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? =)

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 =( )

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

3A USB device charger (LM2576) (Updated)

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.

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.

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 =)