Multi-Zone Burglar Alarm Circuits 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. 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. 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. 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.
Single Zone Burglar Alarm Circuits 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). 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). 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. 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. When the alarm is activated - the siren will sound for a fixed length of time. Then it will switch off - and remain off. The alarm will not reactivate. The Circuit Description offers a good introduction to the Cmos 4060 and the SCR.
Battery-Powered Alarm Circuits A Dozen Small Cmos Alarm Circuits This is a selection of small self-contained alarm circuits. They have a very low standby current; and are suitable for battery operation. Some are triggered by normally-open and normally-closed switches. Some react to changes in light or temperature. The result is a variety of output times and patterns. Four Small Transistor Alarm Circuits This is a selection of simple self-contained transistor based alarm circuits - complete with photographs. They are designed around the Complementary Latch. All may be triggered by both normally-open and normally-closed switches. They have a very low standby current - and are ideal for battery operation. 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 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 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. 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 A 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.
Alarm Control Keypads A 4-Digit Alarm Control Keypad This Keypad is suitable for the Modular Burglar Alarm. However, it has other applications. Pressing a single key will energize the relay. Entering the Four-Digit code of your choice will de-energize it. A 5-Digit Alarm Control Keypad This Keypad is suitable for the Modular Burglar Alarm. However, it has other applications. Entering the First Four Digits of your chosen Five-Digit code - will energize the relay. Entering the Full Five-Digit code - will de-energize it.
Universal Keypad-Controlled Switches A 4-Digit Keypad Controlled Switch This is a Universal version of the Four-Digit Alarm Control Keypad. I have modified the design to free up the relay contacts. This allows the circuit to operate as a general-purpose switch. I've used a SPCO/SPDT relay - but you can use a multi-pole relay if you wish. Keypad Controlled Switch No. 2 This is a simplified version of the 4-Digit Keypad Controlled Switch. I have modified the design to reduce the complexity of the circuit - and the number of components required. As a result - the code is somewhat less secure. However, there should be lots of situations where it will still be adequate.
Keypad-Operated Door-Lock Release Electronic Door Release This circuit is designed to operate an electrical door-release mechanism - but it will have other applications. When you enter the four-digit code of your choice - the relay will energize for a preset time period. Use the relay contacts to power the release mechanism. The standby current is virtually zero - so battery power is a realistic option.
Power Supply Circuits An Alarm Power Supply With Battery Back-up This Power Supply is suitable for the Modular Burglar Alarm. However, it has other applications. It is designed to provide an output of 12-volts, with a current of up to 1-amp. In the event of mains failure, the back-up battery takes over automatically. When the mains is restored, the battery recharges. A Current Limiting Bench Power Supply This is a 1-amp variable-voltage PSU. It adjusts from about 3v to 24v: and has the added feature that you can limit the maximum output current. This is invaluable when (for example) you power-up a project for the first time or soak-test a piece of equipment. An Add-On Current Limiter For Your PSU This circuit allows you to set a limit on the maximum output current available from your PSU. It's very useful when you power-up a project for the first time - or carry out a soak-test. By setting an upper limit on the current available from your PSU - you can protect both your power supply - and any device connected to it. It offers a simple and cheap alternative to the Current Limiting Power Supply A Transformerless Power Supply This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance - so it doesn't generate very much heat. The circuit was designed to provide a cheap, compact power supply for Cmos logic circuits that require only a few milliamps. The logic circuits were then used to control mains equipment, using an optically-isolated triac.
Automobile Alarm Circuits 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. Two Cmos Based Vehicle Anti-Hijack Alarms The first circuit is designed for the situation where a hijacker forces the driver from the vehicle. If a door is opened while the ignition is switched on - the circuit will trip. After a few minutes delay - when the thief is at a safe distance - the alarm will sound and the engine will fail. The second circuit is a modification of the first - offering enhanced protection in many more situations. Vehicle Anti-Hijack Alarm No. 3 Like the first two Hijack Alarms - if a door is opened while the ignition is switched on - the circuit will trip. And after a few minutes delay - when the thief is at a safe distance - the Siren will sound. But this time the engine does not go on to fail automatically. Instead - it will continue to run until the thief turns off the ignition. Then the engine will not re-start.
Motorcycle Alarm Circuits A Transistor Based Motorcycle Alarm This 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". A 555 -Timer 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. By adding external relays you can immobilize the bike, flash the lights etc. 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. By adding external relays you can immobilize the bike, flash the lights etc. It's easily adapted for a 6-volt system - so it will protect your "Classic Bike" 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" Two Simple Relay Based Motorcycle Alarms These are two - easy to build - relay-based alarms. You can use them to protect your motorcycle - but they have many more applications. If you use relays with 6-volt coils - they'll protect your "Classic Bike". Both alarms are very small. The completed boards occupy about half a cubic-inch - 8 cc. The standby current is zero - so they won't drain your battery.
Timer Circuits Two Cmos Based 24-Hour Timers A pair of multi-range timers offering periods of up to 24 hours and beyond. Both are essentially the same. The main difference is, that when the time runs out, Version 1 energizes the relay and Version 2 de-energizes it. The first uses less power while the timer is running; and the second uses less power after the timer stops. Pick the one that best suits your application. A Regularly Repeating Interval Timer This circuit has an adjustable output timer that will re-trigger at regular intervals. The output period can be anything from a fraction of a second to half-an-hour or more - and it can be made to recur at regular intervals of anything from seconds to days and beyond. Repeating Interval Timer No.2 This is a simpler repeating timer circuit. It uses just one Cmos IC - wired as an asymmetric oscillator. The length of time the relay remains energized - and the length of time it remains de-energized - are set independently.
Miscellaneous An Introduction to the Cmos 4001 This is a beginners guide to the Cmos 4001. It starts with a detailed look at the operation of the IC; and then considers its practical use in a small Battery-Powered Door-Alarm circuit. An Introduction to the Cmos 4011 This is a beginners guide to the Cmos 4011. It starts with a detailed look at the operation of the IC; and then considers its practical use in a small Battery-Powered Fire-Door Alarm circuit. An Introduction to the Complementary Latch This is a beginners guide to the Complementary Latch. It starts with a detailed look at how the Latch operates - and then considers its practical use in a small Battery-Powered Transistor Alarm circuit. An Infra-Red Remote Control Extender This is a battery powered Infra-Red Link that will allow you to change channels on your Satellite Receiver and operate the controls on your VCR & DVD from anywhere in the house. A Decimal to BCD Decoder This circuit will take the input from a keypad with up to 16 buttons - and convert it into a ''latched'' BCD output.

Useful Free Software

Free Circuit Simulator

This is a free Electronic Circuit Simulator Programme. There are versions for both Windows and Linux. I've installed it successfully on SuSE 8.2, SuSE 9.2 and SuSE 10.1 using the clear step-by-step instructions provided. It's worth downloading for the easy-to-use Schematic Drawing Tool alone.

Free PCB Design Software

Free Software - with lots of useful tips and advice - to help you Design Your Own PCB Layouts. I don't use it myself - I prefer to use Veroboard. But it's easy to learn and it's easy to use. If you've produced a PCB layout for one of my circuits - using this or any other software - I'd appreciate a copy.

Free Stripboard Layout Software

This Free Software from VeeCAD.com will help you Design Your Own Veroboard Layouts. Simply draw the circuit diagram using a schematic editor - such as the equally free TinyCAD. Then import the netlist. VeeCAD is easy to learn and easy to use. Everything you need to know is in the "Help" file.

Free Anti-Virus Software

A freeware version of this Anti-Virus Software is available for Personal Use. Regular virus updates can be downloaded free-of-charge. It's recognised by - and its status is monitored by - your Windows "Security Center". A freeware version is also available for Linux/OpenBSD/FreeBSD/Solaris.

Free Anti-Spyware Software

A free programme to help you identify and remove from your hard-drive - software routines that spy on you and compromises your privacy. You don't know they're there - and you don't know what they're up to. This programme lets you get rid of them - and the regular free updates catch any new varieties that manage to slip by. Try it - you may be surprised by what you find.

Free Anti-Spam Software

Take control of your Inbox with this small - easy to use - programme. This page includes the programme download information - together with a comprehensive guide to SPAM - and a detailed account of how to set-up the necessary filters that will recognize and eliminate it.

Free DeskPins Software

With this free programme you can add the "Always on Top" feature to any window. It's worth downloading just for your calculator. Click on the DeskPins icon in the taskbar tray. The mouse pointer turns into a pushpin. Then simply click on whatever window you want to remain on top.

Helpful Practical Guides

Drawing the Veroboard Layouts

This page shows how I draw the Veroboard Layouts published on my Website. I use a similar approach when drawing the Schematic Diagrams. Please Feel free to use the templates provided - or indeed any of my drawings - to produce your own designs.

Building Circuits On Veroboard

This is a beginners guide to building circuits with Veroboard. Starting with the schematic diagram of a small audio amplifier - it provides a detailed step-by-step account of how to translate the schematic into an actual working device. Each step is clearly illustrated by a photograph.

A Comprehensive Guide To Using Windows

You can download free chapters from the latest edition of "The Secret Guide to Computers" by Russ Walter. One of those chapters is a comprehensive guide to using the various versions of the Windows operating system. But there's a lot more than that. So even if you know all about Windows - take a look at the other free chapters.

Welcome to Ron J's Circuit Page

Multi-Zone Burglar Alarm Circuits

Single Zone Burglar Alarm Circuits

Battery-Powered Alarm Circuits

Alarm Control Keypads

Universal Keypad-Controlled Switches

Keypad-Operated Door-Lock Release

Power Supply Circuits

Automobile Alarm Circuits

Motorcycle Alarm Circuits

Timer Circuits

Miscellaneous

Useful Free Software

Helpful Practical Guides

Please Sign

My Guestbook

Welcome to Ron J's Circuit Page

Multi-Zone Burglar Alarm Circuits

Single Zone Burglar Alarm Circuits

Battery-Powered Alarm Circuits

Alarm Control Keypads

Universal Keypad-Controlled Switches

Keypad-Operated Door-Lock Release

Power Supply Circuits

Automobile Alarm Circuits

Motorcycle Alarm Circuits

Timer Circuits

Miscellaneous

Useful Free Software

Helpful Practical Guides

Please Sign My Guestbook

Please Sign

My Guestbook