Wi-Talk! is a communication tool. It’s an object for exploring new models of digital-physical communication at local scale.

The tool is a led screen to hang from the window. Citizens can sent it text and the message is visible from people passing by in physical space.

Wi-Talk! is a tool for making digital communication visible and localized in the physical space. Facades are talking walls, that tell citizens what people living behind think and care about.

Wi-Talk! is basically composed by a led screen connected to an Arduino board.

The screen is made by a led strip (5m, 60 led/m).

The basic screen requires a minimum of 8 lines of led for the visualization of the text. So the 5 m strip have been cut in order to have 8 led strips with 37 led each. The strips have been connected each other welding cables (that connect 5v, data and ground line) and a power supply.

The screen works with an Arduino board that send the text, using the Neomatrix library.

The first led of the screen is linked to the Arduino board and to the extra power supply:

• Data line is connected to a pin in the board,
• 5V line is connected to positive line in the power supply
• Ground line is connected to ground both in the board and in the power supply.

In the code of the library user can define the mode of visualization of the text: mode of entrance, speed of the scrolll, color of the text, brightness of the light, etc.

#include <Adafruit_GFX.h>
#include <Adafruit_NeoMatrix.h>
#include <Adafruit_NeoPixel.h>
#ifndef PSTR
#define PSTR // Make Arduino Due happy
#endif

#define PIN 6

Adafruit_NeoMatrix matrix = Adafruit_NeoMatrix(37, 8, PIN,
NEO_MATRIX_TOP + NEO_MATRIX_LEFT +
NEO_MATRIX_ROWS + NEO_MATRIX_PROGRESSIVE,
NEO_GRB + NEO_KHZ800);

const uint16_t colors[] = {
matrix.Color(255, 255, 255), matrix.Color(0, 255, 0), matrix.Color(0, 0, 255) };

void setup() {
matrix.begin();
matrix.setTextWrap(false);
matrix.setBrightness(30);
matrix.setTextColor(colors[0]);
}

int x   = matrix.width();
int pass = 0;

void loop() {
matrix.fillScreen(matrix.Color(0, 0, 0));
matrix.setCursor(x, 0);
String msg = “HALLO WORLD!”;
int l = msg.length() * 6;
matrix.print(msg);
if(–x < -l) {
x = matrix.width();
if(++pass >= 3) pass = 0;
matrix.setTextColor(colors[pass]);
}
matrix.show();
delay(100);
}

REFERENCES

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sealed-ws2812-rgb-led-strip/

Wi-Talk! is a project of IaaC, Institute for Advanced Architecture of Catalonia
developed at Master in City and Technology, Physical Computation in 2015 by:
Students: Chiara Dall’Olio
Faculty: Ángel Muñoz