%\newcommand{\lampon}{\raisebox{4ex}{$1 \kern-1em\raisebox{2ex}{\bclampe}$}}
\newcommand{\lampon}{\raisebox{5.5ex}{$\begin{array}[b]{c}
    \bclampe \\ 
    1
\end{array}$}} % assuming \begin{frame}[fragile]
\scalebox{1}{
\begin{tikzpicture}[shorten >=0.8pt,node distance=2cm,on grid,auto,
    double distance=1.5pt,
    every state/.style={
      semithick,
      fill=gray!10,
      shape=rectangle
    },
    every edge/.style={
      draw,->,
      >={Stealth[length=2.8mm,width=3.6mm,inset=2.3mm]},
      semithick,
      auto
    },
    every loop/.style={looseness=8}]
   \node (s0) {$0000$}; 
   \node[state] (r0) [right=of s0,xshift=-5mm] {$r$};
   \node (a0) [above=of r0,yshift=-5mm] {$1011$,0}; 
   \path [->] (s0) edge node {} (r0);
   \path [->] (a0) edge node {} (r0);

   \node (s1) [right=of r0] {$1011$};
   \path [->] (r0) edge node {} (s1);
   \node[state] (r1) [right=of s1] {$r$};
   \node (a1) [above=of r1,yshift=-5mm] {$0001$,0}; 
   \path [->] (s1) edge node {} (r1);
   \path [->] (a1) edge node {} (r1);

   \node (s2) [right=of r1] {$1100$};  
   \path [->] (r1) edge node {} (s2);
   \node[state] (r2) [right=of s2] {$r$};
   \node (a2) [above=of r2,yshift=-5mm] {$0101$,1}; 
   \path [->] (s2) edge node {} (r2);
   \path [->] (a2) edge node {} (r2);

   \node (s3) [right=of r2] {$0000$};  
   \path [->] (r2) edge node {} (s3);
\end{tikzpicture}
}