Step 1: Tools and Materials
wire strippers (optional but very helpful)
tin snips (again, optional but very helpful)
helping hands (helpful and again optional)
drill / drill bits
led (preferably high brightness.)
resistor (see step 2 for choosing the right one)
9V Battery holder
toggle switch or push on push off switch
circuit board (optional but helpful)
Step 2: Choosing Your Things
1) do you want a a lot of room to do a lot of awesome stuff?
2) do you want high quality plastic that wont crack when you drill it?
3) do you want a large battery pack that can hold all your dream headlight electronic components components?
4) do you want a headlamp that seams like it was built for taking apart and making more awesome?
5) do you want a large reflector that leaves a big hole of light write where you want it most?
I was able to get all of these in my headlamp (even the big hole in the light) so I consider my self pretty lucky. Although my headlamp is not a running, backpacking, ultra high tech lamp with multiple settings and dimming at the push of a button. It was more of a spelunking/construction headlamp with two settings on and off. not to mention it was old, and therefor, simple. Easy to take apart and gut.
Now along the lines of choosing an LED.
1) what shape of LED do you want
2) what color of LED do you want (white for brightness or red to preserve night vision.)
3) how many LEDs do you want.
I got a flat square led for its ease of mounting on a circuit board. My led was white because I wanted the clean white light. I only got one led.
Choosing a resistor.
You may ask why you need a resistor, well it protects you led from the evil amps that come to destroy it. Also it can help preserve your battery life. To find the right resistor I use this calculator . It calculates the MINIMUM ohm's needed keep your LED happy when electrons com zooming into it. There is no problem with using a more powerful resistor. Than you need. All the specs that you need to plug in should be on your LED packaging. if using LEDs in a series ( one right next to the other) add up the forward voltage NOT the amps.
Step 3: Gut the Lamp
Step 4: Make the Holes
Step 5: Place, Solder, Repeat
Step 6: Testing and Troubled Shooting / Closing Remarks
If your light doesn't turn on
look to see if there are...
1)any bad connections
2)any wire points or solder bridges (the things used to connect wires on the Circuit board) that aren't suppose to be touching are touching.
If your light won't turn off...
Look to see if there is a short circuit between the wires on the switch.
If you light won't adjust...
Look to see if there is a short circuit between the wires on the POT
If your light sparks or speaks to you...
call the ghost busters and check for steel wool on the 9V battery leads.
Now enjoy your new headlamp with brightness control! If you have any questions or have anything I need to add just leave something in the comments.