Hi! I´m happy to share the images of my work. With the advice and help of my teenage son who is an electronics and RC hobbyist, I upgraded my project adding a dimmer device. This dimmer adds the ability to adjust the brightness of my table according to environment illumination and the opacity of the materials I´m working with. 

These are my materials and tools...

I decided to reuse a wooden frame from an old school work. We added a dimmer, a carpenter's square, vernier ruler, duplex cable, drill and a welding tool with the proper welding wire to the original supplies list.

As it isn´t easy to find the electronic supplies nearby we ordered them from an online electronics store and we needed to wait a couple of months for the arrival of these items from China.

We made the measurements and holes to adjust the dimmer, the power supply cable and to screw the acrylic sheet.

And then we assembled everything like the class but we glued an aluminum foil to the base and several LED stripes across the table to increase the lightened area. This addition of LED stripes makes necessary to weld the end of the rounding stripe to the first stripe on the base and this to the next one. You have to take care to face the correct polarity of the strips and to weld every strip in a proper way.

Finally, we assembled the Opaline cardstock (more opaque than regular Bristol cardstock) and the acrylic sheet by screwing them in their proper places.

And... Voilà, I´m enjoying my new DIY adjustable light table. 

Thanks a lot. I hope this will be helpful to others.

XOX Eréndira