Develop Mono apps in Arduino IDE

Hi all! As the summer is coming to an end, we would like to show off the possibilities of using Arduino IDE and Mono together. If you develop Arduino software or intend to, this update is for you! If you do not know about Arduino, then feel free to skip this writing or read on anyways.

We feel the need to get the word out. We have a working development environment for Mono, integrated directly into Arduino IDE. Everyone familiar with Arduino's setup and loop scheme, should know you can use this to create Mono applications.

Adding Mono support in Arduino IDE

Arduino added a great feature to their version 1.6 of the Arduino IDE; the Board Manager. This tool allows you to easily add extensions to the IDE, making it very quick and simple to build Arduino sketches for Mono.

If you find the examples below interesting, we really encourage you to take a look at our Arduino Getting started guide on our developer site.

Quick Examples

Just to demonstrate how quick and agile our APIs are inside the Arduino IDE, we shall look at some very brief examples, starting with the basic ones.

Display text on the screen

First, we shall see a simple sketch that shows a static text on the screen. The code below adds a TextLabelView object and initializes it inside the setup function. We also give the text a neat color to make it appear more Arduino like.

#include <mono.h>

mono::ui::TextLabelView lbl;

void setup()
{
    lbl = mono::ui::TextLabelView(
        mono::geo::Rect(10,10,156,70),
        "Say hi through the\nArduino IDE"
    );

    lbl.setText(mono::display::TurquoiseColor);
    lbl.show();
}

void loop() { }

Toggle a button

Now that you have seen how to add text to the screen, let us also add a button. When pressed a text should appear as response to the button press.

In this example we declare a TextLabelView and a ButtonView along with a function (buttonClick), to handle the button click event.

The setup function initializes both the text-label and button, sets the label's text alignment and initial empty string value. The function buttonClick is set as the click callback handler on the button.

#include <mono.h>

mono::ui::ButtonView btn;
mono::ui::TextLabelView lbl;

void buttonClick() {
    lbl.setText("Hooray!");
}

void setup() {
    lbl = mono::ui::TextLabelView(mono::geo::Rect(20, 60, 136,40), "");
    lbl.setAlignment(mono::ui::TextLabelView::ALIGN_CENTER);
    lbl.show();

    btn = mono::ui::ButtonView(mono::geo::Rect(20, 100, 136, 40), "Click me");
    btn.setClickCallback(&buttonClick);
    btn.show();
}

void loop() { }

Stop watch

Our last example is a fully functioning stop watch, that counts 10th of milliseconds. We add two buttons to toggle the timer and reset the count value.

Before we get to the example code, let us examine the extra functions in this app. Besides to two familiar setup and loop functions, we have 3 extra functions:

reset: Resets the counter to 00:00.00.
toggle: Starts or stops the counter (toggles a Timer object)
increment: Increments the counter value by 10 ms.

One thing to note is we store the timestamp in two distinct objects. An unsigned integer stores the millisecond component of the counter. Every time it reaches 1000 ms we increment the other timestamp (a DateTime object), that stores the minutes and seconds.

#include <mono.h>

using mono::ui::TextLabelView; // import the classes into the global namespace
using mono::ui::ButtonView;

TextLabelView lbl;
ButtonView resetCntBtn, toggleBtn;
mono::Timer tim;
mono::DateTime count;
uint32_t countMs;

void reset() // Reset the counter, and update display
{
    count = mono::DateTime(0,0,0,0,0,0);
    countMs = 0;
    lbl.setText(mono::String::Format("%02d:%02d.%02d", 
    	count.Minutes(), count.Seconds(), countMs/10));
}

void toggle() // start/stop the timer and update button text
{
    if (tim.Running()) {
        toggleBtn.setText("Start");
        tim.stop();
    } else {
        toggleBtn.setText("Pause");
        tim.start();
    }
}

void increment() // increment the milliseconds, and update timestamp if needed
{
    countMs += 10; // add 10 ms (the timers interval)

    if (countMs >= 1000) { // if more than 1 sec, increment the timestamp object
        countMs = 0;
        count = count.addSeconds(1);
    }

    lbl.setText(mono::String::Format("%02d:%02d.%02d", 
    	count.Minutes(), count.Seconds(), countMs/10));
}

void setup() // add text label, buttons and the timer
{
    lbl = TextLabelView(mono::geo::Rect(50,10,156,70),"00:00.00");
    lbl.show();

    reset(); // set the initial count to zero

    resetCntBtn = ButtonView(mono::geo::Rect(20,160, 136, 40), "Reset Count");
    resetCntBtn.setClickCallback(&reset);
    resetCntBtn.show();

    toggleBtn = ButtonView(mono::geo::Rect(20,100, 136, 40), "Start");
    toggleBtn.setClickCallback(&toggle);
    toggleBtn.show();

    tim.setInterval(10); // set the timer interval to 10 ms
    tim.setCallback(&increment); // the timers callback function
}

void loop() { }

Again, we use the setup function to initialize all our components: TextLabelView, ButtonView and Timer.

This was three quick examples of Mono apps coded in Arduino IDE. We hope you found some inspiration and want to try out our Arduino SDK yourself. As said earlier, a good place to start is at developer.openmono.com.