to revisit the idea of an Internet-connected Geiger counter using more modern components.

Now to be clear, even this modernized approach still makes use of that same SBM-20 tube. There’s such an incredible wealth of information floating around out there about how to work with them that you’d almost put yourself at a disadvantage to chose something else to base your design on. Put simply, it’s hard to go wrong with a classic.

An unfortunate bug was discovered in the HV circuit.

That said, [g3gg0] decided early on that the design would use as many SMD components as possible, a considerable departure from many of the SBM-20 counters we’ve seen. That meant coming up with a new high-voltage power supply capable of providing the tube with the necessary 400 V, which from the sound of things, took a few attempts to complete. The final result is perhaps the smallest and cleanest looking board we’ve ever seen play host to this particular tube.

To run the show, [g3gg0] selected the ESP32-PICO-D4. You certainly don’t need such a powerful microcontroller to read the impulses from the SBM-20 tube and publish them via MQTT, but to be fair, the chip has a number of other duties. It’s handling the WS2812 RGB LEDs that go off in response to detected particles, running the (apparently optional) 2.9 inch WaveShare electronic paper display, and also pulling data from a BME280 environmental sensor as well as a CCS811 VOC sensor — so it’s keeping fairly busy.

As impressive as this build is, we do hate that it had to be built. From certain world leaders dropping casual comments about the strength of their nuclear arsenal to foolhardy attempts to capture the Chernobyl power station, having access to a reliable Geiger counter isn’t an unreasonable precaution right now. For everyone’s sake, let’s hope the fancy RGB LEDs on this particular build remain as dark as possible.

Continue reading “ESP32 Powers Fresh Take On An IoT Geiger Counter” →

Is Your Tape Dispenser Radioactive?

March 11, 2022 by Al Williams 26 Comments

Do you have anything radioactive in your house? Most people will say no, but they are probably wrong. A host of things ranging from glow-in-the dark timepieces to smoke detectors have some amount of radioactivity. But as [Wheeler Scientific] points out, so do some old Scotch tape dispensers. You can watch the video, below.

The dispenser in question is the C-15 which was very common around offices, military bases, and homes for years. They were made up until the 1980s. You have to wonder why a tape dispenser would be radioactive, and [Wheeler] has the explanation.

When you pull tape from the dispenser, you don’t want the dispenser to slide around the desk, so it needs to be heavy. But no one wants to have a giant dispenser nor do you want to pay for one made from a dense metal. So the plastic dispenser contains a ballast to make it heavier. In the case of the C-15 that ballast is thorium-containing monazite sand. A vintage counter shows the radioactivity which isn’t much, of course, but still way less than the ordinary sand used in newer models. You can also see in the video that the material is paramagnetic.

Monazite used to be a primary source of lanthanides but getting rid of the thorium led to alternate sources in the 1960s although it is still used as an ore for thorium. We know some lenses are radioactive. If you want to search your home for radioactivity and you don’t have a Geiger counter, you don’t need much to build one.

Continue reading “Is Your Tape Dispenser Radioactive?” →

Civil Defense Disco Ball Rocks Ground Zero

January 15, 2021 by Tom Nardi 9 Comments

Old Civil Defense survey meters like the V-715 are interesting conversation starters, but of very little practical use today. These devices were intended to be a sort of litmus test that survivors of a nuclear blast could use to determine when it was safe to venture out of their radiation shelter: if the needle on the meter moves, even when it’s on the most sensitive setting, you should probably go back inside. Since [Hamilton Karl] would (hopefully) never need such an indicator, he decided to have a little fun with this Cold War holdover and turn it into a Disco Containment Unit.

Technical details are a little sparse on this one, but we can infer most of it just from the pictures. In place of the original meter [Hamilton] has mounted a tiny mirrored ball inside of a protective cage, which is spun by a geared motor that’s occupying the space that used to be taken up by the ion chamber.

A handful of Adafruit NeoPixel RGB LEDs, an Arduino Nano, and a few switches to control it all round out the functional aspects of the build, and a new disco-themed trefoil replaces the original Civil Defense logo on the side. The project page mentions there’s a piezo buzzer onboard that performs a stirring rendition of “Stayin’ Alive” by the Bee Gees, but alas there’s no video that shows it in action.

Thanks to the rugged construction and built-in handle of these old survey meters, [Hamilton] can now take the party with him wherever he goes. Not that he can really go anywhere with this whole global pandemic hanging over our heads, but at least he’ll be ready when things start trending towards normal. In a way the device’s functionality has now been reversed from how it originally worked, since the meter going wild will now be an indicator that its safe to come out.

While the V-715 isn’t of much use outside of a post-apocalyptic hellscape, the V-700 is actually a proper Geiger counter that’s still useful for surveying or research. An important distinction to remember if you ever get a chance to snap one of them up at a swap meet or flea market. Whenever we can start having those again, anyway.