Wednesday, November 26, 2014

Eggs in a microwave oven

An attempt to cook eggs in a microwave oven.


  • Grease cup with cooking oil
  • Break 2 eggs
  • Put cup to oven
  • ...wait
  • Profit?
Ok, let's try =)

Monday, September 29, 2014

Cheap breadboard wires

When testing circuits on a breadboard or my modules, I often need jumper wires with non-standard length. Yes, there are packs of factory wires in shops, but why buy, when you can make them? =)



Saturday, September 27, 2014

Atmega8/48/88/168/328 EV-X2 board

Today I've made another MCU-based device: breadboard-like unit with Atmel Mega88 MCU core.


EV-X2 board with my USBASP connected

Device contains:

  • Built-in 5V supply (L78M05) for MCU
  • 3pcs 5V outputs for external devices
  • Onboard AVRISP socket
  • Reset button
  • Clamping zeners for ADC6 and ADC7 inputs
  • Switched I2C pull-up's (not exists on photos, I don't have dual DIP switches now, it will be installed later =( )


Wednesday, September 17, 2014

Open-source electronics calculator

Features

  • Calculator for MC34063 (all converter types)
  • Resistor voltage divider (simple with match finder and 3-element with pot trimmer)
  • Basic calculator (current, power, etc.)
  • LM2576 buck converter + Vout calculator
  • TL431 reference calculator + part match finder
  • Zener diode references and calculator
  • LED series resistor calc
  • Atmel MCU timer calculator
  • Voltage drop in a wire/cable
  • Parallel/series element connection
  • Resistor color band decoder
  • Reactive resistance (L/C) calculator


Build links and source code (Delphi 7) available on Google Code.
Browse build archives on Google Drive

Tuesday, September 2, 2014

DC-DC Boost LED driver (based on MC34063)

New update of my DC-DC boost LED driver (full story you can see here (in Russian)). Added output overvoltage protection (D2,D3) and D1 changed to Vishay 30BQ100. Also I've added simple amplifier for current-sense resistor, so it can be now 1W (1 Ohm for 700mA LEDs, 2 Ohm for 350 mA).

Inductor: 60 turns of 18AWG copper wire on T90-52 core (I've used inductor from dead ATX PSU).

Please note: There is no short-circuit protection for output!


Some other notes.

  • Overvoltage limiting 1W zener diodes D2 and D3 may be changed to single 0.5W zener for appropriate maximum output voltage. For example BZX55C47 for max. 47V output.
  • Maximum output power depends on primary power supply maximum load capability, current sense resistor R1, MOSFET Q1, inductor coil and flyback rectifier D1.
  • This circuit cupports max. 16V input (limit by MOSFET driver).
  • NCP3065/66 is more suitable for CC LED driving (lower feedback voltage) but I don't have them now for test.


Thursday, July 31, 2014

Simple precision rectifier

Some time ago I've assembled a simple circuit of full-wave precision rectifier to feed signal from 50Hz AC current transformer to Atmega ADC input.
Here this unit schematic:
(picture taken from from sound.westhost.com)

Everything was fine, except strong self-oscillation of first opamp on one of half-waves (after some time TL072 become hot!). Bypass D1 with a tiny 0805 SMD capacitor 560pF completely removed this "bug" =)

And at last I've changed opamp to LM358. No significant changes and distortions on output. D1,D2: 1N4148.
Opamp is powered +/- 15V.

Tuesday, January 21, 2014

Yep, I'm here =)

In this blog you'll find some interesting electronics and MCU stuff.

BTW: English is not my native language, so excuse me for mistakes =)