import machine
import time

class Vector4Keyboard:
    def __init__(self, pin):
        self.pin = pin
        pin.value(True)

    def type(self, char):
        c = ord(char)
        self._bit(False)
        for bit in range(7):
            self._bit(c&1)
            c >>= 1
        self._bit(False)
        self.pin.value(True)
        time.sleep_ms(71)

    def _bit(self, bit):
        self.pin.value(bit)
        time.sleep_us(3400)


kbd = Vector4Keyboard(machine.Pin(17, machine.Pin.OUT))
for c in "hello world": kbd.type(c)