need some help making an led light!

Ok, here is my situation. I've read a good bit on leds since I'm an avid caver. Use a petzl duo with the leds in it. But, what I want to do is. I've just bought me a metal detector and have started detecting. I would like to add an led to it to externally light up the screen in the late evening. I have included a pic of the detector head. I was thinking, all I have to do is find a small rectangular plastic box that snaps together, tap into the battery compartment which is on the top of the detector head just behind the garrett sticker seen in the pic, drill another hole in the plastic box for the led to stick out of, drill a hole in the lip on the detector head, that hangs over the screen. This way the led will go through the lip/sunshade and light up the screen. I can hadle all of that part, just don't know what to use between the batteries and the led itself. The detector runs on 4 AA batts. Most people recommend using alkalines instead of rechargables, although when the set that came in it run down I'll be trying rechargeables since I have lots of them(MiHh) that I use in my caving lights. Don't think this will be a concern with the led on the detector. Also, since the detectors batts will be supplying the led power, I don't think it will drain the batts very much will it? Would 1 normal led be enough? or maybe 2? I'm not sure. I'd also like to add a power switch on top of the box for the led. Like one of the rubber sealed ones. If anybody would like to explain to me with detail how to do this I'd appreciate it ALOT!!!!!!!!!!! I'm just not sure of the electronics part of wiring up the led. Hopefully someone will help me out!!!! Thanks for any help in advance.

If there was some way to attach a single led to the side of the lcd display on the inside of the head and attach that to the power lead (6 volts) you'd only have to use one resistor (2 ohms or so?). YOu'd have a light that always came on to side light the dispay. no external change necessary. Open it up and show us what the lcd display looks like.

just use two very thin flexible wires to feed the led from the power source. Do you have a multimeter? Do you have and have you ever used a soldering iron?

I've had it apart, I don't think there is room for an internal led. The part you see that shows the coin depth etc. is a very thin plastic screen cover, the lcd screen is mounted directly to the electronics board with a thin double sided sticky foam type strip lol. I'll take it back apart and take some pics to give you the best look at is as possible. It's gonna be hard to tell though I think. I would like to be able to put a switch in it somehow though for the light. I won't be needing the light very often and want to preserve the batts as much as possible. thanks and I'll get some pics late tonight and post them. This is gonna be a fun mod!!!! Just gotta figure out the best way to approach it!!

Oh yeah, I do have a multimeter and have done a little soldering, nothing major though. But I can hadle it as long as I don't have to solder anything tiny directly to the board, my brother can do all of that stuff if necessary though, he works in electronics. I'll get those pics asap!!

If there's any room anywhere in the unit, get yourself a simple rocker type switch to mount on the outside of the plastic shell anywhere it'll fit. Run pos + wire to this and then to the 5mm LED (inside or outside the shell). Between the LED and the switch, wire in a 2 ohm resistor. Done. Battery draw from a single 5mm led even at peak power, during operation of this device would be negligible. If left on it'd drain your batteries in about a week. If it were my device I'd try to mount a single 3 or 5mm inside facing the lcd screen and wire it in to the unit's main power so that the led is always on when the unit is in use.

Or just tape one of these to the handle pointed at the screen. $1 solution. 10 + hours of useful light, no drilling or soldering required.

What color led would work best with an lcd screen? I'm not sure about glare, if I have to put it on the outside. I'm gonna try to put it inside somehow, very little room though. I'm thinking red would probably be best, or maybe amber, I think white would probably glare most. Thanks for the resistor and switch info!!!! That is the main thing I needed to know, there is not a ground wire going to the led? Thanks again!!!!

yes, you'll need to complete the circuit so you'll need to ground the neg- led lead. LED's are very small and should fit jsut about anywhere. Experiment with different orientations until you're satisfied with the results.