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The debate of whether or not to install your own surround sound system has fallen on deaf ears and you have decided to tackle this delicate task for yourself. Good for you. The thing is you aren't really too certain about where to actually begin this delicate procedure. At this point, I'm assuming that you have purchased either a home theater kit or surround sound system for your home and are preparing to begin the actual installation process. A good place to start is by reading the instructions and owners manual that most likely came with either the kit you purchased or each of the individual components. The thing to remember with a  surround sound   system is that nothing will work without the speakers and they will only work for their intended purpose if they are positioned properly. However, you need to make sure that the other components are in place before beginning to work with the speakers. I recommend, particularly if this is your first system that you go with a...

I recently bought a little electric guitar for my daughter. It had a few issues (more on that in a future post), but all in all it’s a decent enough instrument. I wanted to build her a small portable amp to go with it, and this one, based on a TDA7052 audio power amplifier, came recommended: http://www.redcircuits.com/Page96.htm It’s a very simple, compact circuit, and theoretically you can fit it into a cigarette packet. However, I was happy enough to fit it into a plastic box, which allowed me to use a slightly larger speaker and also not have to worry so much about cramming everything into a tiny space. I also left out J2 (the output jack), since I have no intention of connecting this to a larger amplifier. Here’s the box, speaker, speaker grill (actually, it’s a fan grill from a computer, since I couldn’t find a suitable speaker cover), jack and veroboard. First we drill (well, bore) a large hole for the speaker in the lid. Centring the hole: Boring: This is how it turned out, stil...

Stepper motors are brushless DC motors which can move in discrete steps thanks to the special coil arrangement inside. They are very popular in DIY and industry projects which require accurate mechanical movement control. In this SoloPCB project, we are building a dual stepper motor driver shield based on two Allegro A4988 ICs which can supply up to 35V and 2A and provide overcurrent and thermal protection. [ ]

Hard water has a high concentration of minerals, and of these calcium salts are the most troublesome. But there is a solution coming in form of a cheap diy water softener system built with the well-known 555 IC. Actually the price of this diy system is so low that even if this doesn’t work you won’t be upset. The working principle of the water softener is based on a theory from 1930 which states that an electromagnetic or electric field causes small crystals of calcium carbonate in the water to join together to form larger crystals. One of the methods to obtain a strong magnetic field is to put a powerful magnet (2.5 gauss) near the water pipe. The second method is the electronic one. Studying a water filter purchased from stores we found that it produces a frequency of about 15 kHz at an amplitude of 15V. Water Softener Circuit Schematic cheap diy water softener system circuit schematic Extension: water softener power indicator The values of the coils are not known, but my guess is L1...