The UDP Data Plotter draws numbers out of UDP datagrams sent to iperfect.net:49152 onto a live time-series chart. It is the UDP twin of the MQTT Live Data Plotter: same chart, same console, same configuration — only the transport differs. It does not know anything about your payload format; you tell it how to pull the numbers out, using one regular expression and one short line of JavaScript per line on the chart.

Nothing about your data leaves this server: the page talks to ajax/udp_monitor.php on iperfect.net, which reads the Node listener over the loopback interface. That is the same path the UDP Monitor tab uses.

• Send to iperfect.net on UDP port 49152. Both fields are fixed — that is the only port the listener service binds.
• Your payload has to be text. Binary bytes are shown as dots in the console and cannot be matched by a regular expression. Send temp=25.5, not a packed struct.
• UDP is fire-and-forget. A datagram can be lost, duplicated or arrive out of order, and nothing tells the sender. Gaps in a line are normal on a busy or distant link — the plotter draws what arrived.
• Keep a datagram under 8 KB; larger ones are dropped before they reach the buffer.
• Use a current Chrome, Edge or Firefox. The page only reads — it never sends anything back to your device.

If nothing is publishing yet, send a datagram by hand and watch it land in the console. Run one of these from any machine with internet access.

Shell — netcat

echo "node1,2340,17,1.42,-0.87,9.61" | nc -u -w1 iperfect.net 49152

Shell — a stream of readings

while true; do
  echo "node1,2340,17,$RANDOM.0,$RANDOM.0,$RANDOM.0" | nc -u -w0 iperfect.net 49152
  sleep 1
done

Python

import socket, time, random
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
while True:
    msg = "node1,2340,17,%.2f,%.2f,%.2f" % (random.uniform(-2, 2),
                                            random.uniform(-2, 2),
                                            random.uniform(8, 11))
    s.sendto(msg.encode(), ("iperfect.net", 49152))
    time.sleep(1)

ESP32 / ESP8266 — Arduino

#include <WiFiUdp.h>
WiFiUDP udp;

void sendReading(float t) {
  udp.beginPacket("iperfect.net", 49152);
  udp.printf("node1,temp=%.2f", t);
  udp.endPacket();
}

1. Start monitoring. Leave Host and UDP Port as they are and press Start Monitoring. The status pill turns green and reads Monitoring :49152.
2. Read one datagram. Send something (see section 3) and copy one line out of the Incoming UDP Datagrams console. Everything after the arrow is what your expressions will see as data.
3. Name your lines. In Axis Configuration set X-Axis data types to plot to how many lines you want, press Apply, then type a name into each row.
4. Write the expressions. In RegEx Configuration set Expressions to plot to one + one per line and press Apply. Row 1 splits the datagram (tick Is RegEx); the rest plot (leave it unticked).
5. Save Configuration. The page reloads with your settings, so press Start Monitoring again. Points appear as datagrams arrive.

Every row in RegEx Configuration runs once per datagram, top to bottom. The Is RegEx tick is what decides how it runs:

What you can use inside a row

Counting the index

/([^|,]+)/g means “every run of characters that is not a comma or a pipe” — in other words, every field. Suppose a datagram reads:

Zone,2340,e1:0b:6f:40:82:fb,17,1.42,-0.87,9.61|ok

Splitting it gives these positions:

So the three numbers you want are regEx[4], regEx[5] and regEx[6]. Do this with a datagram copied from your own console — the layout above is only an illustration of the counting.

Four rules worth remembering

• Put the Is RegEx row first. Rows run in order, so the array has to be filled before anything reads from it.
• Use only one Is RegEx row. A second one replaces the first one's result.
• End each addPoint with ,false. That skips a redraw per point; the chart redraws once after all rows have run, which keeps it smooth when a poll brings in a burst of datagrams.
• Multiply by 1. Matches come out as text. (regEx[4])*1 turns "1.42" into the number 1.42. Without it the point plots as zero or not at all.

This is a complete, working configuration that plots AccelX, AccelY and AccelZ from a node sending the datagram shown above. Copy it field for field.

Read it as: row 1 chops the datagram into fields; rows 2–4 take fields 5, 6 and 7 and push them onto the first, second and third line of the chart, stamped with the arrival time.

Top bar

Connection strip

Chart and console

Configuration

Copy a row, change the index, done.

Splitting rows — tick Is RegEx

Plotting rows — leave Is RegEx unticked

Both read the same listener through the same endpoint. They differ in what they do with what arrives.

A useful pairing: open the monitor first to see the raw shape of a datagram, copy one line out of it, then come here and write the expressions against it.