Source code for the Electric Imp GraphButton example.

gistfile1.c

// GraphButton source code

// Set output port for planner.
local output = OutputPort("trigger");
 
// Callback when the button is pressed.
function pin7changed() {
    local buttonState = hardware.pin7.read();
 
    // If buttonState is 0, the button is pushed.
    if (buttonState == 0) {
        hardware.pin8.write(0);
        output.set("trigger");
        server.show("Button Pressed!");
    } else {
        hardware.pin8.write(1);
        server.show("Button Released!");
    }
}

// LEDs on pin 8 is active low, so writing the pin a 1 will turn the LED off.
hardware.pin8.configure(DIGITAL_OUT_OD_PULLUP);
hardware.pin8.write(1);
server.show("LEDs configured.");
 
// Pin 7 is a digital input (0 or 1) and is pulled up externally.
hardware.pin7.configure(DIGITAL_IN_PULLUP, pin7changed);

// Register with the server
imp.configure("GraphButton POSTer", [], [output]);

// Display our important message
server.show("GraphButton ready.");