Need expert advice for unusual LED circuit.

[PRN.JRA]

What I am trying to construct is probably exceedingly simple, yet currently outside my ken. I am seeking advice concerning an unusual circuit concept. I am looking to build this device as simply and cheaply as possible, because I will need to construct a large number of these. So here is what I'm trying to build:

An isolated circuit primarily consisting of an LED and an EMF detector. When the circuit is powered on, the LED lights up. This LED has a tiny antenna near it that detects EMF disturbance. When the EMF field is disturbed, the LED will turn off. The LED will then stay off until power is cycled on the circuit. Once power is cycled the circuit resets and the LED lights up again.

I understand I could use something like a FET to do this for the EMF detection, but I prefer not to do this with a FET if possible. I say that because buying a lot of Fairchild FETs to create an array the size I need would be expensive. So if there is another way to do this without a FET that would be great. I have no idea how to do the component level circuit logic beyond that because I am an IT guy not an electrical engineer. I do plan to bus power the array btw.

Any ideas or prototype circuit designs for this concept would be greatly appreciated. The simpler the better! Thanks for your time.

[pebe]

Can you define the EMF disturbance you are looking for?

[PRN.JRA]

What I am trying to construct is a variation of something like this in mass multitude:

http://www.eskimo.com/~billb/emotor/chargdet.html
http://amasci.com/emotor/fetdet1.gif

If I understand things correctly, in that design the LED lights up when the FET is switched by EMF disturbance. Let us consider this device "1 pixel". I want to create a grid like array of "pixels" that consist of LEDs individually triggered by nearby EMF disturbance. I would want the EMF detection to be sensitive enough that when someone places their finger near a respective LED "pixel"'s micro-antenna it would turn off that individual LED. So in a way you could say I'm making a drawing tablet of these LED pixels to be drawn on by using one's finger. The complexity lies in the fact that the LEDs need to be all lit initially, and turned off as they are triggered independently, and then stay off until power is cycled on the entire circuit.

I do not know if a FET such as the one described in the article I cited is powerful enough to detect a single finger's nearby presence to it, in enough magnitude to trigger the transistor switch. Then there is the issue of individual EMF antenna placement in such a way that the LED itself does not trigger its own self off. Obviously my electrical engineering knowledge is only rudimentary. That's why I'm seeking expert advice on this project. There may very well be a far simpler way to construct this circuit application than I am currently realizing. I just need to create an array of lit LED pixels that can be independently turned off by the presence of a nearby finger's EMF disturbance.

Perhaps I could use some sort of insulative inhibitor around each independent antenna in order to severely limit the detection range of each individual FET. I am more confused about how the component logic would work to disable a previously powered LED, and then keep it off until the circuit resets. This is something I don't know how to do but is probably exceedingly simple for actual electrical engineers.