Labview light beams and timers

[PT21]

Hi,

I'm a relatively new user of Labview so my apologies in advance for any suspect descriptions! 

I have 2 IR beams which I've connected to a NI cDAQ-9172 chassis and inputted them into an analogue input block (NI 9201) through ports 1 and 2. Using the DAQ assistant I have acquired the signals being given off by the 2 IR beams (8volts when broken, 0volts when intact). The IR beams will eventually be placed almost next to each other in a room so I can detect motion. I hope to be able establish which direction and area of the room a person is in depending on which IR beam is broken first. I want to beable to start timers depending on which IR beam is broken first. For example:

- If beam 1 is broken first, beam 2 will inevitably be broken second. Therefore I want timer 1 to start and the breaking of beam 2 to be ignored for a period of say 10 seconds.

- If beam 2 is broken first, beam 1 will inevitably be broken second. Therefore I want timer 2 to start and the breaking of beam 1 to be ignored for a period of say 10 seconds. 

Essentially I am struggling, with my limited knowledge to start a timer and ensure another signal input is ignored for a period of time.

If any further explanations are required I'll be happy to explain. Any help is really appreciated!

Thanks!

[EdMotts]

From your description, I wonder why you want to ignore the second trigger for 10 seconds.  It seems like you could have the first trigger set a boolean and record the time, and the second trigger does the same thing--when both booleans are true, compare the times and learn the direction of travel.

And just out of curiousity, are you using the Velleman IR transmitter/detector kit?  It doesn't matter, but I've played with one of those to detect when someone is coming to my cubicle behind my back.

Ed

[PT21]

Thanks Ed, I hadnt even looked at it from that perspective. Will give it a go.

Yeah it is a velleman kit, Ive been pleasantly suprised by its reliability actually!