Showing posts with label system. Show all posts
Showing posts with label system. Show all posts
Luggage Security System
While traveling by a train or bus, we generally lock our luggage using a chain-and-lock arrangement. But, still we are under tension, apprehending that somebody may cut the chain and steal our luggage. Here is a simple circuit to alarm you when somebody tries to cut the chain. Transistor T1 enables supply to the sound generator chip when the base current starts flowing through t. When the wire (thin enameled copper wire of 30 to 40 SWG, used or winding transformers) loop around the chain is broken by somebody, the base of transistor T1, which was earlier tied to positive rail, gets opened. As a result, transistor T1 gets forward biased to extend the positive supply to the alarm circuit. In idle mode, the power consumption of the circuit is minimum and thus it can be used for hundreds of travel hours. To enable generation of different alarm sounds, connections to pin 1 and 6 may be made as per the table.
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Vehicle Electrical System Demonstrator
The ALD07 demonstrator is one in a range of self-contained fully operational auto electrical trainers designed for teaching basic electrical principles. Manufactured using original real vehicle components.Full operation of headlights, side lights, brake lights indicators and alternator via a speed controller can be observed.
The following vehicle circuits and systems are included:
Starting
Charging
Ignition
Lighting
Bidirectional Photoelectric System
Photoelectric
detectors are usually unidirectional, i.e. they are able to detect when
someone enters a particular area but not when leaves it. On the
contrary, a system able to detect movement in both directions could be
useful to control shops, rooms etc.
If installed in a shop it could allow to know if all customers entering
the premises have left them at the end of the day. Or, at home, it could
be used to switch on the light (or any other electric device) when one
enters the room and to switch off the electric device when he or she
leaves it.
Furthermore, the circuit is able to control the number of people, as it
switches off the electrical device only when the last person has left
the controlled area.
Read Full article[...]
detectors are usually unidirectional, i.e. they are able to detect when
someone enters a particular area but not when leaves it. On the
contrary, a system able to detect movement in both directions could be
useful to control shops, rooms etc.
If installed in a shop it could allow to know if all customers entering
the premises have left them at the end of the day. Or, at home, it could
be used to switch on the light (or any other electric device) when one
enters the room and to switch off the electric device when he or she
leaves it.
Furthermore, the circuit is able to control the number of people, as it
switches off the electrical device only when the last person has left
the controlled area.
Complete Room Securty System Circuit diagram
This simple circuit is called room security system circuit. The main purpose of this circuit is to secure your room in night. You need not any security guard. When any unwanted person wants to enter your room in night then this circuit raised alarm. On the other benefit, it is always activated on load shedding.
There are five separates parts in this circuit – regulated power supply, relay driver, door switching, alarm system and audio amplifier.
First section is regulated power supply. The output of IC 7809 is
regulated +9Volt which is converted from 9Volt unregulated power supply.
Capacitors are used for removing ripple. A full wave 9 volt transformer is connected in the input of this power section.
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There are five separates parts in this circuit – regulated power supply, relay driver, door switching, alarm system and audio amplifier.
First section is regulated power supply. The output of IC 7809 is
regulated +9Volt which is converted from 9Volt unregulated power supply.
Capacitors are used for removing ripple. A full wave 9 volt transformer is connected in the input of this power section.
The second part is relay driver. Q1 transistor is used for driving relay.
When the Q1 transistor is forward bias then the relay is ON and the
total circuit gets positive voltage from ac source. In the time of load
shedding relay is deactivated and the total circuit gets power from
6Volt Battery.
When the Q1 transistor is forward bias then the relay is ON and the
total circuit gets positive voltage from ac source. In the time of load
shedding relay is deactivated and the total circuit gets power from
6Volt Battery.
The third part is door switching. When C1 capacitor’s two terminals are short, transistor Q2 is reversed
biased. So Q2 transistor is OFF. When C1 capacitor’s two terminals are
open, transistor Q2 is forward biased. So Q2 transistor is ON. For this
reason IC UM66 is ON and it
generates music which is feed another two transistors Q3 and Q4. A
speaker is connected with collector of the transistor Q4 as circuit
diagram.
biased. So Q2 transistor is OFF. When C1 capacitor’s two terminals are
open, transistor Q2 is forward biased. So Q2 transistor is ON. For this
reason IC UM66 is ON and it
generates music which is feed another two transistors Q3 and Q4. A
speaker is connected with collector of the transistor Q4 as circuit
diagram.
Video Switch for Intercom System
Nowadays a lot of intercom units are equipped with video cameras so that you can see as well as hear who is at the door. Unfortunately, the camera lens is perfectly placed to serve as a sort of support point for people during the conversation, with the result that there’s hardly anything left see in the video imagery. One way to solve this problem is to install two cameras on the street side instead only one, preferably some distance apart. If you display the imagery from the two cameras alternately, then at least half of the time you will be able to see what is happening in front of the door. Thanks to the video switch module described here, which should be installed on the street side not too far away from the two cameras, you need only one monitor inside the house and you don’t need to install any additional video cables.
Video Switch for Intercom System Circuit diagram:
Along with a video switch, the circuit includes a video amplifier that has been used with good results in many other Elektor projects, which allows the brightness and the contrast to be adjusted separately. This amplifier is included because the distance between the street and the house may be rather large, so it is helpful to be able to compensate for cable attenuation in this manner. The switch stage is built around the well known 4060 IC, in which switches IC2a and IC2d alternately pass one of the two signals to the output. They are driven by switches IC2b and IC2c, which generate control signals that are 180 degrees out of phase. The switching rate for the video signals is determined by a clock signal from an ‘old standby’ 555 IC, which causes the signals to swap every 2 seconds with the speciļ¬ed com ponent values.
Naturally, this circuit can also used in many other situations, such as where two cameras are needed for surveillance but only one video cable is available.
Author :Jacob Gestman Geradts - Copyright : Elektor
Source : http://www.ecircuitslab.com/2012/02/video-switch-for-intercom-system.html
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