Alarm schematics

Build a robust and reliable smoke detection system with this innovative circuit, safeguarding your home and pets. This design utilizes a 240VAC mains-powered smoke detector, isolated with a 12V system for safe low-voltage wiring. Experience the power of a bridge rectifier, optocoupler, and SCR to activate a high-intensity piezo siren or control larger loads like emergency lights – a must-have for peace of mind.... [read more]

Build a powerful, high-efficiency oscillator circuit using a complementary transistor pair to drive your loudspeaker. This innovative design, featuring 200mA output, allows you to create a sustained, steady tone by charging a capacitor, unlocking a world of sonic possibilities.... [read more]

Create a portable personal alarm system with a powerful 3V oscillator and loudspeaker, perfect for deterring theft and ensuring your safety. This compact circuit, housed in a protective case, utilizes a sensitive reed switch and magnet to trigger a loud alarm when your bag is unexpectedly snatched. ... [read more]

Build a powerful, covert alarm system for your laptop using this innovative circuit. This miniature alarm generator, powered by a 12V battery, protects your valuable tech with a sensitive tilt-activated alarm. Assemble this compact, matchbox-sized system using readily available components and a custom-built tilt switch for ultimate security.... [read more]

Build your own smart outdoor lighting system and transform your home with an innovative acoustic signal – a brilliant blend of security and convenience. This circuit generates an alert each time your lamp is activated, offering a unique solution for enhanced safety and a touch of technological brilliance. Discover the secrets to creating this powerful system and unlock a new level of control over your outdoor environment.... [read more]

Build your own secure alarm system with this detailed schematic! This 12-keypad design unlocks nearly 100,000 unique five-digit codes, offering unparalleled protection. Follow the step-by-step guide and veroboard layout to energize or de-energize a 12-volt relay, activating a green LED with your custom security code.... [read more]

Build your own sophisticated security system with this 12-key keypad! Unlock over 10,000 unique codes and create a powerful alarm system. Design your ideal security solution with this versatile schematic, featuring a 12-key matrix, perfect for a robust circuit board layout. Master the art of coding with this intuitive design and safeguard your space with confidence.... [read more]

Build your security system with this innovative single-zone alarm, designed to safeguard your space and empower you with precise control. Customize exit, entry, and siren cut-off timers for ultimate protection, and utilize a 5-15V power supply, including battery options, to ensure reliable operation. Achieve up to 20 minutes of siren activation, expertly tailored to your needs.... [read more]

Build a robust and reliable security system for your garage or shed with this enhanced alarm circuit. Featuring 30-second entry and exit delays, a timed siren cut-off, and automatic reset functionality, this system provides peace of mind and flexible operation. Powered by 5 to 15 volts, including a 9-volt battery, it’s ideal for battery-powered or mains operation, empowering you to safeguard your space effectively.... [read more]

Build a powerful fire door alarm circuit and safeguard your space with this innovative design. This easy-to-construct circuit, powered by a 9-volt battery, provides a crucial 30-second warning if a fire door remains open, ensuring rapid response and proactive safety. Customize the beep duration and frequency for precise monitoring and control your security system with adjustable resistor values.... [read more]

Build a powerful, responsive security system with this easy-to-construct alarm circuit. This innovative design, powered by a readily available 9-volt battery, offers exceptional reliability and a customizable output time – from a short beep to a prolonged alert lasting up to 30 minutes or more. Unlock your creativity and transform this simple circuit into a sophisticated intruder alarm, perfect for safeguarding shops, reception areas, and beyond.... [read more]

Build powerful and reliable self-contained alarm circuits with these innovative designs. Featuring three distinct alarm schematics – A, B, and C – each utilizes a Complementary Latch for minimal standby current, less than 2uA, dramatically extending battery life. Optimize performance and enhance siren output with adjustable R1 values.... [read more]

Build innovative alarm circuits with this collection of 8 schematics, perfect for battery-powered projects. Customize timing intervals and outputs using switches, thermistors, and a piezo buzzer, unlocking endless possibilities for your next electronics design.... [read more]

Build a robust security system with this innovative alarm, featuring a 30-minute siren cut-off delay – perfect for safeguarding your property and providing peace of mind. ... [read more]

Build a sophisticated and reliable burglar alarm system with this intuitive single-zone circuit. Featuring automatic Exit and Entry delays, plus a 15-minute Bell Cut-Off, this design empowers you to safeguard your property with precision. Easily integrates with normally-closed sensors like magnetic reed contacts and micro switches, and with a simple modification, accommodates normally-open triggers for comprehensive protection. Fine-tune delay times – Exit, Entry, and Bell Cut-Off – to perfectly match your needs, unlocking a powerful tool for proactive security.... [read more]

Build a robust security system with this intelligent circuit, featuring adjustable Exit and Entry delays, and a reliable Siren cut-off. Customize timing with components R4, R12, R13 and create a powerful deterrent against intrusion – perfect for integrating with Pressure Mats, Magnetic Reed Contacts, and more.... [read more]

Build your ultimate security system with this simple transistor-based burglar alarm. Featuring automatic Exit and Entry delays, a timed Bell Cut-off, and a system Reset, this 30-second alarm empowers you to protect your property. Expand your defense with a modular design, adding as many as you like – perfect for buildings requiring up to four zones.... [read more]

Build your own powerful and adaptable burglar alarm system with this intuitive SCR-based circuit. Expand from a single zone to multiple zones, safeguarding your property with customizable Exit/Entry delays and a timed Bell Cut-off. Perfect for protecting buildings of any size, this system empowers you to create a secure environment and provides precise control over your security.... [read more]

Build a robust security system with this versatile alarm, designed to protect your space with a single, powerful siren. Customize your protection with expandable zones and tailor delays to your specific needs. Create a sophisticated and secure environment, safeguarding your property and peace of mind.... [read more]

Build a robust security system with this versatile alarm circuit, designed for complete protection. Expand your system with expansion modules to create multiple zones, pinpointing intrusion attempts and providing up to 40 minutes of continuous alarm signaling. Secure your property with customizable entry and exit delays, and 24-hour personal attack/tamper protection – empowering you to safeguard your most valuable assets.... [read more]

Build a sophisticated two-zone alarm system with precise timing controls, utilizing capacitors and resistors to customize delays up to ten minutes. Master exit and entry sequences, incorporating a one-time siren activation module for ultimate security.... [read more]

Build a powerful anti-theft device and secure your valuables with this compact circuit. This innovative design, utilizing a 3V battery and a high-efficiency oscillator, emits a startling alarm when a bag is snatched, offering immediate protection and peace of mind. Perfect for safeguarding bags, doors, and windows.... [read more]

Door alarm circuit: Build your own security system with this innovative design, featuring a flashing LED and audible beep to alert you of unauthorized access. This easy-to-assemble circuit provides peace of mind by signaling when a door handle is touched from the outside.... [read more]

Unleash your ingenuity and build a resilient, self-latching circuit! This innovative design harnesses mains power and battery trickle-charge to provide automatic illumination or a powerful alarm – perfect for safeguarding your projects. With four switchable options and a robust design featuring a 220Vac mains connection, this circuit is a testament to clever engineering. Build it today and experience the thrill of a self-sustaining system, ready to activate automatically during power outages.... [read more]