Shadow alarms are widely used for security purposes. A shadow alarm is a device that generates an alarm whenever a shadow falls on it. This project can be easily [[wysiwyg_imageupload::]]installed on the windows and doors. This circuit demonstrates the principle and operation of a simple shadow alarm using LDR. Other than the LDR, the circuit consists of LEDs for input and output purposes, buzzer and a LM324 comparator IC. Keep on reading to find out how the circuit is constructed and how it can be made to work.
Intruder alarm / Burglar alarm based Home Security System
This electronic device is designed to alert the user to an intrusion. The project consists of a sensor and a control unit which are connected to each other. The [[wysiwyg_imageupload::]]sensor detects the interruption whenever an object or person comes between its transmitter and receiver. This interruption results in a signal generation which is supplied to a speaker. This way whenever an intrusion takes place, the speaker goes on. Such devices are installed at various locations in houses or offices, especially near doors, windows.In this project, the transmitter part of the circuit is an Infrared (IR) Led which transmits continuous IR rays to be received by IR receiver. The reception of rays at IR receiver results in high voltage at the output. The output of this IR sensor remains low when no signal is received. Keep on reading to find out how the circuit is constructed and what makes it work.
Fire alarm using temp sensor (LM35), opam (LM339) & 555 timer IC
At times we forget to switch off our heating devices and eventually they get damaged. Therefore there is always a need of a device which can alert by sounding [[wysiwyg_imageupload::]]an alarm if the device temperature goes beyond a particular value. Same concept can be used in this project about fire alarm. If a building catches fire then it will raise an alarm and people could evacuate the building. This circuit uses a LM35 temperature sensor along with a LM339 comparator. Interfaced to LM339 are the following components: Resistors, Capacitors, Transistors, 555 Timer, Buzzer (output). This project about fire alarm circuit is based around LM35 which is a temperature sensor and could be used to switch an alarm when temperature goes beyond a preset value. In this circuit the output of LM35 is fed to the negative pin of comparator of LM339. The positive input is connected to a preset VR1 of value 10K.
Power failure alarm using diode and astable mode of 555 timer
Sometimes there is need of devices which should intimate us when power goes off, so that we could switch off our devices if they are battery [[wysiwyg_imageupload::]]operated or they are getting power from some other limited source [such as for computer using UPS(uninterrupted power supply)]. This project can solve our purpose and can intimate us if power supply fails. This circuit has a 555 timer at its heart and following components that aid its working:1N4148 Diodes Resistors in the range of Kilo and Mega Ohms. Capacitors at the range of Micro Farads and Nano Farads.A 9volt battery taking care of the power supply of the circuit.
Liquid/Water Level Indicator with Alarm using 8051 Microcontroller (AT89C51)
This article illustrates the construction and working of a liquid level indicator. Such an indicator is used in tanks to indicate the level of liquids and alert us when [[wysiwyg_imageupload::]]the tank is full. So by this circuit we can monitor the various levels of the tank and can avoid spillage of water and also we can configure our supplies according to the various levels of tank. Such module or circuit can be installed in big buildings where manual monitor of tanks is difficult and its indicator can be placed at some centralised place. Initially when the tank is empty LCD will show the message VACANT. As the tank starts filling up wire at different levels get some positive voltage, due to conducting nature of water. This voltage is then fed to their corresponding pins on controller. When level reaches to quarter level, LCD displays the messageQUARTER. On further rise of level, HALF and 3/4 QUARTER are displayed on LCD.
Accident Prevention and Security System for Automobiles
In this fast moving world, new technologies have been evolved for every second for our human life style improvement. There have enormous advancement in automobile technologies already and still to come. Because of these technologies, now we are enjoying the necessary comfort and safety.But there are lots of accidents happening now-a-days. It is because of increased vehicle density, violation of rules and carelessness. India ranks fifth in the road accidents over the world.We have the objective to minimize the road accidents due to above mentioned facts in real time using embedded systems platform in low cost. In our project, we proposed few concepts to minimize the accidents due to violating rules and carelessness. This project compromises of alcohol detector, mobile sniffing system, vehicle security system and an emergency system.