Quote:
Originally Posted by obelix
3) Next approach. I purchased LightWedge backlight ($25, Barnes and Nobles, http://www.lightwedge.com/prod_paperback.html). The light is more "scattered" and gives much more comfortable reading (though the illumination is not very uniform). The bad things are:
i) The wedge does not fit the reader size ii) it requires 4 AAA battaries (to heavy) 3) light is not stabilized and adjustable.
So I modified the LightWedge the following way:
1) Cut the wedge to fit the reader screen
2) Made a hole to get 2 LED according to new size
2) made the box with Li-ion rechargable battery with the FAN5607 chip, potentiometer and the switch. |
I have just finished a "Do It Yourself" project
I have no means of purchasing LightWedge for reasonable price.
So I have manufactured one at home.
I glued (using tape that is sticky on both sides) a piece of 5mm thick plexiglas
to a board.
Then I fixed a piece of wood next to the plexiglas.
Next I glued a very coarse sandpaper to a flat surface.
I have put the plexiglas glued to the board on the sandpaper so the wooden spacer was sliding on the surface next to the sandpaper. By sliding the plexiglas back and forthe I was able to grind an even and uniform wedge.
It takes about an hour. Next I used finer sandpaper, then finer, then very fine, then 1200grit to make the sufrace very smooth. I finished the surface with a very fine polishing paste (purchased in a car-shop accesories for "paint restoration" on a car)
If you are interested in some photos, please send me a private message or reply to this thread.
Quote:
Originally Posted by obelix
The illumination is not very uniform, but reading is much more comfortable than with any of other sources. Almost that comfortable as with REB 1100 (b/w LCD with back illumination)
|
now comes the interesting part of my project.
I went to a cheap "chinese" store - selling low quality shoes, clothes, flashlights, knives, toys and other assorted junk
I have purchased a flashight with 21 white led diods for cca $7. (yes 21 leds purchased in a store selling electronic parts cost more, plus I have holder for three AAA batteries
)
I have used my beloved "dremel" tool (actually manufactured by Proxxon
) to cut the printed circuit board with LEDs to a thin strips. Then I glued the LEDs to a little thin piece of board one segment next to the other. I used a hot glue gun. I have soldered all LEDs so all plus contact are soldered to a single long wire and all minus contacts are soldered to another wire.
When you place those 21 leds next to each other they cover a distance of 13 cm (the height of the display is 12cm) with a nice bright even light.
I have glued that LED assembly to the side of my homemade wedge and I got a very nice even frontlight. The original LightWedge uses just three LEDs (or is it two?), and I can imagine the light is uneven.