How to send a number as a byte?
The problem is the BIN in your print statement.  Everything is ALWAYS binary.  The BIN means to break that binary up into ascii digits 0 and 1.  So if you send
Serial.print(21, BIN);
then the print function takes 21 as a binary number, 00010101 and then sends those binary digits as ascii.  So what goes out on the wire is 8 separate bytes, it goes 48, 48, 48, 49, 48, 49, 48, 49 as 48 and 49 are the ascii codes for 0 and 1.
What you want to do is just to send the raw byte.  So use Serial.write instead.  The print functions convert things to ascii representations but the write function just sends the raw bytes out.  So if you write:
Serial.write(inches);

Assuming that inches is a byte type variable then it just sends the raw byte out.