Loublet Schematic

The primary focus should be on using the appropriate drivers for the tablet. This makes it a USB host. As seen in the video, light can be a medium of communication between the tablet and the microcontroller. A photo diode or photoresistor is what is needed here and this should be pressed against the Lcd.

Building a touch sensing capability can help in providing communication between the microcontroller and the tablet. Capacitive touch Lcds function by sensing the capacitance changes on the Lcd. In this case, a large conductive brass plate is used to simulate touch. The surface area of the conductor used here to simulate the touch sould be large.

Testing can be done by touching the scrren with a wire and holding the other end. This may not work. This is made to work by sticking a piece of aluminum foil on to the Lcd and connecting the free end to the pin that is available on the arduino. The video shows the working of the capacitive touch Lcd. The setup is quite fragile and a little more schemary could improve its reliability. Thus the capacitive touch Lcd is done.

Generally for connecting an LCD display to an Arduino using 7 strands, it usually breaks the leg that has any projects that remain few ports to be used. But there is a way, using an IC 74LS164 (8-bit serial shift register), a resistor and a diode, but its not just hardware, you have to use a library.

This Arduino library for connection of 2-wire or 3-wire using HD44780 compatible LCD display via shiftregisters. This schema is considered "deprecated", but its worth testing.