#
# PRTG Custom Sensor to read EAC-USB-Stick with 2xS0 and 1Wire-Device
#
# 20140520 Ver 1.0  Initial Version
# 20140526 Ver 1.1  units and Normalization für S0 and temperature added
# 20140530 Ver 1.2  Fix: S0 Counter was absolute and not "Difference"

param (
   [string]$comport = "COM4",
   [long]$bitrate = "9600",  # default baud rate
   [long]$S0Afactor= 1000,  #  used to divide the 
   [long]$S0Bfactor= 1000   # 
)

[hashtable]$1wirename = @{
	"1016EEAC020800E8"="SensorRack1";
	"1016EEAC020800E9"="SensorRack2"
}

$1wirelist=@{}
[string]$prtgresult=""
$prtgresult+="<?xml version=""1.0"" encoding=""Windows-1252"" ?>`r`n"
$prtgresult+="<prtg>`r`n"

$port= new-Object System.IO.Ports.SerialPort $comport,$bitrate,None,8,one
$port.ReadTimeout=5000
$port.WriteTimeout=5000
$port.open()

$port.WriteLine('$?')
write-host "Scanning 1-Wire on Port $comport"
start-sleep -milliseconds 1000
while ($port.BytesToRead -ne 0) {
	$line = $port.ReadLine()
	if ($line.startswith('$S0')) {
		Write-host "Found S0-Line $line"
		$s0array = $line -split(';')
		write-host "  S0-Counter1 = " $s0array[1]
		write-host "  S0-Counter2 = " $s0array[2]
		$prtgresult+="    <result>`r`n"
		$prtgresult+="        <channel>S0-A</channel>`r`n"
		$prtgresult+="        <value>"+(([long]$s0array[1])/$S0Afactor)+"</value>`r`n"
		$prtgresult+="        <float>1</float>`r`n"
		$prtgresult+="        <mode>Difference</mode>"
		$prtgresult+="    </result>`r`n"
		$prtgresult+="    <result>`r`n"
		$prtgresult+="        <channel>S0-B</channel>`r`n"
		$prtgresult+="        <value>"+(([long]$s0array[2])/$S0Bfactor)+"</value>`r`n"
		$prtgresult+="        <float>1</float>`r`n"
		$prtgresult+="        <mode>Difference</mode>"
		$prtgresult+="    </result>`r`n"
	}
	else {
		Write-host "Found 1Wire-Device: $line"
		$1wirearray = $line -split(';')
		$1wirelist.add($1wirearray[0],$1wirearray[2])
	}
}

if ($1wirelist.count -ne 0) {
	foreach ($key in $1wirelist.keys) {
		$port.WriteLine($key)
		start-sleep -milliseconds 100
		$1wiredata = $port.ReadLine()
		write-host ("  1wireData: Device:" + $1wirelist.item($key))
		write-host ("  1wireData:   Data:" + $1wiredata)
		$1wiredataarray = $1wiredata.split(";")
		if ( ($1wirelist.item($key)).startswith("10") ) {
			$highbyte = [Convert]::ToInt32($1wiredataarray[3],16)
			$lowbyte = [Convert]::ToInt32($1wiredataarray[2],16)
			if ($HighByte -eq 00) {
			   $Temperature = $LowByte * 0.5
			}
			else {
			   $Temperature = (256- $LowByte) * - 0.5
			}
			$Temperature = [math]::round($Temperature*10)/10   # reduce the 1/10th digit to one
			write-host "Temperatur $Temperature"
			$prtgresult+="    <result>`r`n"
			if ($1wirename.containskey($1wirelist.item($key))) {
				$prtgresult+=("        <channel>"+$1wirename.item($1wirelist.item($key))+"</channel>`r`n")
			}
			else {
				$prtgresult+=("        <channel>"+$1wirelist.item($key)+"</channel>`r`n")
			}
			$prtgresult+="        <value>"+$Temperature+"</value>`r`n"
			$prtgresult+="        <float>1</float>`r`n"
			#$prtgresult+="        <customunit>Grad C</customunit>`r`n"
			#$prtgresult+="        <mode>Absolute</mode>`r`n"
			$prtgresult+="    </result>`r`n"
		}
	}
}
$prtgresult+="</prtg>"
write-host "Sending PRTGRESuLT to STDOuT"
$prtgresult
$port.Close()