PaPiRus E-paper rating Machine

My internship was at RS – the leading global electronics distributor. As part of my role, I performed many different tasks and learnt many skills.

The most important contribution to the company was figuring out the E-paper project. The aim of the project was to promote E-paper where ultimately it would be shown at the Taiwan Maker Fair Exhibition.

To start, I read an introductory article on DesignSpark where I got some ideas on how to develop and integrate the E-paper at the exhibition.

The main idea of the E-paper project was to make it suitable for the exhibition. This included making the project fit for purpose so that visitors were allowed to interact and comment.

I did lots of research and had many ideas, but ultimately I chose to do a project called “the Capacitance Emoji Keyboard Rating Machine”.

An overview of the rating system

The objective of the design was to allow visitors at the maker fair to vote by pressing on an emoji keyboard using components brought at RS. The total votes was collected and shown on the E-paper, and the results of the voting were updated to Design Spark’s Facebook page every hour.

Image 1: The Capacitance Emoji Keyboard Rating Machine

Image 2: Modules in use: (Raspberry Pi, Arduino UNO with atmega328p, RFID NRF24L01+)

We used the concept of the capacitance sensor on the emoji keyboard. As image 3 shows, the emoji keyboard was made up of a single white piece of paper, where wires were connected to the bottom of the paper. When the user pressed on the emoji pattern, the corresponding emoji marked as pressed.

You may be curious to know how the capacitance on a white paper was being sensed.

This is all because of the electric paint. Paper is an insulator so electric paint can be used to build our conductive circuit.

We used the paint to draw a black circle with the wire connection on the back of the paper. When the user pressed the emoji, the capacitance of the paper changed dramatically just with a finger.

Image 3: Conductive paint on paper

Here, the NRF24L01+ RFID module is used for the communication between Arduino and Raspberry Pi. After the user pressed, the Arduino would send out a signal saying which emoji was pressed to the Raspberry Pi. Then, as image 4 shows, the Raspberry Pi would send the data to the Raspberry Pi 2 from the E-paper display via the mosquito server.