When I was a child, I “hacked” many electronic devices understanding almost nothing about what they have eaten. In the later age, I studied how to really utilize electronics, as I kept in mind that embedded systems are essential part of the modern world. While I type this text with my laptop, soon you can see it wherever on the globe you are. Seems simple as such, but how about if we peek a little bit deeper. There aren’t many moving parts inside of my computer, but countless numbers of electrons are changing their potential and place in atomic scale; almost at the speed of light! Those electrons stop quite easily when they reach their lowest available energy state, meaning they can be controlled “quite easily”. But it is fascinating that the speed of my processor is amazing 1,730,000,000 Hz! In other words, there is a so called clock in my laptop, electrical potential in a copper, which goes up and down the mentioned times in a second. It gives the rhythm to other components to act synchronously. Why? Well, it would be quite useless if a shorter circuit makes its calculations faster than a bigger one, and if the end products of the two should be combined. The faster one would already calculate something else when the slower one hasn’t even started. And now, please switch your room lights on and off by a controlled manner between every 0.0000000006 seconds; approximately the same speed as the mentioned 1.73 GHz means. Building even a simple, but modern microprocessor, found in a remote control, television or in a microwave oven, is a quite big challenge also otherwise. Not only because of the speed, but the architecture, since the smallest wires in common processors are getting closer and closer to the width of a DNA molecule. Luckily, electronic components are cheap like soap nowadays, and you can buy your very own microprocessor, embedded in a same chip with memory elements and peripherals, for making it to work for you as you want. Together in a same packet these electronic parts are called microcontrollers. Oh, I wish so much that I could already start to build some new project!