Designing a home security system

[Samtheman1k]

Hi all,

I'm in the process of designed a 'home security' system that will be a custom built system consisting of a number of window/door Reed switches and a control centre, all managed by a PC running Labview with a PCI-6503 digital I/O card.   I was hoping that someone could help me with a few questions and also point out any issues that I may of missed!!!

The basic design is as below.

 

There will be a basic PC in the loft that is running Windows XP with Labview 7.  There will be a PCI-6503 Digital I/O card installed.  The aim is to connect a number (around 10) Reed switches to the 6503 that will all be attached to doors and windows etc.  The software will then monitor the status of the switches (open/closed) and report to a LCD display that is located by the front door.  My first question, is how do I connect the Reed switches to the 6503?  Do I just wire one end to the Digital Input and the other to the Ground? Or do I connect one end to a Digital Output and the other to an Input and then set the OP to HIGH and poll the Input.  If the Input is HIGH, then switch closed, if LOW then it is open?

The software will constantly monitor the status of the Reed switches, and then show the status to me in a number of ways.  If all switches are closed, then the green LED will light, if one or more are open then the red LED will light.  In order to control the LEDs, do I just connect the LED to a Digital Output (in series with a 1k resistor) and the other end to ground? 

There will also be a push button switch that will have some [currently undetermined] function, but I assume that I just connect this in the same way as the Reed switches?

There may also be a speaker, which I connect to the line out of the PC sound card and control via Labview. 

Finally, there will be a serial controlled LCD screen showing the status of each switch, that will be controlled with Labview and connected via the PC serial port.

Does the design seem right? Have I missed anything out?  Have I connected the switches & LEDs correctly?

Thanks!!!

[Tom.]

Hello,

LabVIEW will be able to handle everything you have covered. With regards to the digital I/O outputs you can attach an LED with the positive pin connected to the digital line and the negative to a corresponding GND pin. For the input you will need to simply connect a TTL signal into one of the digital lines, but ensure that when you have the signal low it is correctly grounded as opposed to unconnected so the signal doesnt 'float.'

You can use NI VISA to control your serial device and built in LabVIEW functions to play sounds or to use the system buzzers.

Hope this helps 🙂

Tom
NIUK