typedef uint32_t clock_t;
const clock_t INFINITE = ( (clock_t)(-1) );
const clock_t SEC = 1000;

//
// waiter: returns true and resets if more than time has passed
//
class waiter {
    clock_t last;
public:
    waiter() : last(millis()) {}
    bool wait( const clock_t time ) {
        clock_t now = millis();
        if( now - last >= time ) {
            last = now;
            return true;
        }
        return false;
    };
};