Arduino replaces MT-VIKI KVM remote module for changing / polling selected KVM input

mt_viki_remote

#include <math.h>

// connected to 'D+' pin on mini USB
const int input_pin = 11;
// connected to 'D-' pin on mini USB
const int output_pin = 12;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(input_pin, INPUT);
  pinMode(output_pin, OUTPUT);
  digitalWrite(output_pin, HIGH);
}

void loop() {
  if (Serial.available() > 0) {
    int new_port = Serial.parseInt();
    if (new_port >= 1 && new_port <=8) {
      set_port(new_port);
    }
    int port = get_port();
    Serial.println(port);
  }
}

int get_port() {
  unsigned long duration;
  double ms;
  int p;
  duration = pulseIn(input_pin, LOW);
  ms = round(duration / 1000.0);
  p = ((int) ms / 20);
  return (p);
}

void set_port(int p) {
      digitalWrite(output_pin, LOW);
      delay(20);
      digitalWrite(output_pin, HIGH);
      delay(20);
      digitalWrite(output_pin, LOW);
      delay(p * 20);
      digitalWrite(output_pin, HIGH);
      delay(200);
}

In case anyone wants to do this with the GPIO pins on a Raspberry Pi instead, here's the equivalent Python code.

import RPi.GPIO as GPIO
import sys
import time

input_pin = 23  # connected to 'D+' pin on mini USB
output_pin = 24  # connected to 'D-' pin on mini USB


def setup():
    GPIO.setmode(GPIO.BCM)
    GPIO.setwarnings(False)
    GPIO.setup(input_pin, GPIO.IN)
    GPIO.setup(output_pin, GPIO.OUT)
    GPIO.output(output_pin, GPIO.HIGH)


def get_port() -> int:
    while GPIO.input(input_pin) == GPIO.LOW:
        time.sleep(0.001)
    while GPIO.input(input_pin) == GPIO.HIGH:
        time.sleep(0.001)
    start = time.time()
    while GPIO.input(input_pin) == GPIO.LOW:
        time.sleep(0.001)
    stop = time.time()
    return round((stop - start) * 50)


def set_port(port: int):
    GPIO.output(output_pin, GPIO.LOW)
    time.sleep(0.02)
    GPIO.output(output_pin, GPIO.HIGH)
    time.sleep(0.02)
    GPIO.output(output_pin, GPIO.LOW)
    time.sleep(0.02 * port)
    GPIO.output(output_pin, GPIO.HIGH)


setup()
set_port(int(sys.argv[1]))