Last year, a builder called me up and asked me if I can design a circuit for him to be fitted in his new construction,and my reply was yes, it can be done . That time I was busy in working on other project, and he wanted it in fifteen days time, so I refused him, since development takes time and it need to be throughly tested before putting into use.
Control system for modern house is based on the intel’s 8051 family of microcontroller.I am using Atme’at89c2051 microcontroller since this has two ports and is most suitable for our project. It’s stanby current is also low compared to 89c51.
Features:
1. Mail Notification
The control system for modern house is not a security device as compared to many commercial security devices available in the market. This project is a requirement of the modern multi- story buidings to have device like this . Multi-story buildings has an indivisual letter box fixed at the round floor.Some times, on weekends ,we donot go out for two to three days.We will never come to know that an urgent letter is lying in our letter box, could it be an appointment letter or a call letter for interview or something like that.
2) Power saving
We are also facing a acute shortage of electrical power these days, every now and then there is a power cut in some part of our city . If we could save little power from our house, it could be utilized else where, it could be a good contribution towards national development process.
1. Mail Notification
The control system for modern house is not a security device as compared to many commercial security devices available in the market. This project is a requirement of the modern multi- story buidings to have device like this . Multi-story buildings has an indivisual letter box fixed at the round floor.Some times, on weekends ,we donot go out for two to three days.We will never come to know that an urgent letter is lying in our letter box, could it be an appointment letter or a call letter for interview or something like that.
2) Power saving
We are also facing a acute shortage of electrical power these days, every now and then there is a power cut in some part of our city . If we could save little power from our house, it could be utilized else where, it could be a good contribution towards national development process.
3) Water saving
Half of the population in this world, donot get fresh drinking water, Some places you must have seen, that the water is over flowing, and is being wasted .It is a precious God’s gift to us we should not allow it to be wasted in this way. This also happens in housing societs where people sometimes leaves the water tap open and leave their apartment. Overhead tank drains out in no time. This creates troubles for every body in the society. I don’t blame them that they do it purposely, what I mean is such things do happen. So we must have something to alarm us if there is a flodding on the floor.
4) LPG leakage Or Smoke detection
Half of the population in this world, donot get fresh drinking water, Some places you must have seen, that the water is over flowing, and is being wasted .It is a precious God’s gift to us we should not allow it to be wasted in this way. This also happens in housing societs where people sometimes leaves the water tap open and leave their apartment. Overhead tank drains out in no time. This creates troubles for every body in the society. I don’t blame them that they do it purposely, what I mean is such things do happen. So we must have something to alarm us if there is a flodding on the floor.
4) LPG leakage Or Smoke detection
LPG leakage is also considered in my project.
• So, it saves huge electric bills by saving electricity, lights are only switched ON during night times or when visibility is poor.
• It speakes out voice message at a regular interval that a new mail has arrived.
• It sounds an alarm whenever a flooding is detected on the floor.
• It sounds an alarm when gas leakage or smoke is detected.
• It speakes out voice message at a regular interval that a new mail has arrived.
• It sounds an alarm whenever a flooding is detected on the floor.
• It sounds an alarm when gas leakage or smoke is detected.
Circuit explanation:
AT89c2051 is a 20 pin microcontrolles .it has two ports port3 and port1. Port 1 from pin number 12 to 19 (8bit). All the port pin logic state is high except pin number 12 and 13 . pin number 12 and 13 are analog pins for comparator. Out put of the comparator is available internally at pin number p3.6. so pin p3.
AT89c2051 is a 20 pin microcontrolles .it has two ports port3 and port1. Port 1 from pin number 12 to 19 (8bit). All the port pin logic state is high except pin number 12 and 13 . pin number 12 and 13 are analog pins for comparator. Out put of the comparator is available internally at pin number p3.6. so pin p3.
6 is not available out side. Pin number 12 and 13 are connected with the external pull up resistor r9 and r10 in order to make them digital i/o Pin number 2 and 3 are connected with the switch as I said earlier logic state of all the port pins are high pressing of these switch will detect low logic on that pin as other side is connected to ground (-ve).
SW1 is used to switch on /off the system SW2 is used to silence the alarm. Gas sensor is connected to pin number 6, please note that gas sensor should have relay with normally open contact, in order to connect to this circuit. Refer to it,s documentation before buying the gas sensor. Please note that gas sensor is not the part of this circuit you have to buy it separately at additional cost.
Ic3 P89021 is a one time programmable(otp) chip where messages are stored. This is 21 second speech ic where total of 12 messages can be recorded on eight different locations, but total duration should not be more than 21 seconds. Recorded messages can be played back by setting the trigger pin 10 & 11 high, making these pin low will stop the message, Setting these pin high will repeatedly replay the same message.
Ic lm 386(IC4) is an audio amplifire . Audio output from speech ic pin no 7 cout is coupled to this ic on pin no 3 through VR2 volume control and C10. Amplified output from pin no 5 drives the speaker through capacitor C12. R8 and c11 corrects the tone. R7 and c9 provides decoupling for noice . Speaker is connected to CON1 connector.
Ic3 needs 3.3v operating voltage .R5 is a voltage dropping resistor, D5 is 3.3v zener diode and C7 is a filter capacitor. These components will always maintain the voltage to3.3v at pin number 9,12 of IC3. capacitor C8 is a feed back capacitor., VR1 variable resistor connected to pin 8 of IC3 performs the sampling rate adjustment .
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