C++ Gadget Library for Linux

This library is built on top of the gpio++ library. It abstracts various gadgets that can be controlled/emulated via GPIO pins.

Currently implemented gadgets are:

• gadget::contact - push button, switch, etc.
• gadget::encoder - rotary encoder
• gadget::led - single color LED
• gadget::rgb_led - RGB LED

Getting Started

Prerequisites

• asio C++ Library >= 1.10.10
• C++ GPIO Library for Linux >= 4.0
• CMake >= 3.1

Installation

Binary (Debian/Ubuntu/etc):

$ version=2.0
$ arch=$(uname -p)
$ wget https://github.com/dimitry-ishenko-cpp/gadget/releases/download/v${version}/gadget++_${version}_Linux_${arch}.deb
$ sudo apt install ./gadget++_${version}_Linux_${arch}.deb

Compile from source:

$ version=2.0
$ wget https://github.com/dimitry-ishenko-cpp/gadget/releases/download/v${version}/gadget++-${version}-Source.tar.bz2
$ tar xjf gadget++-${version}-Source.tar.bz2
$ mkdir gadget++-${version}-Source/build
$ cd gadget++-${version}-Source/build
$ cmake .. -DCMAKE_INSTALL_PREFIX=/usr
$ make
$ sudo make install

Clone and compile from repository:

$ git clone https://github.com/dimitry-ishenko-cpp/gadget.git gadget++
$ mkdir gadget++/build
$ cd gadget++/build
$ cmake .. -DCMAKE_INSTALL_PREFIX=/usr
$ make
$ sudo make install

Usage

Example:

#include <gadget++/contact.hpp>
#include <gadget++/encoder.hpp>
#include <gadget++/rgb_led.hpp>
#include <gadget++/temp.hpp>
#include <gpio++.hpp>

#include <asio.hpp>

#include <algorithm>
#include <iostream>

using namespace gpio::literals;
using namespace gadget::literals;

using std::cout; using std::endl;

int main()
{
    asio::io_service io;
    auto chip = gpio::get_chip(io);

    // optical encoder
    gadget::encoder encoder(chip->pin(5), chip->pin(6), pull_up);

    // push button
    gadget::contact button(io, chip->pin(7), pull_up);

    // rgb led
    gadget::rgb_led led(chip->pin(14), chip->pin(15), chip->pin(16));

    // initial color temp and level
    gadget::temp temp = 3200_K;
    led.color(gadget::to_color(temp));
    led.dim(10_pc);

    // control mode
    enum { set_temp, set_level } mode = set_level;

    // switch between color temp and level
    button.on_tap([&]()
    {
        switch(mode)
        {
        case set_temp:
            cout << "Switching to level mode" << endl;
            mode = set_level;
            break;

        case set_level:
            cout << "Switching to color temp mode" << endl;
            mode = set_temp;
            break;
        }
    });

    // adjust color temp or level
    encoder.on_rotate([&](gadget::encoder_step step)
    {
        switch(mode)
        {
        case set_temp:
            // adjust color temp
            temp = temp + step * 100_K;

            // clamp color temp between 400K and 40,000K
            temp = std::max(std::min(temp, 40000_K), 400_K);

            led.color(gadget::to_color(temp));
            cout << "Setting color temp to " << temp << "K" << endl;
            break;

        case set_level:
            // adjust level
            led.dim(led.level() + step * 2_pc);
            cout << "Setting level to " << led.level() << "%" << endl;
            break;
        }
    });

    asio::system_timer timer(io);
    std::function<void()> dim_led = [&]()
    {
        led.dim(led.level() - 2_pc);

        if(led.level() > 0_pc)
        {
            timer.expires_from_now(100ms);
            timer.async_wait([&](const asio::error_code& ec) { if(!ec) dim_led(); });
        }
    };
    button.on_tap_twice(dim_led);

    io.run();
    return 0;
}

Compile and run:

$ g++ example.cpp -o example -DASIO_STANDALONE -lgadget++ -lgpio++-pigpio -lpigpio
$ ./example

Authors

• Dimitry Ishenko - dimitry (dot) ishenko (at) (gee) mail (dot) com

License

This project is distributed under the GNU GPL license. See the LICENSE.md file for details.