 Running Message Display
Light emitting diodes are advantageous due to their smaller size, low current consumption and catchy colors they emit. Here is a running message display circuit wherein the letters formed by LED arrangement light up progressively.
Programmable Digital Code Lock
A programmable code lock can be used for numerous applications in which access to an article/gadget is to be restricted to a limited number of persons. Here is yet another circuit of a code lock employing mainly the CMOS ICs and thumbwheel switches (TWS) besides a few other components.
Factory Siren
This circuit produces a sound similar to a factory siren.
It makes use of a 555 timer Ic used as an astable multivibrator of a center frequency of about 300Hz.
JAM-Just A Minute
This jam circuit can be used in quiz contests wherein any par- ticipant who presses his button (switch) before the other contestants, gets the first chance to answer a question. The circuit given here permits up to eight contestants with each one allotted a distinct number (1 to 8).
Electronic Scoring Game
You can play this game alone or with your friends. The circuit comprises a timer IC, two decade counters and a display driver along with a 7-segment display. The game is simple. As stated above, it is a scoring game and the competitor who scores 100 points rapidly (in short steps) is the winner.
Ultrasonic pest repellent
It is well know that pests like rats, mice etc are repelled by ultrasonic frequency in the range of 30 kHz to 50 kHz. Human beings can�t hear these high-frequency sounds.
Sleeping-Aid
Many people experienced sleeping well in natural surroundings, into a tent or a wooden hut. This fact is due not only to the healthy atmosphere but also from our unconscious ability to perceive natural Earths magnetic-fields.
Muscular Bio-Stimulator
This is a small, portable set, designed for those aiming at look improvement. The Bio-Stimulator provides muscles' stimulation and invigoration but, mainly, it's an aid in removing cellulitis.
Voltage follower with 1G ohm input resistance
This circuit uses an LM11 to form a voltage follower with 1G ohm input resistance built using standard resistor values.
7 Segment LED Counter
This simple counter can be used to count pulses
Nocturnal Animals Whisker
This circuit proved very useful in keeping away from a terrace or a porch some bats and other nocturnal animals. You can use it for similar or different purposes.
Whistle Responder
This device beeps intermittently for approx. two seconds when a person in a range of about 10 meters emits a whistle.
Keys Finder
Imagine that is morning , you barely anticipate the bus for work and you can't find your keys. If you suffer from this situation frequently, this circuit is ideal for you. A fizzle is the only thing you have to do. The overall circuit is small enough to attach it to your keys.
IR Remote Control Jammer
Don't like your little brother's TV channel selection? Hate the volume your wife sets the stereo at? Want to just annoy someone? This circuit does all that and more by jamming most IR remote signals. The circuit releases a flood of pulsing IR light that confuses the reciever by corrupting the data stream.
Ultrasonic Dog Whistle
One more circuit with famous NE555 timer circuit. This one produces ultrasound which can be heard by many animals. It's built to be "loud".
Magnetic Gun
This little gun can propel a small slug about 1.5 meters high, or 2.5 meters horizontally. It produces magnetic field using four coils and 4017b and NE555 which drive coils.
Magic Wand Conjuring Trick
This is circuit diagram of an interesting toy. It lights up if You move "magic wand" over it in the precisely right way that only you know!
Insect Repellant
22kHz oscillator which produces sound that should repel insect. It has adjustable frequency. Its built around one CMOS 4047 circuit.
Muscular Bio-Stimulator
This is a small, portable set, designed for those aiming at look improvement. The Bio-Stimulator provides muscles' stimulation and invigoration but, mainly, it's an aid in removing cellulites.
High Quality Intercom
A very high quality intercom, which may also be used for room monitoring
Sound Effects Generator
This circuit uses a UM3561 IC to produce four different sound effects
High Voltage Stun Gun
High Voltage Stun Gun. It's not a toy!
TV remote control Blocker
Just point this small device at the TV and the remote gets jammed.
Doorbell for the Deaf
This circuit provides a delayed visual indication when a door bell switch is pressed. Very helpful for deaf people.
Whistle Responder
Beeps when hears your whistle.
A gadget suitable for key-holders, games etc.
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