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Head Mounted Magnifier

Motivations

My wife got me this amazing little gadget one year as more of a joke than anything. Little did she know that my overall "nerdiness," as she would put it, had evolved so much that I would not only wear this device but enjoy using it as well! But as with all great things, they could be a little bit better. Originally, the small lights didn't provide adequate illumination to be of much use. On top of that, each side was an independent circuit with its own batteries and switch. After a few usages, one side stopped working at all.

 

Re-Engineering Awesomeness

To be of any use, this thing needed to be able to really illuminate what ever I was looking at. To do so, it needed stronger lights. Each side contained a holder for two alkaline batteries rated at 1.5V each for a total voltage level of 3V DC. To increase this, I decided to run a couple of extra wires across the top of the visor connecting the two banks together forming one 6V battery pack. This also eliminated the need for two separate power switches. The next step was to replace the pair or bulbs with a few banks of ultra bright LEDs. I really wanted to keep the finished product looking as much like the original as possible, so I worked around the existing hardware and came up with the following schematic.



Using small foam pieces similar to those used in this project, I was able to fit four parallel sets of two series LEDs on either side of the head piece. Sixteen bright LEDs should surely be enough. The resistor value was chosen primarily because I had a bunch laying around, but estimating that each LED will drop a couple of volts, the resistors should provide a current of around 30mA to each LED bank or 7.5mA per strand. The actual current can be calculated as follows:

ILED = (VCC - 2 * VLED) / R1

The Build

The actual modification was pretty straight forward. New wires were soldered where they needed to be, and the LED banks were hot glued in place. Since removing the unused switch would leave a large hole in the left side, it was simply covered in electrical tape. I kind of wish I had painted the foam black before adding the LEDs as doing it now would undoubtedly get black paint on the LEDs, blocking some of the light from coming through.


The final product isn't the prettiest thing I have done, but it works quite well. Overall, this was a very successful project which greatly increased the useability of this head mounted magnifier.