the way the smell detector 3000 works is first it has a tube like a antenna on the top of the device it will get the smell inside and a proceeder will detect all the different smells in the air and show it on the bottom screen after you press the on button and press find, then you will select the food that you want, like pancakes and on the screen on top it will show a GPS showing your location the streets and the location of the source of smell(the food store) then bellow this it will show the name of the food, its location(25th street) and how much it costs(30 RMB) and on the left of that there will be a compass that will show the direction of the food with your device as the center, and also when you get closer to the food store a bit in radio will start to beep more rapidly(this only starts after you get in a ten meter radius of the store because I figured the GPS won’t show to much when you are very close). after your done you press the reset button for a second use. I got the sound idea from the metal detector
and I got the whole things idea from ghost busters ghost detector