Open video file if sensor reaches certain threshold value
What I'm thinking is that you could make a conditional statement. Below is a little a bit of pseudo code on how to possibly open said video from an SD card because there's no way Arduino would be able to store a video on it's own, let alone play good quality videos:

int dangerLevel = 500 (or however the shield reads the smoke level)

int smokeDetectorPin = A0

setup:

smokeDetected = analogRead(smokeDetectorPin)

loop:

if smokeDetected &gt;= dangerLevel:

open video from SD card directory or computer.



So in order to get a "video" from the SD card, you should check this website. Like I mentioned before, this is really primitive and it's probably not what you're looking for.

I found something very interest about the Arduino that I never knew you could do before and using composite display from a TV. Interesting and you can find that info here.

And lastly, to get a video from your computer or laptop, there's really no easy way. However, I did find two solutions that might be able to do this. First of all, and this may sound ironic since we're on an Arduino Stackexchange, you could use a Raspberry Pi (and this is the easily solution I can think of) though I believe your instructor prefers if you use the Arduino instead. Second, and this took me forever to find on the internet, you could use a third party software called "Gobetwino" and you can check out what that does here. I saw on YouTube video of a quick little demonstration of what it does. When the button is pressed, the video is played. That's conditional and you can do the same thing but for the smoke detector.