Examples of Esterel programs

These programs were written by two students from the École Centrale de Nantes. 
  Follow a border with one light sensor


module example1 : 
input LIGHT_LOW_1; 
output MOTOR_A_SPEED(integer),MOTOR_C_SPEED(integer), MOTOR_A_DIR(integer), MOTOR_C_DIR(integer); 
output SET_LIGHT_1_THRESHHOLD : integer;

constant MOTOR_FWD, MOTOR_REV : integer; 
constant TICKS_PER_SECOND = 1000 : integer; 

emit SET_LIGHT_1_THRESHHOLD(80);
loop 
   emit MOTOR_A_DIR(MOTOR_REV); 
   emit MOTOR_C_DIR(MOTOR_FWD);
   emit MOTOR_A_SPEED(20); 
   emit MOTOR_C_SPEED(100);
   await LIGHT_LOW_1;
   emit MOTOR_A_DIR(MOTOR_FWD); 
   emit MOTOR_C_DIR(MOTOR_REV);
   emit MOTOR_A_SPEED(100); 
   emit MOTOR_C_SPEED(20); 
end loop.
 
 
  Follow a line with one light sensor


module example2 : 
      input LIGHT_LOW_1,LIGHT_HIGH_1; 
      output MOTOR_A_SPEED(integer),MOTOR_C_SPEED(integer), MOTOR_A_DIR(integer),MOTOR_C_DIR(integer); 
      output SET_LIGHT_1_THRESHHOLD : integer;

      constant MOTOR_FWD, MOTOR_REV : integer; 
      constant TICKS_PER_SECOND = 1000 : integer; 

emit SET_LIGHT_1_THRESHHOLD(80);
emit MOTOR_A_DIR(MOTOR_FWD);
emit MOTOR_C_DIR(MOTOR_FWD);
loop
   emit MOTOR_A_SPEED(20);
   emit MOTOR_C_SPEED(100);
   await LIGHT_LOW_1;
   await LIGHT_HIGH_1;
   emit MOTOR_A_SPEED(100);
   emit MOTOR_C_SPEED(20);
   await LIGHT_LOW_1;
   await LIGHT_HIGH_1;
end loop.
 
 
  Follow a border with two light sensors


module example3 : 
input LIGHT_LOW_1,LIGHT_HIGH_1; 
input LIGHT_LOW_2,LIGHT_HIGH_2; 

output MOTOR_A_SPEED(integer),MOTOR_C_SPEED(integer),
        MOTOR_A_DIR(integer),MOTOR_C_DIR(integer); 
output SET_LIGHT_1_THRESHHOLD : integer;
output SET_LIGHT_2_THRESHHOLD : integer;

constant MOTOR_FWD, MOTOR_REV : integer; 
constant TICKS_PER_SECOND = 1000 : integer; 

emit SET_LIGHT_1_THRESHHOLD(80);
emit SET_LIGHT_2_THRESHHOLD(80);
[ 
   loop 
      emit MOTOR_A_DIR(MOTOR_FWD);
      emit MOTOR_A_SPEED(100);
      await LIGHT_LOW_1;
      emit MOTOR_A_DIR(MOTOR_REV);
      emit MOTOR_A_SPEED(20);
      await LIGHT_HIGH_1;
   end loop
||
   loop 
      emit MOTOR_C_DIR(MOTOR_FWD);
      emit MOTOR_C_SPEED(100);
      await LIGHT_HIGH_2;
      emit MOTOR_C_DIR(MOTOR_REV);
      emit MOTOR_C_SPEED(20);
      await LIGHT_LOW_2;
   end loop
].
 
 
  Follow a line with two light sensors


module example4 : 
input LIGHT_LOW_1,LIGHT_HIGH_1; 
input LIGHT_LOW_2,LIGHT_HIGH_2; 

output MOTOR_A_SPEED(integer),MOTOR_C_SPEED(integer),
       MOTOR_A_DIR(integer),MOTOR_C_DIR(integer); 
output SET_LIGHT_1_THRESHHOLD : integer;
output SET_LIGHT_2_THRESHHOLD : integer;

constant MOTOR_FWD, MOTOR_REV : integer; 
constant TICKS_PER_SECOND = 1000 : integer; 

emit SET_LIGHT_1_THRESHHOLD(80);
emit SET_LIGHT_2_THRESHHOLD(80);
emit MOTOR_A_DIR(MOTOR_FWD);
emit MOTOR_C_DIR(MOTOR_FWD); 
[
   loop 
      emit MOTOR_A_SPEED(100);
      await LIGHT_LOW_1;
      emit MOTOR_A_SPEED(20);
      await LIGHT_HIGH_1;
    end loop
||
   loop 
      emit MOTOR_C_SPEED(100);
      await LIGHT_LOW_2;
      emit MOTOR_C_SPEED(20);
      await LIGHT_HIGH_2;
   end loop
].
 

Martin.Richard@emn.fr