Quickly identify radioactive materials with a pocket-sized ion chamber. Built from standard parts for easy manufacture and low cost. by Carlos Garcia Saura:
Nuclear radiation is invisible and can be harmful to life. The goal of this project is to provide a simple device that could prevent cases of radiation poisoning. Professional radiation meters can be very accurate, but are also expensive, complex and fragile (most use vacuum discharge tubes made of glass). However in many occasions we only want to determine whether an object is radioactive or not.
Radiation is always present in our lives. We can’t see, taste, feel or smell it, but it exists. Excessive exposure to ionizing radiation may cause potential damage to our health. The new Dosime device helps you to track and understand radiation exposure in your environment and display them using an app on your smartphone.
Dosime is a hybrid smart home and wearable device. The device weighs just 57 grams and is only 6.8 centimeters in height, making it extremely easy to take it with you everywhere. Now, the most important question is, how necessary is it to measure radiation level if someone is not living by a nuclear plant? Well, a nuclear plant is not the only one who emits radiation. 82% of the radiation we are exposed to comes from natural sources. The remaining 18% comes from man-made sources. So, yes. It is necessary to measure radiation level in your environment. On their website the company says:
Healthy living includes managing your environment, including factors you can not perceive. Knowledge of radiation exposure empowers you to make informed decisions about your wellbeing.
The Dosime radiation meter can measure radiation levels up to 100 R/h with a maximum dose of 1000 rem. The range of the measurable energy is 50 keV to 3 MeV. It can detect X-Rays and Gamma (γ) rays, but not Alpha (α) rays and Beta (ß) rays. Unfortunately, they are also sources of harmful ionizing radiation.
The Dosime device seamlessly connects to smartphones via WiFi and Bluetooth Low Energy (BLE). It comes with a built-in rechargeable battery and an AC/DC module. The battery lasts for about one week on a single charge. At home you can dock it in the charger, giving it access to the Wi-Fi network. The app for this device runs on iOS 9 or later, or Android KitKat 4.4 or later.
The Dosime device is available for purchase at a price of US $249.00 (+ $4.81 shipping). You can order it at Amazon.
Geiger counters are devices used to detect radioactive emissions, most commonly beta particles and gamma rays. The counter consists of a tube filled with an inert gas that becomes conductive of electricity when it is impacted by a high-energy particle.
The Geiger–Müller tube or G–M tube is the sensing element of the Geiger counter instrument used for the detection of ionizing radiation.
Biemster wanted to improve this counter to an IoT device connected to the network byusing ESP8266 to discover easily where are the harmful radioactive things around.
Running down the center of the tube there’s a thin metal wire made of tungsten. The wire is connected to a high, positive voltage so there’s a strong electric field between it and the outside tube.
When radiation enters the tube, it causes ionization, splitting gas molecules into ions and electrons. The electrons, being negatively charged, are instantly attracted by the high-voltage positive wire and as they zoom through the tube collide with more gas molecules and produce further ionization. The result is that lots of electrons suddenly arrive at the wire, producing a pulse of electricity that can be measured on a meter, and if the counter is connected to buzzer heard as a “click.” The ions and electrons are quickly absorbed among the billions of gas molecules in the tube so the counter effectively resets itself in a fraction of a second, ready to detect more radiation.
In a nutshell, driving a G-M tube typically consists of 2 distinct parts:
Providing the tube with a high voltage source for it to operate.
Detecting each ionization event and convert it to a format that can be processed and sent over the internet.
Generating high voltage can be done by using PWM (Pulse-Width Modulation) signals after flashing the ESP8266 with the MicroPython firmware (version 1.8.3, with 10 kHz PWM support). Detection can be implemented as an interrupt handler that listens for and acts on discharges in the tube. Each discharge means a new detection.
You will need the following components:
1x STS-5 Geiger tube
1x 4.7 mH inductor
1x 4.7 nF Capacitor
1x KSP44 transistor
1x 2N3904 transistor
1x 1N4007 diode
1x 4.7M resistor
1x 100k resistor
1x 10k resistor
1x 220 ohm resistor
1x optional piezo buzzer
The circuit works as follows: A ~1 Khz squarewave turns the MPSA44 high voltage transistor on and off, generating high voltage when the inductors current is shut off. The voltage depends on the pulse width of the square wave which can be tweaked in software. The 1N4007 diode rectifies this voltage, and the High-Voltage capacitor removes most of the ripple on this voltage. The resistor limits current to the G-M tube. The current pulses from the tube generate a voltage drop over the 100K resistor which turns on the BC546. When this happens the voltage through the 10K resistor is pulled to ground, generating a negative going pulse each time the G-M tube detects an ionizing ray or particle.
The code reports every event over MQTT, the lightweight IoT protocol. It also reports the CPM (Counts per Minute) and the time passed since the previous event as (CPM,dt). The library of this project is available at Github, It handles the low level stuff such as PWM and pin assignments, and a general part that will communicate the measurements out to the world.
For more details, build instructions, and project updates you can follow the project on hackday.
Bob @ robertgawron.blogspot.com has posted a Geiger-Muller project that can be used with Arduino or any other microcontroller board.
The Geiger–Müller counter is a relatively simple tool to measure ionizing radiation. To increase sensitivity, construction presented here contains three (instead of one as usually) soviet STS-5 lamps. This is important for measurements of natural sources of (low) radiation like soil, rocks (an article about my trip with Geiger–Müller counter on Śnieżka mountain).
Geiger–Müller counter that works with Arduino – [Link]
I “rebuild” my Geiger counter, the SBM-20 tube was initially inside the box, i have put this one inside a 32mm diam plastic tube, for more convenience, wired through a XLR3 cable. This counter is from “Electronique-Pratique” n°368, a french electronic magazine. Shem, pcb, and PIC hex & C source code available.