LCD and motion sensor

Im trying to get together a project with an lcd and two temp sensors. Thats not a problem. I want to use a motion sensor to turn on the lcd when it senses motion for a min. Im not sure how to do that.
Any sugestions

If you want to test that an input remains in the same state for a period then using millis() for timing is the way to go.

Save the value of millis() when the input goes into the required state and set a boolean to true. If the state changes then set the boolean to false. Each time through loop() test whether the boolean is true and whether millis() minus the start time is greater than the required period. If so then the input has been in the required state for the whole of the period.

See Using millis() for timing. A beginners guide

How would I wire the motion sensor
The ouput of the motion sensor is 3v the lcd is 5v. So I cant wire the lcd to the motion sensor

ok i think I got it
Instead of wiring the lcd to 5v I wire it to a digital pin

Be careful of the amount of current that the LCD requires. Most of the power that it consumes is likely to be its backlight which can often be controlled separately. Have you got a meter that you can use to measure its power consumption ?

Please post links to the data sheets of your LCD screen and PIR sensor. That will tell how to connect and control them. Your current code to read the PIR and control the display would also be useful.

I dont have any sketch yet. Im not exactly sure how to incorporate the motion sensor. I have now read that if i remove power to the display each time it turns back on it will have to initialize. I dont want to do that. Its a display on the wall when I walk up to it I want it to come on and display the pool temp. I was trying to extend the life of the display by turning off the backlight and the characters on the display.
Here is a link to the display
LCD Info
Here is info on the motion sensor.
Motion sensor info
I was thinking I could power the LCD from the arduino

I can't find much in the way of power supply requirements on the LCD in that data sheet. Also no mention of a backlight - does it even have one? Some displays may be powered off the Arduino, but it also depends on how the Arduino itself is powered.
The PIR looks simple enough. Just connect it to a digital pin.