String to Bit Transition Task
Given an input string of one or more ASCII characters which codepoints are between 0 and 128 (exclusive), do the following:

Convert each character into its 7-bit ASCII code (if the ASCII code is less than 7 bits, put leading zero bits)
Concatenate all bits (this results in 7*n bits where n is the number of characters)
For each bit in this bitstream, print 1 if it is different from the previous bit, and print 0 otherwise. The first output bit is always 1.

Example
Input:
Hi

Output:
11011001011101

Explanation:

The string &quot;Hi&quot; has the ASCII codes
72 105
which in bits are:
1001000 1101001
And the transition bits indicators:
11011001011101

This is code golf. Lowest byte count wins.
Test Cases
Test case 1:
Hello World!
110110010101110011010101101010110001110000111110000110000001011101101010101100110001

Test case 2:
%% COMMENT %%
1110111111011111100001100010010100001010110101011010011101010011111110011000001101111110111

Test case 3 (credit to Luis Mendo):
##
11100101110010


Congrats to Luis Mendo for the shortest solution with 9 bytes in MATL!
Python 2, 58 bytes



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


Try it online!