This feels like it should be very simple, but I haven't been able to find an answer..
In a python script I am reading in data from a USB device (x and y movements of a USB mouse). it arrives in single ASCII characters. I can easily convert to unsigned integers (0-255) using ord. But, I would like it as signed integers (-128 to 127) - how can I do this?
Any help greatly appreciated! Thanks a lot.
Subtract 256 if over 127:
unsigned = ord(character)
signed = unsigned - 256 if unsigned > 127 else unsigned
Alternatively, repack the byte with the struct
module:
from struct import pack, unpack
signed = unpack('B', pack('b', unsigned))[0]
or directly from the character:
signed = unpack('B', character)[0]