A new concept emerging from the first sketch.

01b. A book that senses left-hand pressure?

Updated on April 4, 2014.

The resistance variations in the CB01 sketch also uncover another set of possibilities, however. What would it be like to read a book that was capable of sensing the pressure of your left thumb? Could that kind of capability be used for anything interesting?

Here is the story of how this question emerged: in order to have something to play with, I finished the book CB01 and wrote a small program for an Arduino Uno microcontroller to read the value off an analog pin and send it to serial output. The pin effectively measures the resistance of the book (see the schematic to the left).

More specifically, there are two contacts in the book. One is a piece of aluminum foil over the top edge of the first leaf, and the other is the conductive headband. The conductive paint on the top edge forms a circuit between the two contacts, and the resistance of this circuit is measured.

Finally, I wrote a simple program in Processing to read the signal from the serial port, normalize it and draw the measured value together with a running average.

As expected, the book shows no consistency in terms of the value it provides when opened to a given spread. What it does, however is to respond to pressure around the contacts. This is notable not only when the book is open, but also when it is closed and laying flat.

(These two images show the Processing program on the computer screen superimposed on the original photographs. Note that the numbers refer to normalized resistance – grey is current value, yellow is floating average – but it seemed more reasonable to make the bar grow with pressure rather than the other way around. The pressure-sensitive action can be seen in the February 2015 video snapshot.)

In other words, there is now a kind of pressure-sensitive book to play with. My current idea is to locate a text-to-speech library where the reading speed can be controlled dynamically, and then make CB01 into a photo album with variable-speed narration.

Next: The circuits-on-pages approach.