Projects of the ‘Electronics’ Category

Building power overcurrent protection with restoring on timer

2011 (2 weeks), private project, 1 developer
result: 1 sample is implemented
tools: Oscilloscope & solder iron

It is developed for protection of country side building that is 7-15 kW load of non-stable 220V power network. It disconnects load (building with power stabilizer) if its current exceeds the customizable level (25-70 amperes) and then it runs timer. Timer delay may be set in the range of 2 to 24 minutes. Device restores power to load when timer’s delay is passed.
It is designed to work at wide range of power: 90 to 330 volts (tested). In normal condition (220V) this device consumes only 2,5 Watts and 6 Watts when load is disconnected.
Such device becomes useful when power stabilizer does not have automatic restoring of power after overcurrent condition. This leads to total discharging of backup batteries of UPS which follows stabilizer even if power is already restored.
At the country side overcurrent condition often occurs when power network voltage drops. For example, if voltage drops to about 147 volts then input current of stabilizer rises in 1.5 times (while building consumes the same power after stabilizer).

Electronics, Power Units, Sensors/Detectors

10 kV power unit working with regular shunting

2008, customer Bolotov B.V., outsourcing, 1 developer
result: 2 versions were implemented
tools: Oscilloscope & solder iron

1) 220 to 14kV multiplier (C-D);
2) switching one with 10kV output.
It is used to generate very hi-current pulsing as often as possible (<1 sec period).

Electronics, Power Units

Christmas Tree RGB LED cell wireless control

2008, private project, 1 developer
result: designed 1 sample
dev. OS: Windows XP; MC: ATtiny13; languages: C; tools: PN, AVR C cross-compiler

Battery powered RGB LED for Christmas-tree that lights with random color/speed is wireless controlled (on/off) by external device (wire loop around the tree). RGB LED has MC color control.

Electronics, Home/Entertainment, Microcontrollers

MC controlled Ultrasonic cell

2008, private project, 1 developer
result: 50%: analog part was designed
dev. OS: Windows XP; MC: ATtiny13; languages: C; tools: PN, AVR C cross-compiler

Combined MC controlled source/receiver ultrasonic cell for distance/presence detector.

Electronics, Microcontrollers, Sensors/Detectors

Noise Reduction of MC based Low Frequency Sound Generator

2007, customer Bolotov M.B., outsourcing, 1 developer
result: problems with output noise were solved
MC: i51; languages: Assembler i51; tools: Oscilloscope & solder iron

MC based 0,01-30 Hz sine wave sound generator with power amplifiers avails programmed changing of output frequency. FW was verified.
Power modes and construction were changed.

Electronics, Microcontrollers, Testing/Improving

2-8 channels phone line PC adapter

2004, customer: private project, 1 developer
result: 8 and 2 channels versions were implemented
OS: Windows XP; tools: Orcad, oscilloscope & solder iron

2 channels per board adapters of phone line. Decoupled output to Sound Blaster input of PC, line on-hook sensing of each line via Joystick port. Amplifiers with auto gain control.
It was made to be used with ready software for calls registration Atropos-SB (

Design, Electronics, PCB Design, Phone/Sound

USB Camera noise reduction and PCB design correction

2003 (2 months), customer: “Sumix Corporation”, full-time, 1 developer/tester
result: Noise and temperature dependency reduced dramatically, about 30 boards were corrected
OS: Windows 98; languages: VB 6.0; tools: oscilloscope & solder iron

Sumix developed SMX-110 USB camera was inspected and tested for picture noise. Picture noise testing application was written using ready API.
Power modes, PCB design and camera construction were corrected to achieve as minimal noise as supplied CMOS sensor avails.

@ Software, Electronics, Testing/Improving

PC board for Video input, digital software decoder of PAL color component

1991-1992, joint project: with Production Cooperative “Informtechnika”, 1 developer
result: sold 5 boards
OS/Hardware: DOS/PC/designed ISA boar; languages: C; tools: TC 2.0, oscilloscope

Developed board grabs composite video signal with 12MHz/8bits sampling. Data was written directly to PC RAM using Master mode of ISA bus. Board had about 40 logic DIPs and fast ADC.
Grabbed composite PAL signal data is decoded by software decoder to get color picture.

Read more…

@ Software, Algorithms and Data Processing, Data Acquisition and Control, Electronics, PCB Design, Signal Processing, TV/IPTV/Video

Digital clock with alarm

1983-1984, home and electronics section
result: hope it still works at my teacher’s home
tools: oscilloscope & solder iron

It was my first developed schematic. About 35 logic CMOS DIPs. Clock had 4 digits each of 27 red LEDs – ready military indicators with 4-bits logic input. It has external PS, backup battery and 5 minutes grid of alarm time.

Electronics, Home/Entertainment

Christmas-tree running lights

1979, electronics section
result: it was working during several years
tools: solder iron

It was my first soldered device using ready schematic: 3 thyristor controlled 220V lamp garlands. Garlands of 20 lamps each were soldered by my father.
Later the control device was re-factored for random blinking.

Electronics, Home/Entertainment