USB Audio Multiplexer

On my desktop PC I have a speakers and a headphones. Usually I use headphones, but when I need to switch to speakers I need to physically plug in speakers instead of headphones to my PC’s soundcard. I wanted to solve this problem for a long time, but never get around of that until recently I saw this posted on Hackaday.

And so I’ve decided to build my own really simple audio multiplexer.

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ATtiny2313 – Based Thermostat Project Update #2

First fully working revision of firmware is finished, which takes all 2k of ATtiny2313′s memory. I wrote it in C, and I wanted to implement some other functionality, but unfortunately I’m out of space(of course if I would want to, I can put there ATtiny4313, which is identical to ATtiny2313, but has 4k of memory). Plus I’ve made a little explanation on temperature hysteresis and thermal capacitance, and ranted about front panel a bit.

UNI-T UT325 Thermometer Teardown

In the review of this thermometer I said that it was a weird Chinese product. And here’s why: despite of the poor firmware and software functionality it has pretty interesting and very “hackable” innards.

Let’s begin..

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UNI-T UT325 Thermometer Review

Very often in electronics you would need to measure temperature, not just in one spot, but simultaneously in two or more spots. And log that measurements, so that you can plot temperature change over time.
Also, differential temperature measurements could be extremely useful in some cases, especially for thermal design of electronic projects.

So, the other day I bought this UNI-T UT325 dual-channel logging thermometer for a little under $80. of another weird Chinese product below..

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PWM Generator Project (part1)

Very often when designing some stuff I need a square wave signal generator with variable pulse width and frequency to control power MOSFETS.

You can use such a tool when designing DC-DC converter or switch-mode power supply, you can use it to emulate PWM from microcontroller when developing some new embedded design, or maybe you want to design your own wireless charger… This is only some of the things you can use it for.

So, I’ve decided to build very simple PWM generator.

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Links To Electronic-Related Websites

Some time ago, after I started adding stuff to EEVBlog wiki page (, I thought why not to make a post about electronic-related websites that I like.
So, here’s my portion of links to electronic-related resources that I find interesting and useful:

Video-Based Blogs:

Text-Based Blogs:

Electronic-Related News And Other Websites:


Datasheet Databases:

Parametric Parts Search:

  • DigiKey – Everybody knows about digikey
  • Mouser – And mouser..

If you know some cool electronic-related websites, blogs, etc – I will be glad to hear about them! I’m always looking for a new information.

P.S. Tomorrow I’ll tell you about project that I started working on.

Break-Beam Sensor

About one month ago I had a request to write about break-beam sensors. So, here it is!

Well, basically break beam sensor consists of two parts: transmitter and receiver. Transmitter emits light (it could be, for example, an LED or a laser) and that light goes to receiver. If that light beam between transmitter and receiver is broken by some obstacle, and receiver detects no incoming light even for a brief moment – it triggers an alarm (or any load you want). For example you can count people that entering some room, or you can use it as an alarm system, yeah, just like in movies!

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ATtiny2313 – Based Thermostat Project (part 3)

ATtiny2313 – Based thermostat project update. I wrote a small test firmware for it to test if everything is wired up the right way and to test it’s current consumption. And it turns out that there were some mistakes..

Also it’s current consumption is well below 150mA that I was expecting.

ATtiny2313 – Based Thermostat Project (part 2)

So I’ve came back to my ATtiny2313 – based thermostat project, that I’ve started to work on some time ago. And today I have assembled a first prototype (actually I only need a couple of these).

If you haven’t seen video I’ve made on this project, you can watch it here: Part1 Video.
It’s based around ATMEL AVR ATtiny2313 microcontroller, it will measure temperature using DS18B20 digital temperature sensor, and it has a 30A 240VAC relay to control heater.

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Complete Soldering Tutorial

In this, rather comprehensive, tutorial I’ll tell you all you need to know about soldering.

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