> A simple piano, as demonstrated in a video on Prelonic Technologies’ website [1], is created by first printing a set of piano keys onto a piece of paper using a standard laser printer. The back of that sheet is printed with a circuit layout using conductive carbon and then sandwiched with another printed conductive sheet and a small NFC chip in-between. Unlike Bluetooth which can be power-hungry (think of the limited battery life of your wireless earbuds) the NFC chip draws all the power it needs from a smartphone placed atop it. When combined with an accompanying app running on the smartphone, the paper piano can be physically played, producing notes through the device.
[1]: http://www.prelonic.com/products/PIP.html