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home automation using avr

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animax

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hi
i am designing a home automation system using an AVR an an IR sensor.
can anyone please help me in designing the circuit??

is it necessary to use a filter???
 

The "automation" is very generic description, you have to explain what you have in mind to build, what will it sense and what will it control.
IR sensor to do what?

Alex
 

here "automation" is used for automating only lights and fans.
the infra red(IR) sensor will sense the person's incoming\outgoing and will send a signal to the avr to take respective actioni.e. switching on\off the power through a relay.
 

no no..
it's not remote controlled.The ir sensors will be fitted on either sides of your room gates. when a person enters the room, the ir signal will break and this will be used to detect whether a person is going inside a room or coming out of the room.

there is nothing remotely controlled
 

How do you plan on understanding if someone is leaving or entering? Having two sensors a little further off each other would help. Then you could sense which one is broken first and then which one to understand if the person is entering or leaving.

---------- Post added at 22:59 ---------- Previous post was at 22:56 ----------

You can have an IR transmitter at one end and a receiver (eg PNA460x, TSOP1738, etc) at the other end. If the IR LED is on all the time, the receiver will give a signal (0 or 1) depending on your circuit. When a change of state occurs, you'll know that the IR light has been broken. You can use external interrupt to sense this. You can use interrupt-on-change.

As we go on, I'll try to help along and describe more, as much as I can.

Hope this helps.
Tahmid.
 

yes..
that's what i was planning to do. 2 ir sensors at a distance of about 1' from floor and separated by 1" or 2".
 

So, first you need to get your IR transmitter working. You can use the AVR to generate a 38kHz signal.
 

but is it necessary to add a filter to the avr circuit???
 

a friend of mine suggested that i should use a low pass filter in my circuit..:roll:

i do not know the reason; so i thought of asking it on the forum..
is it really necessary to use any kind of filter in that circuit????
can't it be done without a filter??:-|
 

The filter depends on your circuit. Maybe you can do it without a low pass filter. For one thing, you need to filter the power rails.

Using one pin of the AVR, sense whether there is an signal from the IR sensor. When there is no signal from the sensor, then the IR beam has been broken.
 

No need of filters, Just get the signals from the sensors and control the lights.
no need of 38khz frequency generation if you are using IR photo diodes,
you need 38KHz or 40 KHz for some TSOP IR sensors, these sensors come with 38KHz demodulator
But you should avoid TSOP because some new TSOPs comes with a PWM that cancells constant 38KHz signals
 
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    animax

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here "automation" is used for automating only lights and fans.
the infra red(IR) sensor will sense the person's incoming\outgoing and will send a signal to the avr to take respective actioni.e. switching on\off the power through a relay.

Why dont you use PIR sensor?
 

because i already have a pair of IR sensors with me;so there is no need to add further cost to such college projects..:-D

but will a PIR sensor work better than IR sensor in my case???
if its functioning is somewhat better than the IR sensors , then i will consider that option also...
 

it is passive infrared sensor. it measures infrared light radiating from objects in its field of view.
it is used in motion detection.
 

    V

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because i already have a pair of IR sensors with me;so there is no need to add further cost to such college projects..:-D

but will a PIR sensor work better than IR sensor in my case???
if its functioning is somewhat better than the IR sensors , then i will consider that option also...

I have not used PIR, but I have seen many similar applications like yours using PIR sensors.
 

actually this home automation project is for my sophomore year training project..
so i dont wish to stress 2 much on its advancement..

just a simple IR sensor will be sufficient
but i will consider your advice for my further projects..


regards,
animesh
 

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