2015 ~ Robert Gawron

DP-70 dosimeter

in chemistry, radioactivity / with No comments /

DP-70 was a chemical dosimeter used in the Polish army during the Cold War. A dosimeter is a device used to measure the amount of radioactive radiation absorbed by a body, in this case, by soldiers. DP-70 has a form of a small metal cylinder (to protect...

Measuring nuclear-radiation of potassium from cigarette ashes

in chemistry, radioactivity / with 2 comments /

In the previous post I've presented a simple way of extraction compounds from ashes, today I will measure radioactivity of obtained sample by using my homemade Geiger counter. Below is a quick view of the setup that I used. ...

Extracting potassium (with its radioisotope) from cigarette ashes

in chemistry, radioactivity / with No comments /

Organisms are built mainly of carbon, hydrogen and oxygen, but they use many more chemical elements, one of them is potassium. After burning of organic matter, potassium stays in ashes as oxide that later is transformed to hydroxide. In the environment,...

Breadboard made from scrap electronics

in electronic engineering / with No comments /

A simple but useful breadboard can be made at home, it will be more expensive than those on the markets, but it's possible to add commonly used elements, like LEDs, switches, etc. I hadn't had female sockets, so I cut in half old DIP-18 sockets - it...

USB li-ion battery charger

in electronic engineering / with 8 comments /

Li-ion cells become more and more popular due to their capacity and reasonable prices. In this entry I will show how to build a simple li-ion battery charger based on MCP73831 chip. It's a quite useful device for DYI projects,in addition its cost is...

Yet another way protect pictures against copying

in image processing, programming, Python / with 3 comments /

It's not possible to protect an image against any person, but it can be protected enough for most of the users. There are a couple of ways to do this, most popular are CSS tricks, but today I will present another way. Can you save below image? I bet you can't! ;-) .Image2HTMLTable td, tr{ margin:...

Dangling else problem

in C and C plus plus, crappy code, programming / with No comments /

What is a dangling else problem? It's presented below - what will print this program? #include <iostream> int main() { bool a = true; bool b = false; if(a) if (b) std::cout << "foo" << std::endl; else std::cout << "bar" <<...

Tiny and cheap lab generator

in electronic engineering / with 2 comments /

Function generator is a rely useful tool in the lab, a simple version can be build at home, there's a lot of examples on the Internet, some are much more complex and powerful, but this one is intended to be really simple and cheap. It can be also built-in...

A trip with Geiger Counter on the Śnieżka mountain

in C and C plus plus, programming, radioactivity / with 1 comment /

During the Second World War Nazis established a uranium mine in Krkonoše mountains. Extracted ore was used in a research facility in Oranienburg. After the war, the mine was in polish borders, but Poland was then a puppy country of the USSR, so the ore...

ATtiny44 evaluation board for DYI robots

in C and C plus plus, electronic engineering, programming / with 2 comments /

Intro I will start from saying that the board could be replaced by any Arduino plus some(s) its motor driver shield(s). So why I made it you may ask? Well, while I made this tiny tank-robot model presented on below pictures, I wanted to make at least...

DKP-50 dosimeter (radioactivity detector) tear-down

in electronic engineering, radioactivity / with 7 comments /

DKP-50 was a dosimeter produced for the Polish People's Army during the cold war era. It indicates amount of radioactivity absorbed by the body, a soldier was equipped in this device in case of nuclear conflict. A scale has range of 0-50R (R = Roentgen,...

Kirlian photography - electronic engineering meets parapsychology

in electronic engineering, high voltage, image processing, parapsychology / with 2 comments /

Kirlian photography is an interesting photographic technique of capturing corona discharge of objects. The images basically contain only edges in a form of blue glow. Note: one of those photos is visible in "The X files" intro - read the whole article...

Modular DIY Geiger–Müller counter

in electronic engineering, high voltage, programming, radioactivity / with 15 comments /

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...

Deobfuscation JavaScript code - how to start?

in Haskell, programming / with 1 comment /

The easiest way to obfuscate code is to remove white-spaces that are not necessary and to shorten the names of variables and functions. A couple of years ago a made this simple tool to parse such obfuscated JavaScript code. An example how the code can look after obfuscation and before passing it to...

USB powered thermometer with an interesting data display

in C and C plus plus, electronic engineering, programming / with 2 comments /

Almost each person interested in building electronic devices has built at least one thermometer and power supply in his life. I'm not different, to add to this, today I will present one of my thermometers. Original concept was different, I wanted...

Popularne pytania z rozmów wstępnych dla programisty C/C++

in C and C plus plus, programming, work / with 1 comment /

W tym wpisie podzielę się zbiorem pytań, które często powtarzają się na różnych rozmowach wstępnych na stanowisko programisty C/C++. Są to pytania techniczne - nie opisałem tu żadnych pytań miękkich (HR'owych). Spotkałem się z nimi sam (już prawie 10 lat pracy, jak ten czas leci..), a niektóre zadawałem...