Question

which function convert an integer to an unicode character in python

Answer 1

Just use chr(somenumber) to get a 1 byte value of an int as long as it is less than 256. pySerial will then send it fine.

If you are looking at sending things over pySerial it is a very good idea to look at the struct module in the standard library it handles endian issues an packing issues as well as encoding for just about every data type that you are likely to need that is 1 byte or over.

Answer 2

 unichrx function will convert an integer to a Unicode character.