Read the buttons

What this example shows

All 16 pads are read every 50 ms and printed as a 4x4 map in the Serial Monitor at 115200 baud: X for a pressed pad, . for a released one. The LEDs stay off.

The example code

This is examples/ReadButtons/ReadButtons.ino from the pinned library, unchanged.

Select Board

ReadButtons.ino

/**
 **************************************************
 *
 * @file        ReadButtons.ino
 * @brief       Example showing how to read all 16 buttons on the Inputronic Grid.
 *
 *              Reads all 16 button states every 50 ms and prints a 4×4 grid
 *              map to the Serial monitor. Pressed buttons show 'X'; released
 *              buttons show '.'.
 *
 *              Hardware wiring:
 *              - Connect Inputronic Grid to host via Qwiic / I2C
 *                (SDA, SCL, 3V3, GND).
 *
 * @authors     Josip Šimun Kuči @ soldered.com
 ***************************************************/

#include <InputronicGrid.h>

InputronicGrid grid;

void setup()
{
    Serial.begin(115200);
    while (!Serial)
        ;

    if (!grid.begin())
    {
        Serial.println("Inputronic GRID not found. Check wiring.");
        while (1)
            ;
    }

    Serial.println("Inputronic GRID ready.\n");
    grid.clearLEDs();
}

void loop()
{
    Serial.println("+---------+");
    for (uint8_t row = 0; row < 4; row++)
    {
        Serial.print("| ");
        for (uint8_t col = 0; col < 4; col++)
        {
            Serial.print(grid.readPad(row, col) ? 'X' : '.');
            Serial.print(' ');
        }
        Serial.println("|");
    }
    Serial.println("+---------+\n");

    delay(50);
}

Expected result, with nothing pressed:

Serial MonitorAutoscrollShow timestampNewline115200 baud

Message (Enter to send message to the board)

Inputronic GRID ready.

+---------+
| . . . . |
| . . . . |
| . . . . |
| . . . . |
+---------+

A new map follows every 50 ms. While you hold a pad, an X takes the place of its .: the top line of the map is row 0 and the first character in a line is column 0. When the board does not answer, the sketch prints Inputronic GRID not found. Check wiring. and stops.

Functions used

InputronicGrid(uint8_t address = INPUTRONIC_GRID_DEFAULT_ADDR)returns InputronicGrid

Creates the driver object for one GRID. The example declares it as InputronicGrid grid; with no address, so it uses the default 0x30.

ReturnsThe driver object.

Parameters

Type	Name	Description
uint8_t	address	I2C address of the board. Optional, 0x30 (INPUTRONIC_GRID_DEFAULT_ADDR) by default.

grid.begin(TwoWire &wire = Wire)returns bool

Starts the I2C bus with wire.begin() and checks that the board answers on its address.

Returnstrue when the board acknowledged on the bus, false when it was not found.

Parameters

Type	Name	Description
TwoWire &	wire	The I2C bus to use. Optional, Wire by default.

grid.clearLEDs()returns void

Turns all 16 LEDs off. It is the same as setAllLEDs(0, 0, 0).

ReturnsNothing.

grid.readPad(uint8_t row, uint8_t col)returns bool

Asks the board whether one pad is pressed right now, by its place in the grid. Each call sends the board a short I2C request and reads its one-byte reply.

Returnstrue while the pad is pressed, false when it is not.

Parameters

Type	Name	Description
uint8_t	row	Row, 0 to 3, top to bottom.
uint8_t	col	Column, 0 to 3, left to right.

Putting it together

setup() waits for the Serial Monitor, checks the board with begin() and turns the LEDs off. Each pass of loop() calls readPad() once for every row and column and prints the result as one line per row.

To read all 16 pads with one request and reply instead of sixteen, the library also has readAllPads(), which returns a 16-bit mask with bit row * 4 + col set for each pressed pad. No example uses it at this commit.

SourceOpen the verified Arduino exampleView the exact source used by this page.examples/ReadButtons at 399b832