• Register
  • Login
  • Search 4 million + Products

    83 x Alarms Circuits

    Browse through a total of 83 alarm projects, circuits and kits.

    PIR sensors   fire alarms   infrared alarms   motion sensors   sirens   smoke alarms   temperature sensors   touch alarms  

    Night Security Light with Hacked PIR sensor Security lighting is widely used as a preventive measure against intrusions on a physical piece of property. Since adequate lighting around a physical structure reduces the risk of an intrusion, security lighting can be used in residential settings to increase the feeling of safety. Presented here is a trusty security light activated by a passive infrared sensor, turning on...
    Little Laser Trip Wire Circuit Little Laser Trip Wire circuit presented here can detect movement of people or objects while passing through the laser beam and trigger security alarms as alert signals to those concerned. What is behind this little laser trip wire is actually a red laser line that triggers a latch-switch when tripped. Here it is created by a single laser beam,...
    Optical Rain Sensor RG-11 Review Dreaming about a little device capable of measuring rainfall or closing a skylight when it starts raining? Recently I found an amazing Optical Rain Gauge introduced by Hydreon Corporation. The RG11 Optical Rain Gauge is a novel, futuristic and relatively inexpensive optical rain sensor good for hobbyists and experimentalists, including those who need a sensor to trigger some electromechanical...
    Arduino RFID Reader RC522 + Access Control System I just received my RC522 RFID reader and made this simple Arduino access control system that uses the reader, a buzzer for the alarm and a relay shield for the security system. The relay can be used to open a door lock and if you need a louder alarm then you can replace the small buzzer with a high...
    Musical Doorbell as a Shadow Sensor Alarm Our market is flooded with cheap and cheerful AC/DC Multi-Tune Musical doorbells. Most of these doorbells are built around customized microcontrollers from China, and usually run on two penlight (1.5V AA type) cells. We can safely trigger these doorbells using the existing AC 230V mains supply wiring of the doorbell switch. Did you know? With a slight alteration, you...
    3-Wire Cooling Fan Monitor Cooling fan is an essential part in almost all power electronics systems. Here is a simple circuit for monitoring the instrument cooling fan activity to raise an audio-visual alert incase of the fan failure. This is a proven solution to prevent costly disasters caused by over temperature inside the power electronics instrument. This little adapter circuit can be used...
    GSM Home Security Alarm System with Arduino This project deals with the design & development of a theft control system for home, which is being used to prevent/control any theft attempt. The developed system makes use of an embedded system (comprises an open hardware microcontroller and a gsm modem) based on Global System for Mobile communication (GSM) technology. The designed & developed system can be installed...
    Door Opening Alarm with Sound Alert The door opening alarm circuit or “Front Office Visitor Alert” is used for alerting you when a customer is at your office/shop. It will produce a beep sound when each new customer or visitor is entering, and will automatically switch OFF after few seconds. Schematic of the Door Opening Alert Circuit 555 datasheet In this circuit timer IC NE555...
    Two-Door Buzzer with Display The Two-door Buzzer with Display is applicable and well suited to be used in a house having two gates or doors that are distant from each other. It helps the person inside the house by providing an alarm and a number display determining which door where the visitor is. It also saves time and effort as the owner does...
    Vibration Sensor Alarm The idea behind this compact and economical Vibration Sensor Alarm is very simple. It uses a cheap and cheerful vibration sensor to drive a piezo-sounder. As can be seen in the circuit diagram, it is wired around one tiny microcontroller PIC12F675. Batteries are suitable for the power supply, because the circuit only takes less than 5mA in idle state....