Add initial Pen Plotter documentation with a TODO note

Author: 0xfab1

docs/tech/hardware/maker-tools/pen-plotter.md

@@ -0,0 +1,3 @@
+# Pen Plotter
+
+TODO

docs/tech/scripts/powershell/snippets.md

@@ -16,3 +16,168 @@ One-liner to convert all PNG Images of a folder to JPG images:
 ``` ps1
 Get-ChildItem -Path (Get-Location) -Filter *.png | ForEach-Object { $img=[System.Drawing.Image]::FromFile($_.FullName); $jpg=([System.IO.Path]::ChangeExtension($_.FullName, '.jpg')); $enc=[System.Drawing.Imaging.ImageCodecInfo]::GetImageEncoders()|?{$_.MimeType -eq 'image/jpeg'}; $par=New-Object System.Drawing.Imaging.EncoderParameters(1); $par.Param[0]=New-Object System.Drawing.Imaging.EncoderParameter([System.Drawing.Imaging.Encoder]::Quality,90); $img.Save($jpg,$enc,$par); $img.Dispose() }; Write-Output 'Conversion complete.'
 ```
+
+## Netzwerk
+
+### UDP
+
+#### UDP Sender
+
+``` ps1
+$udpSender = New-Object System.Net.Sockets.UdpClient
+$bytes = [System.Text.Encoding]::UTF8.GetBytes("Hallo vom Client")
+$udpSender.Send($bytes, $bytes.Length, "1.2.3.5", 12345)
+$udpSender.Close()
+```
+
+#### UDP Listener
+
+``` ps1
+$udpClient = New-Object System.Net.Sockets.UdpClient 12345
+$remoteEP = New-Object System.Net.IPEndPoint ([System.Net.IPAddress]::Any, 0)
+
+Write-Host "Lausche auf UDP-Port 12345..."
+
+while ($true) {
+    $data = $udpClient.Receive([ref]$remoteEP)
+    $text = [System.Text.Encoding]::UTF8.GetString($data)
+    Write-Host "Empfangen von $($remoteEP.Address): $text"
+}
+```
+
+#### UDP Check
+
+``` ps1
+Get-NetUDPEndpoint | Select-Object -Property LocalAddress, LocalPort, OwningProcess | Sort-Object LocalPort
+```
+
+### With iPerf
+
+UDP Download
+
+``` ps1
+iperf3.exe -c <server> -u -P 10 -4 -R
+```
+
+UDP Upload
+
+``` ps1
+iperf3.exe -c <server> -u -P 10 -4
+```
+
+### TCP
+
+#### TCP Connect
+
+``` ps1
+try { (New-Object Net.Sockets.TcpClient).Connect("1.2.3.4", 7600); "offen" } catch { "zu" }
+```
+
+#### TCP Firewall check
+
+``` ps1
+$tcp = New-Object System.Net.Sockets.TcpClient
+$tcp.ReceiveTimeout = 3000
+$tcp.SendTimeout = 3000
+$sw = [System.Diagnostics.Stopwatch]::StartNew()
+try {
+    $tcp.Connect("1.2.3.4", 7600)
+    "Port offen"
+} catch {
+    $sw.Stop()
+    if ($sw.ElapsedMilliseconds -ge 2500) {
+        "Möglicherweise gefiltert (Timeout)"
+    } else {
+        "Port wahrscheinlich geschlossen (RST empfangen)"
+    }
+}
+```
+
+#### TCP Listener
+
+``` ps1
+$listener = [System.Net.Sockets.TcpListener]::Create(7600)
+$listener.Start()
+Write-Host "TCP-Listener läuft auf Port 7600..."
+
+while ($true) {
+    if ($listener.Pending()) {
+        $client = $listener.AcceptTcpClient()
+        Write-Host "Neue Verbindung: $($client.Client.RemoteEndPoint)"
+        $client.Close()
+    }
+    Start-Sleep -Milliseconds 500
+}
+```
+
+#### TCP Check
+
+``` ps1
+Get-NetTCPConnection -State Listen | Select-Object -Property LocalAddress, LocalPort, OwningProcess | Sort-Object LocalPort
+```
+
+#### TCP Check with iPerf
+
+TCP Download
+
+``` ps1
+iperf3.exe -c <server> -P 10 -4 -R
+```
+
+TCP Upload
+
+``` ps1
+iperf3.exe -c <server> -P 10 -4
+```
+
+### Multicast
+
+Checks
+
+- Port must be allowed (check Firewall local or in network)
+- Verify that the network infrastructure (switches, routers) allows multicast (no filtering/IGMP blocking).
+- Ensure both sender and receiver are on the same LAN/subnet (unless you have multicast routing set up).
+- Use a multicast address in the range 224.0.0.0 to 239.255.255.255
+
+#### Listener
+
+``` ps1
+$groupAddress = "239.255.0.1"
+$port = 5001
+
+$udpClient = New-Object System.Net.Sockets.UdpClient
+$localEp = New-Object System.Net.IPEndPoint ([System.Net.IPAddress]::Any, $port)
+$udpClient.Client.SetSocketOption([System.Net.Sockets.SocketOptionLevel]::Socket, [System.Net.Sockets.SocketOptionName]::ReuseAddress, $true)
+$udpClient.ExclusiveAddressUse = $false
+$udpClient.Client.Bind($localEp)
+
+$udpClient.JoinMulticastGroup([System.Net.IPAddress]::Parse($groupAddress))
+
+Write-Host "Listening for multicast on $groupAddress:$port..."
+while ($true) {
+    $received = $udpClient.Receive([ref]$localEp)
+    $text = [System.Text.Encoding]::UTF8.GetString($received)
+    Write-Host "Received from $($localEp.Address): $text"
+}
+```
+
+### Sender
+
+``` ps1
+$groupAddress = "239.255.0.1"
+$port = 5001
+$message = "Hello multicast from $(hostname)"
+$remoteIp = [System.Net.IPAddress]::Parse($groupAddress)
+$remoteEp = New-Object System.Net.IPEndPoint $remoteIp, $port
+
+$udpClient = New-Object System.Net.Sockets.UdpClient
+$bytes = [System.Text.Encoding]::UTF8.GetBytes($message)
+
+for ($i = 1; $i -le 10; $i++) {
+    $udpClient.Send($bytes, $bytes.Length, $remoteEp) | Out-Null
+    Write-Host "Sent: $message"
+    Start-Sleep -Seconds 1
+}
+
+$udpClient.Close()
+```