I have been playing with this the last couple days and finally got it to work. The title pretty much says it all. I have an Arduino with an Ethernet shield that receives requests from PowerShell that is querying the computer for RAM and CPU usage. I am really new to Arduino, but I figured this might help somebody. I have to give credit to hari http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1284844153. He posted some web server code that I modified to make my project work.
I literally just got it working so it may be a little rough. Take it easy 
Here is the Arduino code:
/*
Arduino Data Web Server
Performs actions on Arduino and/or returns data from Arduino to a webbrowser request URL:
- To turn on LED on pin 8, use web browser to visit your Arduino via: http://x.x.x.x/digitalWrite/7/1
- To turn it off send: http://x.x.x.x/digitalWrite/7/0
- To read analog0 value, send: http://x.x.x.x/analogRead/0
IMPORTANT:
Commands are case sensitive, but I wrote this as simple as possible so it can be easily adapted to your needs.
Have fun!
created Sept 17, 2010
by Hari Wiguna, g33k.blogspot.com
*/
/*
I have modified the original Arduino Data Web Server code by Hari. Please see his site above for the original.
*/
// include the library code:
#include <LiquidCrystal.h>
#include <SPI.h>
#include <Ethernet.h>
#include <string.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(2, 3, 4, 5, 6, 7);
byte mac[] = {0x90, 0xA2, 0xDA, 0x00, 0x33, 0x3A };
byte ip[] = {192.168.1.1}; // IP Address of arduino
Server server(80); // Port 80 is http.
//Command Parameters
char cmd[15];
char param1[15];
char param2[15];
#define bufferMax 128
int bufferSize;
char buffer[bufferMax];
void setup() {
//Ethernet
Ethernet.begin(mac, ip);
server.begin();
Serial.begin(9600);
Serial.println("Starting serial debugging at 9600");
lcd.setCursor(0,0);
lcd.begin(16, 2);
}
void loop() {
Client client = server.available();
if (client)
{
WaitForRequest(client);
ParseReceivedRequest();
PerformRequestedCommands();
client.stop();
}
}
void WaitForRequest(Client client) // Sets buffer[] and bufferSize
{
bufferSize = 0;
while (client.connected()) {
if (client.available()) {
char c = client.read();
if (c == '\n')
break;
else
if (bufferSize < bufferMax)
buffer[bufferSize++] = c;
else
break;
}
}
PrintNumber("bufferSize", bufferSize);
}
void ParseReceivedRequest()
{
Serial.println("in ParseReceivedRequest");
Serial.println(buffer);
//Received buffer contains "GET /cmd/param1/param2 HTTP/1.1". Break it up.
char* slash1;
char* slash2;
char* slash3;
char* space2;
slash1 = strstr(buffer, "/") + 1; // Look for first slash
slash2 = strstr(slash1, "/") + 1; // second slash
slash3 = strstr(slash2, "/") + 1; // third slash
space2 = strstr(slash2, " ") + 1; // space after second slash (in case there is no third slash)
if (slash3 > space2) slash3=slash2;
PrintString("slash1",slash1);
PrintString("slash2",slash2);
PrintString("slash3",slash3);
PrintString("space2",space2);
// strncpy does not automatically add terminating zero, but strncat does! So start with blank string and concatenate.
cmd[0] = 0;
param1[0] = 0;
param2[0] = 0;
strncat(cmd, slash1, slash2-slash1-1);
strncat(param1, slash2, slash3-slash2-1);
strncat(param2, slash3, space2-slash3-1);
PrintString("cmd",cmd);
PrintString("param1",param1);
PrintString("param2",param2);
}
void PerformRequestedCommands()
{
if ( strcmp(cmd,"CPU") == 0 ) PrintCPU(); //This used to be a digitalwrite and digitalread
if ( strcmp(cmd,"RAM") == 0 ) PrintRAM();
}
void PrintCPU()
{
int stars = param1[0] - '0';
PrintNumber("stars",stars);
lcd.setCursor(0,0);
lcd.print("CPU:[");
lcd.setCursor(5, 0); //CPU
if(stars == 0)
{
lcd.print("**********");
}
else
{
for(int x=0;x<stars;x++)
{
lcd.print("*");
}
for(int x=stars;x<11;x++)
{
lcd.print(" ");
}
}
lcd.setCursor(15,0);
lcd.print("]"); //closing bracket
Serial.println("CPU Data recieved.");
server.print("CPU data recieved.");
}
void PrintRAM()
{
int stars = param1[0] - '0';
PrintNumber("stars",stars);
lcd.setCursor(0,1);
lcd.print("RAM:[");
lcd.setCursor(5, 1); //RAM
if(stars == 0)
{
lcd.print("**********");
}
else
{
for(int x=0;x<stars;x++)
{
lcd.print("*");
}
for(int x=stars;x<11;x++)
{
lcd.print(" ");
}
}
lcd.setCursor(15,1);
lcd.print("]"); //closing bracket
Serial.println("RAM Data recieved.");
server.print("RAM data recieved.");
}
void PrintString(char* label, char* str)
{
Serial.print(label);
Serial.print("=");
Serial.println(str);
}
void PrintNumber(char* label, int number)
{
Serial.print(label);
Serial.print("=");
Serial.println(number, DEC);
}
Here is the PowerShell code:
#This gets the performance of local computer and sends it to arduino board
While($x -ne 0)
{
Get-Performance
Start-Sleep -s 10 #this will run the powershell script every 10 seconds.
}
Function Get-Performance(){
$CPU = Get-WmiObject win32_processor | Measure-Object -property LoadPercentage -Average | Select Average
$SystemInfo = Get-WmiObject -Class Win32_OperatingSystem | Select-Object Name, TotalVisibleMemorySize, FreePhysicalMemory
$perRam = (($SystemInfo.FreePhysicalMemory/1MB) / ($systeminfo.totalvisiblememorysize/1MB)) * 100
$perRam = 100 - $perRam
Write-host ("CPU: " + $CPU.Average + "%")
Write-host ("Ram: " + $perRam + "%")
$CPUStars = $CPU.Average / 10
$RAMStars = $perRam /10
if($CPUStars -lt 1){$CPUStars = 1}
Write-host ("{0:N0}" -f $CPUStars)
Write-host ("{0:N0}" -f $RAMStars)
$evalCPUStars = "{0:N0}" -f $CPUStars
$evalRAMStars = "{0:N0}" -f $RAMStars
$server = "<put your IP of the arduino here>"
#this will get our page for later
$cpuPage = (New-Object System.Net.WebClient).DownloadString("http://" + $server + "/CPU/" + $evalCPUStars)
$ramPage = (New-Object System.Net.WebClient).DownloadString("http://" + $server + "/RAM/" + $evalRAMStars)
Write-host("http://" + $server + "/CPU/" + $evalCPUStars)
Write-host("http://" + $server + "/RAM/" + $evalRAMStars)
}
Hope this helps someone. Feel free to do whatever you want with it. 
