tamilkamathaigal

Project Features Automatically resets a crashed, frozen Linux PC Simple Uses a cheap USB-to-serial adapter Introduction For several years I have been using a MythTV Linux server to record television shows. It works very well and I like it a lot. It has one major problem though: Sometimes it locks up. I suspect that this happens when it changes channels and signals are weak (e.g. due

Introduction Halloween is a rather new tradition in our part of the world, but my family is very enthusiastic about it. Tombstones are built, bones are scattered in our front garden and a fog machine is kept in the basement for just this one day of the year. This time I thought that I could contribute a little LED effect. My idea was to use a couple of red LEDs to create a red-glowing eye

Putting it all together In part 1 and part 2 of this posts I investigated and designed the components for a solar-powered Morse thermometer. In part 3 everything gets connected. In order to get the most out of the collected sunlight it is important to use as little power as possible. A red LED is a good choice here, because it only has a forward voltage of 1.7 Volts. So it will consume only

Project Features Simple Cheap Doesn't take long Can be done by children (with a little help) Introduction One of my sons recently started to nag me. He wanted to solder something. Initially I had no idea what he could solder and I thought he was simply bored. But he kept going and I knew I had to find something. Finally I remembered that it would be "Blue Night" soon and that I

The transistor as current sourceIn part 3 of this tutorial we looked briefly at several current sources, which contain integrated circuits. In this part, we will look in more detail at a simple current source built from a transistor, a zener diode and two resistors. The basic principle for this circuit is to start with a fixed reference voltage. This voltage is then translated to a fixed

Actively Stabilizing the Current In part 2 of this tutorial we found that there are situations, when a simple resistor is not good enough to keep the current through an LED stable. There are countless ways to stabilise the electrical current actively. Some are simple, some are complicated. I will show a few here. Note: The LED in the following schematics generates red light and has a

Resistance is not futile... Part 1 of this tutorial showed why using an LED is not as straight forward as using a light bulb. Now we have a look at different ways to operate an LED. The simplest and well known way to operate an LED is to add a series resistor. It is quite easy to determine the value for this resistor: Start with the operating point of the LED. E.g. an LED might have a

Introduction LEDs are just great. Nowadays they are cheap, durable and power efficient. You get them in all colours, shapes and sizes. But along with all the advantages comes a disadvantage, too. LEDs have special demands when it comes to their power supply. In most cases, this is not too bad. But many beginners in electronics have problems to understand those requirements. With this post I

Project Features Extremely simple hardware Low-Cost Uses the internal temperature sensor of the ATtiny25 Introduction I used to have one of those electronic thermometers with an outdoor sensor. That sensor transmits its readings through an RF link. Except that it didn't really work. Every now and then I had to reset the thermometer so that it would re-connect to the sensor. This

Project Features Simple Cheap Doesn't take long Can be done by children (with a little help) Introduction When I was working on one of my projects recently, my 8-year-old son came along and wanted to "help me". I was working on something really complicated and there was no way I would let him meddle with it. On the other hand I wanted to take the opportunity to show him that

Electronics design in my opinion is the art of finding the best compromise. And this can be quite a complex art. There are many different and sometimes contradicting requirements to a project: Cost, time, space, weight, power, technology, market, availability of materials and tools, knowledge. This is why the all singing all dancing solution isn't always a good solution. Sometimes less is more.

OK, this one isn't really a project. But I wanted to share it anyway. One day a bought this little ...light thingy in a junk shop. I didn't really know what it was, but it had LEDs and anyway it was only 1 €... This is what it looks like: It turns out that it has three very bright LEDs in red, green and blue and it works in different modes; one of them is a colour change mode. But it does this