String to Bit Transition

Python 2, 58 bytes

n=1
for c in input():n=n<<7|ord(c)
print'1'+bin(n^n/2)[4:]

Try it online!

MATL, 9 bytes

Hj7&B!hdg

Try it online!

Explanation

H     % Push 2
j     % Read line of input, unevaluated
7&B   % Convert to binary with 7 bits. Gives a 7-column matrix
!     % Transpose
h     % Concatenate horiontally. The matrix is read in column-major order
d     % Consecutive differences
g     % Convert to logical. Implicitly display

Japt -P, 11 bytes

Takes advantage of the fact that spaces can be coerced to 0 in JavaScript when trying to perform a mathematical or, in this case, bitwise operation on it.

c_¤ù7Ãä^ i1

Try it or run all test cases

c_¤ù7Ãä^ i1     :Implicit input of string
c_              :Map codepoints
  ¤             :  Convert to binary string
   ù7           :  Left pad with spaces to length 7
     Ã          :End map
      ä^        :XOR consecutive pairs
         i1     :Prepend 1
                :Implicitly join and output