Time control is very important in out daily life. Sometimes we do forget small tasks. So this 5 To 20 Minutes Alarm Timer Circuit helps us remember. It gives alarm after a fixed time as the circuit uses popular IC 555 timer. Time can be selected from 5 to 20 minutes by just pressing start […]
Alarm Circuits
Simple Infrared Fire Alarm Circuit
This is Simple Infrared Fire Alarm Circuit for beginners. It use infrared receiver sensor to detect fire heat or flame light. When fire come close sensor output changes. Then LED glow and buzzer makes sound. This circuit is cheap and easy to make. It also use only few parts like BC547 transistor, LED, buzzer, IR […]
Laser Light Alarm Circuit using Arduino
This article is for simple Laser Light Alarm Circuit using Arduino. A laser light shines on an LDR. When someone blocks the laser beam, the LDR changes its value. Arduino reads this change and turns ON the buzzer to make alarm sound. A reset button stops the alarm. The system is low cost and easy […]
Simple Thermistor Based Fire Alarm Circuit
This Simple Thermistor Based Fire Alarm Circuit is very small, simple and smart. It uses a thermistor to sense heat fast. When temperature goes high the circuit wakes up and makes loud sound. No microcontroller, no complex parts. Only few components and we get a working fire alert that anyone can build at home Circuit […]
Fire Alarm Circuit using IC LM358
This Fire Alarm Circuit using IC LM358 is simple but smart. It uses a 10k thermistor and LM358 IC. It watches heat using a thermistor and makes buzzer ring when danger comes. This circuit is cheap and is good for home, school projects and safety demos. Circuit Working: Parts List: Component Value / Type Resistors […]
MQ2 Gas Sensor Circuit with Arduino
The MQ2 Gas Sensor Circuit with Arduino is a low-cost sensor. It can catch bad gas in air very quickly. When we connect it with Arduino, we make small gas alarm system. It reads gas level, show number on LCD and buzzer make sound when gas goes high. This circuit is very simple to make […]