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How to Build a Voltage Regulator for Caving Headlamps

Caving headlamps are essential pieces of expedition equipment. They are useful for illuminating the path when exploring a dark cave or other dark places, such as house crawl spaces. However, caution should be taken to properly ration battery power in headlamps. Many times, there is no built-in mechanism to regulate the voltage given the lamp from the battery, which means quick battery depletion and uneven lighting levels. If you have moderate circuitry assembly skills, you can build a voltage regulator to regulate light levels and to extend the battery life of your caving headlamp.

Things You'll Need

LVR2 light bulb voltage regulation kit
Soldering iron
4-AA battery caddy with leads
4 AA batteries
Small plastic waterproof housing with belt loop or clip
4 feet of red wire
4 feet of black wire
Drill with 1/8-inch bit
Glue gun

Instructions

- 1
  Organize all of your kit components in the order in which they will be used.
- 2
  Solder the components to the PCB circuit board using the schematic provided in the Resources link below. Pay special attention to the polarity of any polarity-sensitive components.
- 3
  Solder the leads from the battery caddy to the appropriate positive and negative power terminals of the PCB circuit board. Polarity is especially important because components will be ruined within 10 seconds of turning on the unit if polarity is incorrect.
- 4
  Solder the 4-foot red wire to the positive output terminal on the PCB circuit board. Solder the 4-foot black wire to the negative output terminal on the PCB circuit board.
- 5
  Add 4 AA batteries to the battery caddy.
- 6
  Place the battery caddy in the waterproof plastic box, followed by the attached PCB circuit board. The PCB circuit board needs to be on on top of the battery caddy so the on/off button is accessible without removing the battery caddy.
- 7
  Drill a 1/8-inch hole in the lid of your waterproof box. Feed the 4-foot black and red wires through the box.
- 8
  Seal the hole with hot glue from both sides using a hot glue gun.
- 9
  Solder the free end of the red 4-foot wire to the positive terminal of the halogen lamp. Then, solder the free end of the black 4-foot wire to the negative terminal of the halogen lamp.
- 10
  Test the unit by pressing the on/off button on the PCB circuit board. Pressing the button will result in different intensities of light between the on and off positions.

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