Did you know that most of the thefts at home happen when it is empty? But not everyone is rich enough to hire a security for their house and at the same time they themselves cannot be at home 24 by7. Now what if there is a system which alerts you about an intruder through a text message?The following tutorial teaches how to make you own intruder alerting system
Various types of alarms are available in market to protect the entry of unauthorized person in restricted area but they require precise alignment. The circuit described here is very sensitive and it can detect the moving person at a distance of few meters and we do not require much alignment. Circuit will give you loud alarm enough to detect the presence of person in restricted area. It can be used as fence alarm to protect your garden from animals.You can also use it at your doors to indicate that some stranger is present on door.The circuit comprises of Operational amplifier. ?A741 is used as a sensitive voltage comparator, NE555 wired in mono-stable mode. In mono-stable mode IC is once trigged, it will hold the output for a specific interval of time as defined by the timing component before returning to its original state and we are utilizing this property in our circuit.
This project extends the functionality of intruder alarm to alert a user at a distant location. The intrusion can be detected at a faraway place by making use of RF [[wysiwyg_imageupload::]]communication. For this purpose, an RF module can be used as has been explained here. This project about intruder alarm circuit can be divided into three parts, namely, IR circuit, transceiver part and the output. The IR circuit is used as a sensor to detect an intrusion in its proximity. RF module works as the transceiver here. For more details, refer wireless RF remote. The transceiver transmits the signal generated by IR sensor. It provides this signal to the data pin of decoder IC. The output part consists of a NOT gate IC 74LS04 (to invert the low signal) and a buzzer to alert the user. Read more to find out how the circuit is constructed and how it works.