DIY Multipurpose Copyholder !!

Well the idea of this DIY came to my mind when i wanted something to hold my papers onto a stand where i not only can easily read it but also have a line marker to know where i was earlier.I am an electronics hobbyiest and is working on electronics projects where you have to consult datasheets all the time for the particular components.Thus the idea of a "COPY HOLDER" came to mind.I didn't had this already or ever thought of buying one. I found a copyholder in a dumpster dive and it was in a good condition except the stand was broken and needed a fix.

Then i thought why not add a strip of LED lights to it so that it will very handy in low room lights or when working at night times.I also added a NE555 based brightness control circuit to it so that i can adjust the brightness according to the taste of my eyes and it also has a basic 5V USB outlet so that you can charge your mobile phones,etc on the go.The copyholder back has also been provided with a plastic container box that can be used to place your mobile phone.etc while charging or any other stuff you like to.

You can also store secret components or stuff in the back container and it can also be used to organize your stationary.

The copyholder can be directly powered with solar panel and thus can charge your mobile directly through solar panel!!

Hope you like the DIY and enjoy trying it,if you need one!!

Luckily i got this copyholder from  a dumpster dive with broken stand hoping we can do something useful with it.

For the base of the LEDs,i used this combination of plastic IC holder and a file carriage.
I cut them in length exactly to the width of the copyholder to fit nicely!!

Then I drilled 20 number of  2.5mm holes for LEDs to be fixed just partially to the bottom of their base.

Then all the 20 LEDs were fixed onto place and soldered in combination of 4 in series first and then 5 parallel combinations of each 4-series ,thus total 20 LEDs.
A power cable is then connected to feed the 12v supply.

Two "L" shaped metal clips were used to mount the LED strip onto the top of copyholder.
They were first angled a bit to suit the inclination on the front face of the copyholder.
Two holes were then drilled on top of the copyholder and the strip was then mounted. 

Simple LM7805 linear regulator with a couple of filtering and coupling capacitors are used to derive regulated 5V for the USB power rail.

A superior method of dimming LEDs is to use Pulse Width Modulation (PWM). With PWM strings of LED bulbs can all be driven with the recommended forward current, with the dimming achieved by turning the LEDs on and off at high frequency - so fast the human eye cannot see the strobing effect. The longer the on periods are relative to the off periods, the brighter the LEDs will appear to the observer.

Duty Cycle is a percentage measure of the time that the LED is physically on. If, for example, the LED cycles ON for 9/1000 of a second, and then OFF for 1/1000 of a second, the duty cycle is 90%: 90% of the time it is ON, and 10% of the time it is OFF. Therefore, the intensity of the light will be approximately 90% of its undimmed level.

The easiest way to achieve this high frequency switching is to use a 555 timer integrated circuit (IC) - one of the commonest and most versatile ICs ever created. The circuit shown is designed to be used as a dimmer for LEDs.

This dimmer circuit cannot be used to turn the LEDs all the way off or to full brightness. In fact it operates within a duty cycle range of 5%-95% as the potentiometer (labelled P1) is turned from minimum to maximum. (By using germanium diodes in place of the two IN4148 signal diodes this dimming range can be extended to go from 1%-99%.)

The circuit was then enclosed in an enclosure (u may laughing at the blue rounded enclosure i have used here).
Also the mount for the female USB socket is made on a veroboard PCB and was then mounted on the copyholder.
A DC jack is then provided to feed 12v to the circuit either through a wall adaptor or a 12v solar panel.
And also all the flying wires were then cable tied.

I used a tupperware plastic container and mounted at the back so that you can put all your stuff in it.
It can also be used to put your mobile phone while charging it.

For powering the device you can directly connect it to a 12v wall adaptor or 12v a solar panel.
Thus continuous power all the time for the copyholder and also charge functionality for your gadgets using solar power.