Archive for July, 2013

Arduino (any microcontroller) as a variable capacitor

I’m working on an micro-controller driven variable capacitor, here’s some video:



Electronics as a hobby by a lazy blog maintainer

I’ve been very busy with electronics lately, so busy that I forgot my password for this blog!

Before this post, probably a year ago, I was experimenting with charlieplexing. Not much after, I somehow started to get entangled in radio oriented electronics.

I knew I wanted to learn more about analog circuits and the limitless theory that lurks behind it. I decided to build my own radio receiver. What I didn’t realize was that this was going to be one of the hardest learning paths I’d encountered yet. Bare in mind that I had just barely understood what a voltage divider was and had no practical understanding of common components, like a transistor.

This post is an attempt at explaining the do’s and don’ts about electronics design from the perspective of a novice with about 1.5 years experience.

My first etched PCB

My first etched PCB

Learn how to experiment

I spent countless of hours playing around with resistor values without even understanding what results I wanted. It’s crucial to know what you are aiming to achieve, even if you do some minor poking. Last Autumn I wasted a lot of time while trying to build radios, none of them really worked. Even if you are a beginner at something and more importantly if you are learning alone, make a detailed plan of what you want to achieve and be proud of it. To me  electronics usually feels like voodoo magic (isn’t it?), but then when I tackle all the mysteries step by step, without being too ambitious, things start to make sense. Hence, to truly benefit from experimentation, you need to understand all the concepts you are dealing with. First build a simple design by someone else, study it, and then tweak it.

Have the right equipment

If you are going to design something, you need to have both the right tools and materials to do so. You need to decide early enough, how serious you are about your project and what you need to procure in order to complete it. It doesn’t mean that you need all the gear in the world. I wanted to build an radio and it didn’t take long for me to realize that I couldn’t do it without an oscilloscope, so I bought one second hand. Alas, I wasn’t blind anymore, suddenly I could play around with oscillators and actually see something happening. The point isn’t that you should buy an oscilloscope, but that for certain situations you just need to have some specific equipment at hand. For example, if you’re going to do something with electronics, you definitely need an multimeter. In addition, understand the components you’re going to need for your project and buy them! Dont try to reinvent the wheel by trying to play around with a limited set of parts to achieve amazing results. I tried to make variable capacitors out of cardboard and aluminum foil, guess what, it didn’t really work. Sure it was fun, but it was much funner with a proper variable air capacitor. When you have the right equipment, materials and knowledge, you can even design your own tools. But you have to start somewhere.

Regenerative receiver in an old PSU case

Regenerative receiver in an old PSU case


There is nothing more rewarding than reaching a set goal. Complicated projects require many steps, but if laid out correctly, each one is surprisingly simple. Now only if I ever learned to document my work properly!


Write comments if you have something you need to ask.

Current OS:

Arch Linux / Windows 7