Best home made security circuit

[flemmard]

Hi guys,
can you please tell me some smart home made security circuits using PIC? I can think of alarms ...but i need some smart stuff to be included for my project.Any links ?

Thanks

 

[picbits]

Heres a couple of ideas ......

Use resistors inline with the PIR sensor contact and another resistor in the alarm panel - make a potential divider with a regulated voltage as the feed and then use the PIC A2D converter to monitor the voltage - a very effective anti-tamper circuit.

Look at the Dallas iButtons - easily readable by a PIC and incredibly secure. Good for door entry systems, alarm arm/disarm etc

PIC based temperature monitoring device - could be useful as a fire detector

Keypad entry system ?

That should keep you going for a couple of hours

 

[HarveyH42]

The best home security is a large breed dog and a shotgun. Second best would be cameras. Beyond that, you are mostly just spending money on something that won't really make much difference. I'm sure you've heard car alarms going off. How often do you see people rushing to check on their car, or even to turn the annoying thing off? Seems just as many people with alarms get ripped off, as those without. Home systems are about the same, even the ones who pay for monitoring service. Don't think you get an insurance break for building you own.
But everyone needs at least on hobby, so have fun with it. I use cameras and a regualr VCR. Got a MAX454, and will get around to hooking it up to a microcontroller to sequence through the cameras on my monitors. Also have a servo driven pan mount idea using two PIR sensors to lock onto people and keep them in the frame, sort of motion tracking. Basically, it will pan back and forth until a sensor detects, the pan that direction and stay until the sensor is clear, or the other sensor picts up something. If bothe sensors are active, the camera points in the middle. Have some issues to look into, the PIR isn't good in bright sunlight, or reflections. For my area, think it would be more of a night time function. What effect will an IR illuminator on the detectors? Also about a 5 second delay between detection and reset. Have to build it and see what good it will do.

 

[picbits]

Also have a servo driven pan mount idea using two PIR sensors to lock onto people and keep them in the frame, sort of motion tracking. Basically, it will pan back and forth until a sensor detects, the pan that direction and stay until the sensor is clear, or the other sensor picts up something. If bothe sensors are active, the camera points in the middle. Have some issues to look into, the PIR isn't good in bright sunlight, or reflections. For my area, think it would be more of a night time function. What effect will an IR illuminator on the detectors? Also about a 5 second delay between detection and reset. Have to build it and see what good it will do.

I'd stay clear of the PIR and go the ultrasonic route.

Basically have a 32 entry table on a PIC which holds a "base map" of the area to be covered. Move a small RC servo with the camera mounted on to one of 32 positions and compare the ultrasonic distance measured at that position to the base map. If it varies by more than a certain amount then you know there is something that wasn't there before. If all readings are wrong then you know its raining

You could also have it so it self learns its environment over a certain period of time and adapts to minor changes.

**edit**
Actually a better idea would be to use a single PIR to detect the inital movement over the larger area then scan with the ultrasound to find out exactly where the movement has taken place

 

[flemmard]

Heres a couple of ideas ......

Use resistors inline with the PIR sensor contact and another resistor in the alarm panel - make a potential divider with a regulated voltage as the feed and then use the PIC A2D converter to monitor the voltage - a very effective anti-tamper circuit.

Look at the Dallas iButtons - easily readable by a PIC and incredibly secure. Good for door entry systems, alarm arm/disarm etc

PIC based temperature monitoring device - could be useful as a fire detector

Keypad entry system ?

That should keep you going for a couple of hours

Hi, thanks....by the way, how do i do PIC based temperature monitoring device.I wish to do fire dectector using that.And one more, i wish to know any model water sprinklers during fire accident [this is just a model project]
Any other alternate ideas?
Thanks again

 

[flemmard]

I'd stay clear of the PIR and go the ultrasonic route.

Basically have a 32 entry table on a PIC which holds a "base map" of the area to be covered. Move a small RC servo with the camera mounted on to one of 32 positions and compare the ultrasonic distance measured at that position to the base map. If it varies by more than a certain amount then you know there is something that wasn't there before. If all readings are wrong then you know its raining

You could also have it so it self learns its environment over a certain period of time and adapts to minor changes.

Hi, sounds interesting ! Can i do human tracking using this?
I'm searching for some human tracking circuit[the person can have PIC with him]
and i wish to monitor him[position -accuracy not a concern] within home[kitchen or hall or bedroom].

 

[picbits]

Well for long range temperature measurement I would look at the Dallas range of 1 wire sensors on a 1 wire network and hook it up to a PIC to read the network. The PIC will know which sensor covers which area and can then signal the appropriate sprinkler to activate depending on which one was triggered. You could also monitor for lost sensors (destroyed in fire), cable short or cable open circuit which can happen in fires when the insulation and/or cable is melted through.