How do I make 2 or more objects light up when they come near each other, or get brighter, or change color? any ideas?

How do I make one or 2 objects(I have in mind small objects) light up when they come close to each other? or brighten or change color? Some one suggested proximity sensors. But then they would react when anything came close. He then suggested using magnets in some way so they would react to each other. I have a lamp that turns on when you wave your hand over it. If you place your hand close to the top of the container then slowly raise it the light will brighten, then dim as you lower your hand. Not sure if that is related to my quest, though I am interested in that also. Any ideas?

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Re-design8 years ago
Infrared light on top of each. Infrared sensor on each object. You will have to make them adjustable so that they only trip when they are close.
hardenbrook (author)  Re-design8 years ago
Thanks, Next weeks project investigating evryones suggestions. Very grateful. judith
freerunnin18 years ago
dry reed switches and magnets but make sure the magnets inside one object arn't too close to the dry reed switch else it wont work, then when they come together they light up, i have attached a picture of a dry reed switch, it has two metal pins inside a glass tube and when a magnet is near it the pins collide as they both pull in the same direction towards the magnet hope this helped
hardenbrook (author)  freerunnin18 years ago
interesting I will work with a friend on this, much more of a techy than I. I looked the sensor up on google. sounds good. I will let you know. thanks, judith
lemonie8 years ago
hardenbrook (author)  lemonie8 years ago
Great, I will have to have a friend help me with this. Hope we can look at it this week.
rickharris8 years ago
Find out what Hall effect ICs do.
geeklord8 years ago
I like the magnet idea, but if you want to see how close it is and not just an on or off, i think a hall effect sensor is the way to go.