Computer to Arduino mega via serial changing values - visual-c++

Question

to start off, this might not be a problem with arduino code or arduino, but I figured I would post here because I really just can not figure out what is wrong.
I am working on this project just for fun to send key strokes from the keyboard, through the computer, and out through the USB to my arduino mega. No additional hardware is here, just the computer, the arduino, and the USB cable.
I am using Microsoft Visual Studio Express 2012 to write code to receive key strokes and send them to the USB. This is the code I am using:
#include "stdafx.h"
#include "conio.h"
using namespace System;
using namespace System::IO::Ports;
int main(array<System::String ^> ^args)
{
String^ portName;
String^ key;
int baudRate=9600;
Console::WriteLine("type in a port name and hit ENTER");
portName=Console::ReadLine();
//arduino settings
SerialPort^ arduino;
arduino = gcnew SerialPort(portName, baudRate);
//open port
try
{
arduino->Open();
while(1)
{
int k = getch();
key = k.ToString();
Console::WriteLine(key);
arduino->Write(key);
if (k == 32)
return 0;
}
}
catch (IO::IOException^ e )
{
Console::WriteLine(e->GetType()->Name+": Port is not ready");
}
}
This code works fine, and sends commands to the arduino. I might as well ask this as well, but after 35 key strokes it just stops sending key strokes, I am unsure as to why, but that is not an arduino problem (I don't think).
So when the certain value for key gets sent to the arduino, it changes. For example, the values that are assigned to the variable key for pressing the number 1 and 2 are 49 and 50, respectively. However, when they get sent to the arduino, the values are different some how. 1 is now 57, and 2 is now 48. I am unsure as to why this is happening. I tried 4 and 5 and they both have their values shift down 2 like the key 2. This is the code I have on the arduino:
int ledPin = 13;
int key=0;
int c;
void setup()
{
pinMode(ledPin, OUTPUT); // pin will be used to for output
Serial.begin(9600); // same as in your c++ script
}
void loop()
{
if (Serial.available() > 0)
{
key = Serial.read(); // used to read incoming data
if (key == 57)
{
digitalWrite(ledPin, HIGH);
}
else if (key == 48)
{
digitalWrite(ledPin, LOW);
}
}
c = key;
Serial.println(c);
}
As of right now it is just to switch a light on and off. I am hoping to involve many more keys and having the values be consistent would be very convenient. Anyways, if anyone could help me with why the values are different that would be awesome. I am not completely new to programming but I am certainly no expert and have not gotten too far into advanced stuff.
Thank you for any help or advice.

Answer 1

This has to do with what you are sending through visual studio. You are converting a keypress to its ASCII value, then converting that ASCII value to string, then sending that string through serial. The arduino is expecting a number, not a string.
For example, if you press the 1 key, your visual studio code converts that to an ASCII number 49, which is then converted to string "49", which the Arduino receives - but since you are sending "49", which is a "4" and an "9", the Arduino is reading 9 which corresponds to 57, as you have seen.
Similarly, pressing 2 converts it to "50", and the Arduino reads "0" which corresponds to the value 48 which you were getting.
To fix this, send the number directly, don't convert it into a string.