This shadow detector circuit operates using two LDRs and effectively detects the difference between the light levels and triggers a loud audible warning siren. In circuits which uses a single LDR (photoresist), the detection may not be as sharp as with two LDRs discussed here.Operational details of the shadow detector circuit may be studied as […]
Alarm
Simple Ultrasonic Sound Sensor Alarm Circuit using Opamp
This article discusses a simple ultrasonic sound sensor alarm circuit which may be appropriately set for detecting sound pressures well above the normal human listening capacity, that may range from 20 kHz and over. Ultrasonic Concept Ultrasound or ultrasonic sound waves was probably invented even before humans existed on this planet by a few of […]
5 Simple Alarm Circuits for Protecting your Home/Office from Theft
The following article discusses a few very simple intrusion detector circuits, or ant-theft alarms. The presented designs are easy to build yet extremely effective with the functions. How the Circuits Works An intruder alarm basically consists of a sensor and a trigger stages, which work together to produce the required detection. The sensor detects the presence […]
3 Smart Laser Alarm Protection Circuits
In this post I have explained the making of 3 simple yet effective smart laser alarm protection circuit using the IC 555, for securing a specified restricted zone from human interventions. The idea was requested by Mr. Collins. Circuit Objectives and Requirements 1) The Design Parts List IC 555Pinouts Circuit Operation The proposed smart yet […]
Simple Water Heater Alarm Circuit
In this post I have explained a simple water heater alarm circuit which may be used as a safety device for getting indications regarding the switched position of a water heater or a geyser through intermittent buzzer actuation. The idea was requested by Mr. Mathew. Technical Specifications To be frank i am new to your […]
Power Interruption Alarm Circuit for Instant Power Failure Indications
This power interruption alarm circuit will alert you whenever there’s a power failure or an interruption in the mains. In some special conditions it becomes imperative to know whether the mains that powers some important system or circuit is absent. By: Manisha Patel How the power failure alarm works This proposed circuit is connected to […]