Wednesday, February 25, 2009

Hobby Projects


3V Battery powered
Beeps after a fixed minutes delay
Beeps when hears your whistle
A gadget suitable for key-holders, games etc.
Dual-purpose test-instrument
Very simple circuitry, 1.5V Battery-operated
Short-range 35KHz operation, single-channel units
Simple circuitry, no outer antennas required
Easily adjustable, high sensitivity circuit
Minimum parts counting
Automatic switch-on when it gets dark
6V or 3V battery operation
Four timing controls - 12V supply
Suitable for Halloween or Christmas props
17 LEDs in four groups bar-mode sequence
Suitable for shop-windows animation etc.
LED goes to steady state after a preset number of flashes
Two simple, wide supply range operating circuits
Special design for shop-windows animation
Useful for many types of touch controls
Three circuit options
Can be synchronized to Christmas tree flashing lights
LED sequencer: follows the rhythm of music or speech
9V Battery-operated portable unit
Two strips of LEDs fading in a complementary manner
9V Battery-operated portable unit
Very simple, versatile modular design
No limits to the number of modules used in the ring
Agreeable, very close sound imitation
Suitable for sound effects, door-bells etc.
Switch-mode driven 1.5V bulbs
Portable unit - 3V battery supply
Especially designed for Christmas tree lamps
Replaces old thermally-activated switches
Simple photo-sensitive circuit
3V battery supply
230 or 115 Vac mains operated
Very simple circuitry
Tests transistors and diodes for polarity
Simple circuitry - 9V Battery operation
Simple circuitry - No ICs
12V Battery operation
Mimics the now discontinued LM3909 IC
Can be adapted to a wide variety of applications
Two LED-eyes follow the rhythm of music or speech
3V Battery-operated device suitable for pins or badges
Suitable for battery-operated devices
Fixed 35 minutes delay
Indicates the basic integrity of a printed board
Self-powered - 3 to 30V range
Acoustic check of transistor and diode junctions
Also suitable as continuity tester
Signals when an on-circuit battery is exhausted
5V to 12V operating voltage
Max. range: 9.950 meters with two digits
Slip it in pants' pocket for walking and jogging
Double tone Police sound
Single tone old ambulance sound
Small, portable, anti-bag-snatching unit
Also suitable for doors and windows control
Voltage range: 0.7 - 24V
Current limiting range: 50mA - 2A
Minimum parts counting - Improved version
3V battery operation
Ideal to operate 3 to 24V DC existing on-circuit lamps
LED operation is also possible
Astonishing effect
4.5V supply
Flashing 13 LED unit, 3V supply
Also suitable for jogger/walkers
Funny gadget for props and jokes
5 - 12V Battery operation
Accurate, finger-operated portable unit
3 - 12V Battery supply
LED or bulb switch off with a puff
Funny gadget - 3V Battery supply
Simple add-on for a single-rail supply
±2.5V to ±15V output
Three channels - Three operating modes
Completely ac-insulated circuit board

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