LED Bookmarker +table Lamp (with Brightness Control)

This is a DIY reading light . I call it " LED bookmarker".

Hi,

I have created a bookmarker that helps us in reading the books in dark .It an used as table lamp , shared, it is so bright that two people can read read books comfortably (when used with full brightness)

this bookmarker has some LEDs to give light . it is big when compared to other book markers ,but worth it.

I got this idea when i started reading a book and suddenly lights went off , there was a bookmarker sitting just in the middle of two pages doing nothing!! , i wanted it to help me.

LED bookmarker can be used in hostels , while camping outdoor or on the bed , when you dont want to disturb others.

its brightness can be controlled.

Step 1: Things From Collections

materials:

plastic sheet / metal sheet (any sheet for bookmarker )
LED strip , pure white( should be bright enough and slim )(I prefer the one without waterproof coating)
old mobile phone with battery or any battery pack or AA or AAA rechargable batteries
switch
potentiometer of least value available ( i have used 1k)
wires
single strand wires ( copper wire with little spring action and alumminium wire)
resistors
m-seal (something like sugru )
cellophane tape

tools;

soldering iron
wire strippers
blade
hack saw
multiplier
glue gun
screw driver
pencil
scale

Step 2: Start With Bookmarker

decide the length of the the book marker, breadth can modified later also.

decide the material of the book marker, plastic or metal or paper.

metal ones can be made from aluminium beverage can .

I have chosen plastic.

cut the LED strip to the length of the bookmarker.(read the next step before cutting)

cut 2 strips of that length.one for each side of the bookmarker.

Step 3: Flaps

cut 2 strips of cardboard to make flaps that prevent light shining directly to eyes.

stick this flaps to the bookmarker as shown. it should be foldable.

Step 4: Working With LED Strip

most of the LED strips work with 12V power supply , small battery packs don't give 12V so we need to modify the LED strip a bit according to the battery that has to be used.

I have used 3.7v li-ion battery (from old nokia mobile).

LED max voltage is 3.2v (in my case)(in most of the LED strip ,LEDs have max voltage around 3v).

In LED strips ,3 LEDs and a resistor are conected in series , this group is conneced in parallel with other similar groups to form strip.

To run these LEDs with 3.7v battery i have removed all the resistors by desoldering . and connected all the LEDs in parallel .

[if you want to run LEDs in 9v supply replace all resistors with a short (only for LED strip which has 3LEDs in group).]

Step 5: Preparing Battery Holder

i have already used this mobile for some other project .

so remove all apart then , electrically isolate the battery connectors from the mobile circuit.

this can be done by cutting the connections around the connectors using blade( don't cut the board).

draw some wires from the connectors.

i have cut off the unwanted part of the mobile body.

and cut the circuit also . but i haven't bcz it may be useful for other projects.

Step 6: Control Circuit

the 3.7v battery gives around 4v when fully charged , so i have to droped this extra 1v in a resistor. totally two strips of LED consume about 400mA . so r=v/i , r=2.5ohm in my case. i have also added a pot in series to control the brightness of LEDs.(all of them in series with battery and LEDs).

I made a hole in the mobile body to take out the knob of pot.

fit all the components inside and glue it up.

give the potentiometer a knob. by turning the knob the brightness of the LED can be varied .

use pot of 500E or lesser to get good (fine)control.(i have used 1kE which is a little coarse)

if wanted ,take connections for charger pin.