BOARDS/CARDPUTER CircuitPython/keyboard.py

import sys

class Keyboard:
    def __init__(self):
        # the number row starts with 3 and ends with the number, e.g. key number 5 is 0x35
        self.number_row=["0x30","0x31","0x32","0x33","0x34","0x35","0x36","0x37","0x38","0x39"]
        self.chars={
            "0x21":"!","0x40":"@","0x23":"#","0x24":"$","0x25":"%","0x5e":"^","0x26":"&","0x2a":"*","0x28":"(","0x29":")", "0x3f":"?",
            "0x27":"'", "0x22":"\"", "0x3a":":", "0x3c":"<", "0x3e":">"
        }
        self.lowercase={
            "0x71":"q", "0x77":"w", "0x65":"e", "0x72":"r", "0x74":"t", "0x79":"y", "0x75":"u", "0x69":"i", "0x6f":"o", "0x70":"p",
            "0x61":"a", "0x73":"s", "0x64":"d", "0x66":"f", "0x67":"g", "0x68":"h", "0x6a":"j", "0x6b":"k", "0x6c":"l",
            "0x7a":"z", "0x78":"x", "0x63":"c", "0x76":"v", "0x62":"b", "0x6e":"n", "0x6d":"m"
        }
        self.uppercase={
            "0x51":"Q", "0x57":"W", "0x45":"E", "0x52":"R", "0x54":"T", "0x59":"Y", "0x55":"U", "0x49":"I", "0x4f":"O", "0x50":"P",
            "0x41":"A", "0x53":"S", "0x44":"D", "0x46":"F", "0x47":"G", "0x48":"H", "0x4a":"J", "0x4b":"K", "0x4c":"L",
            "0x5a":"Z", "0x58":"X", "0x43":"C", "0x56":"V", "0x42":"B", "0x4e":"N", "0x4d":"M"
        }
        self.special={
            "0xa":"\n", "0x8":"BACKSP", "0x20":" ", "0x3b":"UP", "0x2e":"DOWN", "0x2c":"LEFT", "0x2f":"RIGHT", "0x10d":"OPTD",
            "0x4":"CTRLD", "0x13":"CTRLS", "0x9":"    ", "0x60":"ESC", "0xf":"CTRLO"
        }

    def scan(self):
        code=hex(ord(sys.stdin.read(1)))
        #printing the code can be useful for debugging purposes, to check that the codes have been logged correctly if something unexpected is happening
        #print(code)
        key = None
        if code in self.number_row:
            key = str(self.number_row.index(code))
        elif code in self.chars:
            key = self.chars[code]
        elif code in self.lowercase:
            key = self.lowercase[code]
        elif code in self.uppercase:
            key = self.uppercase[code]
        elif code in self.special:
            key = self.special[code]
            
        if key:
            return key
        else:
            return "UNKNOWN "+code

    def is_alphanumeric(self, key):
        if key in self.special.values() or key in self.chars.values():
            return False
        else:
            return True