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13 Color LED Rainbow - ….(design added 03/08) |
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4 Digit Keypad - (circuit design added 8/03) |
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5 Zone Alarm Circuit - (design circuit added 8/02) |
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A CMOS 4060 Burglar Alarm - This is a single zone alarm, with automatic exit,
entry and siren cut-off timers. It will accommodate all the usual types of
normally-closed input devices, such as magnetic reed contacts, foil tape, PIRs etc.
But it's easy to add a normally-open trigger....(circuit design added 06/07/08) |
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A CMOS Based Motorcycle Alarm - This circuit features an intermittent siren
output and automatic reset. It can be operated manually using a key-switch or a hidden
switch; but it can also be wired to set itself automatically when you turn-off the
ignition....(circuit design added 06/07/08) |
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A CMOS Based Single Zone Alarm - This circuit features automatic Exit/Entry
delays, timed Bell Cut-off and System Reset. It has provision for normally-open and
normally-closed switches and will accommodate the usual input devices (Pressure Mats,
Magnetic Reed contacts, Foil Tape, PIRs and Inertia Sensors)....(circuit design added
006/07/08) |
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A CMOS Based Vehicle Anti-Theft Alarm - This car alarm circuit features Exit and
Entry delays, an instant alarm zone, an intermittent siren output and automatic Reset.
By adding external relays you can immobilize the vehicle and flash the
lights….(circuit design added 06/07/08) |
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A CMOS Single Zone Intruder Alarm - This circuit features automatic Exit and Entry
delays, timed bell cut-off, and system reset. It has provision for normally-open and
normally-closed switches, and will suit all of the usual input devices (Pressure Mats,
Magnetic Reed contacts, Foil Tape, PIRs and Inertia-Sensors, see....(schematic added
95/09) |
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A One-Time-Only Burglar Alarm - When this alarm is activated its Siren will sound
once, for up to 20-minutes. Then it will switch off and remain off. The basic circuit
has a single zone with independently adjustable Exit and Entry delays. This will be
adequate in many situations. However, there's also range of Expansion Modules. These
will allow you to add any number of Instant Zones, Tamper Zones and Personal Attack
Zones to your system. (circuit design added 04/05/06) |
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A Shed/ Garage Alarm - This is a basic single-zone burglar alarm circuit. Its
features include automatic Exit and Entry delays. It has an extremely small standby
current. This makes it ideal for battery-powered operation. Use it in your caravan,
mobile home, lock-up, or anywhere mains power is not available. (circuit design
added 04/05/06) |
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A Simple Fire-Door Alarm - This circuit will let you know when something that
should be kept closed, has in fact been left open. Attach it to a Fire-Door. It will
allow you to pass through the door as usual. However, if it's left open for more than
30-seconds or so, the buzzer will sound. Photo (circuit design added 04/05/06) |
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A Simple Shop-Door Alarm - Attach this circuit to the door of an unattended shop,
or reception area, and the sound of the buzzer will tell you when you have a customer.
Add a siren, and it becomes a simple intruder alarm. Photo (circuit design added
04/05/06) |
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A Simple Transistor Based Motorcycle Alarm - This is an even simpler transistor
based motorcycle alarm. The circuit features a timed output and automatic reset. It
can be operated manually using a key-switch or a hidden switch. By adding an external
relay, it will set itself automatically, and/or immobilize the machine, every time you
turn-off the ignition. It's easily adapted for a 6-volt system, so it will protect
your "Classic Bike"(circuit design added 04/05/06) |
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A Simpler CMOS Single Zone Alarm - This circuit features automatic Exit/Entry
delays, timed Bell Cut-off and System Reset. It will accommodate the usual
normally-closed input devices (Magnetic Reed contacts, Micro Switches, Foil Tape and
PIRs). And, with a simple modification, a normally-open trigger may be added .
(circuit design added 04/05/06) |
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A Transistor Based Single Zone Alarm - The circuit features automatic Exit and
Entry delays, timed Bell Cut-off and System Reset. It has provision for normally-open
and normally-closed switches and will suit the usual input devices (Pressure Mats,
Magnetic Reed contacts, Foil Tape, PIRs and Inertia Sensors). (circuit design
added 04/05/06) |
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Alarm control keypad - (circuit design added 8/03) |
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An Enhanced Shed/ Garage Alarm - This is an enhanced version of the simple
Garage/Shed Alarm. The Entry and Exit delays have been increased to about 30-seconds,
and I've added a timed Siren cut-off and automatic Reset. I've also replaced the LED
with an entry Buzzer. These enhancements mean that the new version will have a much
wider application. Photo (circuit design added 04/05/06) |
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An Expandable Multi-Zone Modular Burglar Alarm - This circuit features automatic
Exit and Entry delays and a timed Bell Cut-off. It has provision for both
normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone.
By using the Expansion Modules, you can add as many zones as you require; some or all
of which may be the inertia (shock) sensor type. (circuit design added 04/05/06) |
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An Expandable SCR Based Burglar Alarm - This is a simple SCR based burglar alarm
circuit. Its features include automatic Exit and Entry delays, together with a timed
Bell Cut-off and Reset. The basic alarm has a single zone. This will be adequate in
many situations. However, the modular design means that you can add as many zones as
you like to the system. Details of a Four-Zone expansion module are provided.
(circuit design added 04/05/06) |
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An Expandable Transistor Based Burglar Alarm - This transistor based alarm
features automatic Exit and Entry delays, together with a timed Bell Cut-off and
system Reset. Along with the Exit/Entry zone, the basic alarm board has one Instant
Zone. This will be adequate in many situations. However, the modular design means that
it's easy to add as many zones as you like to the system. Details of a Four-Zone
expansion module are provided. (circuit design added 04/05/06) |
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An SCR Based Burglar Alarm - (electronic design added 6/07) |
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Analog Video Router - Intersil Application Block Diagram (app note added
6/06) |
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Anti Theft Motorcycle Alarm - (electronic design added 9/02) |
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Anti-Bag-Snatching Alarm - (electronic Circuit / Schematic added 10/04) |
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Anti-Theft Alarm for Bikes - (electronic Circuit / Schematic added 10/04) |
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Anti-Theft Security for Car Audios - (electronic Circuit / Schematic added 10/04) |
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Auto Burglar Alarm (Randy Linscott) - This alarm circuit is based on two 555
timers. The alarm will sound your car horn if anyone opens the car door while the
circuit is armed. The timers will allow you to leave the car without sounding the
horn. To turn the circuit on S1 must be closed.….(added 08/08/08) |
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Automatic Door Opener with PIC12c508 - This circuit can be used to operate an
electric strike or an electromagnetic lock on a door. It is not door being
opened/closed, but a small electromagnetic strike which unlocks door…. (added
4/05) |
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Automatic Intruder Alarm - (electronic design added 6/07) |
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Automatic Room Lights - An ordinary automatic room power control circuit has only
one light sensor. So when a person enters room it gets one pulse and
lights come ‘on.’ When person goes out it gets anor pulse and lights go
‘off.’ But what happens when two persons enter room, one after or? It gets
two pulses and lights remain in ‘off’ .... (added 10/05) |
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Battery-Powered One-Time-Only Burglar Alarm - This is a single zone alarm, with
independently adjustable Exit, Entry and Siren Cut-Off timers. When the alarm is
activated its Siren will sound once, for up to 20-minutes. Then it will switch off and
remain off. If you wish, you can use a mains power supply. But the extremely low
standby current makes battery power a realistic option. (circuit design added
08/08/08) |
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Build yourself a Witness Camera - The Witness Camera is an automated,
self-recording surveillance camera, that uses a gigabyte-class flash card as recording
media. I designed the Witnesscam because available surveillance solutions were too
expensive or impractical for home use. I built the system from a VGA CMOS colour
camera, a passive-infrared (PIR) movement sensor, an ATmega32 processor, and a 1GB
SD-card....(design added 06/05) |
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CMOS 4060 Burglar Alarm - This is a single zone alarm, with automatic exit, entry
and siren cut-off timers. It will accommodate all the usual types of normally-closed
input devices, such as magnetic reed contacts, foil tape, PIRs etc. But it's easy to
add a normally-open trigger....(circuit design added 06/07/08) |
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CMOS Based Motorcycle Alarm - This circuit features automatic Exit/Entry delays,
timed Bell Cut-off and System Reset. It has provision for normally-open and
normally-closed switches and will accommodate the usual input devices (Pressure Mats,
Magnetic Reed contacts, Foil Tape, PIRs and Inertia Sensors)....(circuit design added
006/07/08) |
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CMOS Based Vehicle Anti-Theft Alarm - This car alarm circuit features Exit and
Entry delays, an instant alarm zone, an intermittent siren output and automatic Reset.
By adding external relays you can immobilize the vehicle and flash the
lights….(circuit design added 06/07/08) |
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Combination Digital Lock - A multiple input combination loack using CMOS counter
IC's. Flexibility and code change is allowed by changing output connections.
(electronic design added 9/02) |
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Combination Lock PIC16F84 - (circuit design added 8/03) |
| Combination Lock-Digital - (electronic design added
6/07) |
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Cut Phone Line Detector (Aaron Cake) - Can be used to alarm security system (added
2/03) |
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Cut Phone Line Detector (Tony van Roon) - (schematic / circuit added 10/02) |
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DayLight Alarm - The circuit presented here wakes you up with a loud alarm at the
break of the daylight. Once again the 555 timer is used here. It is working as an
astable multivibrator at a frequency of about 1kHz. The circuit's operation can
be explained as follows: When no light falls on the LDR, the transistor is pulled high
by the variable resistor. Hence the transistor is ..... (added 10/05) |
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Digital Combination Lock - (electronic design added 9/02) |
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Digital Electronic Lock (Bill Bowden) - The digital lock shown below uses 4 common
logic ICs to allow controlling a relay by entering a 4 digit number on a keypad. The
first 4 outputs from the CD4017 decade counter (pins 3,2,4,7) are gated...(electronic
schematic / circuit added 11/05) |
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Door/Window Sensor Resists Tampering - 01/21/99 EDN-Design Ideas: The simple,
inexpensive circuit in Figure 1 detects a failure (or deliberate tampering)on lines
connected to normally closed switch sensors. For example, common door interlocks and
door/window sensors consist of normally open or normally closed magnetic reed
switches. Depending on the monitoring configuration, an open or short on a line may go
undetected, thus preventing alarm activation. Embedding a resistor in a normally
closed sensor and using bipolar dc power supplies produces the balanced configuration
in Figure 1. A short or open on a line (or sensor activation)produces a net positive
or negative voltage at the input of the Q1-Q2 pair.....(design idea added 11/05) |
