Complete step-by-step guide for integrating Didactum monitoring devices and sensors into collectd via SNMP – including plugin configuration, RRDtool output, Grafana integration, threshold alarms, and InfluxDB integration.

• Software: collectd 5.x (Ubuntu / Debian)
• Plugin: SNMP Plugin (collectd-snmp)
• Output: RRDtool, InfluxDB, or Graphite (optional)
• Visualization: Grafana (recommended)
• Devices: Didactum Monitoring System 100T / 300T / 500T / 550T
• Sensors: Temperature, leakage, humidity, door contact, smoke

collectd Server

• Ubuntu 20.04 / 22.04 LTS or Debian 11/12
• collectd 5.x installed
• Packages: collectd, collectd-utils, snmp, snmp-mibs-downloader
• UDP port 161 open outbound for SNMP polling
• Network access to the Didactum device

Didactum Device

• Monitoring System 100T, 300T, 500T, or 550T
• SNMP enabled (v1 or v2c – collectd-snmp does not natively support v3)
• MIB file available for download in the web interface

Architecture & Data Flow

[Didactum Monitoring System]
  IP: 192.168.1.50
       |
       | SNMP polling (UDP 161) every 60 seconds
       v
[collectd Daemon]
  /etc/collectd/collectd.conf
       |
       |-- RRDtool  --> /var/lib/collectd/rrd/  (file storage)
       |-- InfluxDB --> localhost    (time-series DB)
       |-- Graphite --> localhost:2003           (alternative)
       v
[Grafana Dashboard]
  localhost

Important collectd Directories

/etc/collectd/collectd.conf        <-- Main configuration
/etc/collectd/collectd.conf.d/     <-- Modular configuration files
/var/lib/collectd/rrd/             <-- RRD database files
/usr/lib/collectd/                 <-- Plugin binaries
/usr/share/doc/collectd-core/      <-- Example configurations

Step 1 – Open Web Interface

Open in browser: 192.168.1.50 (adjust IP of the Didactum device)

Step 2 – Open SNMP Settings

System Settings → SNMP

Step 3 – Enter the Following Values

Note: 

The collectd SNMP plugin natively supports only SNMPv1 and v2c. For SNMPv3, an external wrapper script must be used via the exec plugin.

Step 1 – Install Packages

sudo apt update
sudo apt install -y collectd collectd-utils \\
    snmp snmp-mibs-downloader \\
    librrd-dev rrdtool

Step 2 – Check collectd Version

collectd -h | head -5
# or:
dpkg -l collectd

Step 3 – Enable collectd Service at System Startup

sudo systemctl enable collectd
sudo systemctl start collectd
sudo systemctl status collectd

Step 1 – Download MIB File from the Didactum Web Interface

System Settings → SNMP → "Download MIB File" → didactum.mib

Step 2 – Install MIB on the collectd Server

sudo cp didactum.mib /usr/share/snmp/mibs/

# SNMP configuration for MIB usage
echo "mibdirs /usr/share/snmp/mibs" | sudo tee -a /etc/snmp/snmp.conf
echo "mibs ALL" | sudo tee -a /etc/snmp/snmp.conf

Step 3 – Test SNMP Connection

# List all sensor values
snmpwalk -v 2c -c didactum_collectd 192.168.1.50 \\
    .1.3.6.1.4.1.46501.5.1.1

# Query a single temperature value (raw value ÷ 10 = degrees Celsius)
snmpget -v 2c -c didactum_collectd 192.168.1.50 \\
    .1.3.6.1.4.1.46501.5.1.1.7.101001

# Query leakage status (0=dry, 1=water detected)
snmpget -v 2c -c didactum_collectd 192.168.1.50 \\
    .1.3.6.1.4.1.46501.5.1.1.7.107001

If values appear without error messages, the SNMP connection is ready for collectd.

Step 1 – Create Configuration File for Didactum

sudo nano /etc/collectd/collectd.conf.d/didactum-snmp.conf

Step 2 – Insert the Following Content

# ================================================================
# collectd SNMP plugin – Didactum Monitoring System
# File: /etc/collectd/collectd.conf.d/didactum-snmp.conf
# ================================================================

LoadPlugin snmp

<Plugin snmp>

  # --------------------------------------------------------------
  # DATA blocks: Definition of the metrics to be queried
  # These blocks describe WHAT is queried.
  # The Host block defines WHERE the query is performed.
  # --------------------------------------------------------------

  # --- Temperature sensor (digital, sensor ID 101001) ------------
  # Scale 0.1: raw value ÷ 10 = degrees Celsius (235 = 23.5 °C)
  <Data "didactum_temp_01">
    Type        "temperature"
    Table       false
    Instance    "sensor_temperature_01"
    Values      ".1.3.6.1.4.1.46501.5.1.1.7.101001"
    Scale       0.1
  </Data>

  # --- Temperature sensor status (0=OK, 1=Alarm, 2=No signal) ---
  <Data "didactum_temp_status_01">
    Type        "gauge"
    Table       false
    Instance    "sensor_temp_status_01"
    Values      ".1.3.6.1.4.1.46501.5.1.1.6.101001"
  </Data>

  # --- Leakage sensor (0=dry, 1=water detected) ------------------
  <Data "didactum_leak_01">
    Type        "gauge"
    Table       false
    Instance    "sensor_leakage_01"
    Values      ".1.3.6.1.4.1.46501.5.1.1.7.107001"
  </Data>

  # --- Leakage sensor status -------------------------------------
  <Data "didactum_leak_status_01">
    Type        "gauge"
    Table       false
    Instance    "sensor_leakage_status_01"
    Values      ".1.3.6.1.4.1.46501.5.1.1.6.107001"
  </Data>

  # --- Humidity sensor (value in %) ------------------------------
  <Data "didactum_hum_01">
    Type        "humidity"
    Table       false
    Instance    "sensor_humidity_01"
    Values      ".1.3.6.1.4.1.46501.5.1.1.7.102001"
  </Data>

  # --- Door contact (0=closed, 1=open) ---------------------------
  <Data "didactum_door_01">
    Type        "gauge"
    Table       false
    Instance    "sensor_door_01"
    Values      ".1.3.6.1.4.1.46501.5.1.1.7.104001"
  </Data>

  # --- Smoke detector (0=OK, 1=alarm) ----------------------------
  <Data "didactum_smoke_01">
    Type        "gauge"
    Table       false
    Instance    "sensor_smoke_01"
    Values      ".1.3.6.1.4.1.46501.5.1.1.7.106001"
  </Data>

  # --- Analog temperature sensor (newer models OID 39052) --------
  <Data "didactum_temp_analog_01">
    Type        "temperature"
    Table       false
    Instance    "sensor_temp_analog_01"
    Values      ".1.3.6.1.4.1.39052.5.2.1.7.201001"
    Scale       0.1
  </Data>

  # --------------------------------------------------------------
  # HOST block: Connection parameters to the Didactum device
  # This block defines WHERE and HOW the query is performed.
  # --------------------------------------------------------------

  <Host "didactum-monitor-01">
    Address     "192.168.1.50"
    Version     2
    Community   "didactum_collectd"
    Interval    60           # polling interval in seconds
    Timeout     5            # timeout in seconds
    Retries     3            # number of retry attempts

    # Query all defined Data blocks:
    Collect "didactum_temp_01"
    Collect "didactum_temp_status_01"
    Collect "didactum_leak_01"
    Collect "didactum_leak_status_01"
    Collect "didactum_hum_01"
    Collect "didactum_door_01"
    Collect "didactum_smoke_01"
    Collect "didactum_temp_analog_01"
  </Host>

  # --------------------------------------------------------------
  # Second device (commented out – enable if needed)
  # --------------------------------------------------------------
  # <Host "didactum-monitor-02">
  #   Address   "192.168.1.51"
  #   Version   2
  #   Community "didactum_collectd"
  #   Interval  60
  #   Collect   "didactum_temp_01"
  #   Collect   "didactum_leak_01"
  # </Host>

</Plugin>

Step 3 – Ensure the SNMP Plugin Is Loaded in the Main Configuration

sudo nano /etc/collectd/collectd.conf

Check whether the following line exists and is not commented out:

LoadPlugin snmp

If modular configuration is enabled, ensure that the conf.d directory is included:

Include "/etc/collectd/collectd.conf.d/*.conf"

Step 4 – Register Custom Types for Leakage and Status (optional)

collectd already knows the gauge type. For cleaner naming, a custom types.db extension can be created:

sudo nano /etc/collectd/didactum-types.db

# Didactum custom types
# Format: type_name  ds_name:ds_type:min:max
leakage_status   value:GAUGE:0:2
door_status      value:GAUGE:0:1
smoke_status     value:GAUGE:0:1
sensor_status    value:GAUGE:0:2

Include it in collectd.conf:

TypesDB "/usr/share/collectd/types.db"
TypesDB "/etc/collectd/didactum-types.db"

Option A – RRDtool (local file storage)

sudo nano /etc/collectd/collectd.conf

# Enable RRDtool plugin
LoadPlugin rrdtool
<Plugin rrdtool>
  DataDir     "/var/lib/collectd/rrd"
  CacheTimeout 120
  CacheFlush   900
  WritesPerSecond 50
</Plugin>

Create directory:

sudo mkdir -p /var/lib/collectd/rrd
sudo chown collectd:collectd /var/lib/collectd/rrd

RRD files are automatically created under the following path:

/var/lib/collectd/rrd/didactum-monitor-01/snmp/
  temperature-sensor_temperatur_01.rrd
  gauge-sensor_leckage_01.rrd
  humidity-sensor_feuchte_01.rrd
  gauge-sensor_tuer_01.rrd
  gauge-sensor_rauch_01.rrd

Option B – InfluxDB (recommended for Grafana)

# collectd plugin for InfluxDB output
LoadPlugin network

<Plugin network>
  <Server "192.168.1.10" "25826">
    SecurityLevel "None"
  </Server>
</Plugin>

Enable the collectd input in the InfluxDB configuration:

# /etc/influxdb/influxdb.conf
[[collectd]]
  enabled = true
  bind-address = ":25826"
  database = "collectd"
  typesdb = "/usr/share/collectd/types.db"

Option C – CSV output (for simple evaluation)

LoadPlugin csv

<Plugin csv>
  DataDir "/var/lib/collectd/csv"
  StoreRates true
</Plugin>

Option D – Write-HTTP (for external systems)

LoadPlugin write_http

<Plugin write_http>
  <Node "didactum-backend">
    URL "http://192.168.1.20:9999/collectd"
    Format "JSON"
    StoreRates false
  </Node>
</Plugin>

The threshold plugin monitors collected values against defined limits and sends notifications when thresholds are exceeded.

Step 1 – Enable Threshold Plugin

sudo nano /etc/collectd/collectd.conf

LoadPlugin threshold

Step 2 – Create Threshold Configuration File

sudo nano /etc/collectd/collectd.conf.d/didactum-thresholds.conf

# ================================================================
# collectd threshold configuration – Didactum sensors
# File: /etc/collectd/collectd.conf.d/didactum-thresholds.conf
# ================================================================
LoadPlugin threshold
<Plugin threshold>
  # --------------------------------------------------------------
  # Host-specific thresholds for Didactum Monitor 01
  # --------------------------------------------------------------
  <Host "didactum-monitor-01">
    # --- Temperature sensor -------------------------------------
    # Scale has already been set to 0.1 in the SNMP configuration
    # Therefore we work directly with Celsius values here
    <Type "temperature">
      Instance        "sensor_temperatur_01"
      WarningMax      28.0    # Warning at 28.0 °C
      FailureMax      35.0    # Critical at 35.0 °C
      WarningMin      5.0     # Warning below 5.0 °C (too cold)
      FailureMin      2.0     # Critical below 2.0 °C
      Persist         true    # Repeat alarm for each measurement
      PersistOK       false   # No OK message for each value
    </Type>
    # --- Leakage sensor -----------------------------------------
    # Value 1 = water detected = immediately critical
    <Type "gauge">
      Instance        "sensor_leckage_01"
      FailureMax      0.5     # From 0.5 (= water detected) critical
      Persist         true    # Repeat alarm while water present
      Invert          false
    </Type>
    # --- Leakage status -----------------------------------------
    <Type "gauge">
      Instance        "sensor_leckage_status_01"
      FailureMax      0.5     # Status > 0 = alarm or error
      Persist         true
    </Type>
    # --- Humidity -----------------------------------------------
    <Type "humidity">
      Instance        "sensor_feuchte_01"
      WarningMax      80.0    # Warning at 80 %
      FailureMax      90.0    # Critical at 90 %
      WarningMin      20.0    # Warning below 20 %
      FailureMin      10.0    # Critical below 10 %
      Persist         false
    </Type>
    # --- Door contact -------------------------------------------
    # 1 = door open = warning
    <Type "gauge">
      Instance        "sensor_tuer_01"
      WarningMax      0.5     # From 0.5 (= open) warning
      Persist         true    # Repeat alarm while open
    </Type>
    # --- Smoke detector -----------------------------------------
    # 1 = smoke = immediately critical
    <Type "gauge">
      Instance        "sensor_rauch_01"
      FailureMax      0.5     # From 0.5 (= alarm) critical
      Persist         true
    </Type>
    # --- Temperature sensor status ------------------------------
    # 0=OK, 1=Alarm, 2=No signal
    <Type "gauge">
      Instance        "sensor_temp_status_01"
      FailureMax      0.5     # Any value > 0 is a problem
      Persist         true
    </Type>
  </Host>
</Plugin>

Option A – notify_email plugin (direct, simple)

sudo nano /etc/collectd/collectd.conf.d/didactum-notify.conf

# Email notification on threshold breach
LoadPlugin notify_email
<Plugin notify_email>
  SMTPServer    "mail.yourdomain.com"
  SMTPPort      587
  SMTPUser      "collectd@yourdomain.com"
  SMTPPassword  "YourMailPassword"
  From          "collectd@yourdomain.com"
  # Recipients (multiple possible):
  Recipient     "admin@yourdomain.com"
  # Subject prefix:
  Subject       "[Didactum ALARM] %s"
</Plugin>

Option B – exec plugin with custom notification script

sudo nano /etc/collectd/collectd.conf.d/didactum-exec.conf

LoadPlugin exec
<Plugin exec>
  # Call notification script when threshold is triggered
  NotificationExec "collectd" "/etc/collectd/scripts/didactum-alarm.sh"
</Plugin>

Create alarm script:

sudo mkdir -p /etc/collectd/scripts
sudo nano /etc/collectd/scripts/didactum-alarm.sh

#!/bin/bash
# ================================================================
# Didactum alarm script for collectd
# Called when a threshold is exceeded
# ================================================================
# Notification variables are set by collectd:
# NOTIF_SEVERITY  = FAILURE | WARNING | OKAY
# NOTIF_HOST      = Hostname
# NOTIF_PLUGIN    = Plugin name
# NOTIF_TYPE      = Metric type
# NOTIF_INSTANCE  = Instance name
# NOTIF_MESSAGE   = Error message
# Send mail only on FAILURE or WARNING
if [ "$NOTIF_SEVERITY" = "OKAY" ]; then
  exit 0
fi
RECIPIENT="admin@yourdomain.com"
SENDER="collectd@yourdomain.com"
SUBJECT="[Didactum $NOTIF_SEVERITY] $NOTIF_HOST – $NOTIF_TYPE ($NOTIF_INSTANCE)"
MESSAGE="
Didactum Sensor Alarm
=====================
Timestamp:  $(date '+%Y-%m-%d %H:%M:%S')
Severity:   $NOTIF_SEVERITY
Host:       $NOTIF_HOST
Plugin:     $NOTIF_PLUGIN
Type:       $NOTIF_TYPE
Instance:   $NOTIF_INSTANCE
Message:    $NOTIF_MESSAGE
"
echo "$MESSAGE" | mail -s "$SUBJECT" -r "$SENDER" "$RECIPIENT"

sudo chmod +x /etc/collectd/scripts/didactum-alarm.sh
sudo chown collectd:collectd /etc/collectd/scripts/didactum-alarm.sh

Ensure mail delivery (Postfix) on the server:

sudo apt install postfix mailutils -y
echo "Test mail collectd" | mail -s "Test" admin@yourdomain.com

Step 1 – Install Grafana (if not already installed)

sudo apt install -y software-properties-common
sudo apt install -y grafana
sudo systemctl enable grafana-server
sudo systemctl start grafana-server
# Grafana reachable at: [http://192.168.1.10:3000](http://192.168.1.10:3000)
# Default login: admin / admin

Step 2 – Configure Data Source

Option A: RRDtool data source

Grafana → Configuration → Data Sources → Add data source
→ Select SimpleJSON or collectd-RRD plugin
→ URL: localhost (install RRD proxy)

Option B: InfluxDB data source (recommended)

Grafana → Configuration → Data Sources → Add data source → InfluxDB
  URL:        localhost
  Database:   collectd
  HTTP Method: GET
→ Save & Test

Step 3 – Create New Dashboard

Grafana → + → Dashboard → Add new panel

Step 4 – Panel for Temperature Trend

InfluxDB query for Grafana:

SELECT mean("value") FROM "temperature"
WHERE ("host" = 'didactum-monitor-01'
  AND "type_instance" = 'sensor_temperatur_01')
  AND $timeFilter
GROUP BY time($__interval) fill(null)

Step 5 – Panel for Leakage Status

SELECT last("value") FROM "gauge"
WHERE ("host" = 'didactum-monitor-01'
  AND "type_instance" = 'sensor_leckage_01')
  AND $timeFilter

Step 6 – Panel for Humidity

SELECT mean("value") FROM "humidity"
WHERE ("host" = 'didactum-monitor-01'
  AND "type_instance" = 'sensor_feuchte_01')
  AND $timeFilter
GROUP BY time($__interval) fill(null)

Step 7 – Save Dashboard

Top right: Save icon → Name: "Didactum Monitoring" → Save

All Didactum OIDs begin with .1.3.6.1.4.1.46501 (older firmware) or .1.3.6.1.4.1.39052 (newer models). The sensor ID is appended at the end.

OID Fields per Sensor

Sensor Types with OIDs and collectd Configuration

Find the sensor ID: 

In the Didactum web interface under System Tree → Select sensor → Details. This ID is appended to the end of the OID.

Scale option in collectd: 

The Scale 0.1 parameter in the Data block causes collectd to automatically divide the raw value by 10. This stores 235 directly as 23.5 – correct display in Grafana without manual conversion.

MIB prefix by model: 

Older devices use .1.3.6.1.4.1.46501, newer models may use .1.3.6.1.4.1.39052. Refer to the MIB file of your device for the exact OIDs.

Test Configuration Without Starting the Daemon

# Check configuration for syntax errors
sudo collectd -t -C /etc/collectd/collectd.conf

# Start collectd in the foreground with verbose output
sudo collectd -f -C /etc/collectd/collectd.conf
# Stop with Ctrl+C

Restart collectd Service & Check Status

sudo systemctl restart collectd
sudo systemctl status collectd
sudo journalctl -u collectd -f --since "5 minutes ago"

Check RRD Files

# Check whether RRD files have been created
ls -la /var/lib/collectd/rrd/didactum-monitor-01/

# Show the last value of an RRD file
rrdtool lastupdate \\
    /var/lib/collectd/rrd/didactum-monitor-01/snmp/\\
temperature-sensor_temperatur_01.rrd

# Generate a quick graph (last hour)
rrdtool graph /tmp/temp_test.png \\
    --start -3600 \\
    --title "Didactum Temperature" \\
    --vertical-label "Degrees Celsius" \\
    DEF:temp=/var/lib/collectd/rrd/didactum-monitor-01/snmp/\\
temperature-sensor_temperatur_01.rrd:value:AVERAGE \\
    LINE1:temp#FF0000:"Temperature"

Test SNMP Connection Directly

snmpwalk -v 2c -c didactum_collectd 192.168.1.50 \\
    .1.3.6.1.4.1.46501.5.1.1

Error Messages and Solutions

View collectd Log

# Systemd journal
sudo journalctl -u collectd -f

# Direct log file (if syslog plugin is active)
sudo tail -f /var/log/syslog | grep collectd

# Enable verbose logging in collectd.conf:
# LoadPlugin logfile
# <Plugin logfile>
#   LogLevel debug
#   File "/var/log/collectd.log"
# </Plugin>

Didactum Device

• SNMP enabled (v2c)
• Community string set (not "public")
• Trap receiver IP entered (optional)
• MIB file downloaded
• snmpwalk test from the collectd server successful

collectd Server – Packages & MIB

• Packages collectd, collectd-utils, snmp, snmp-mibs-downloader installed
• MIB file saved under /usr/share/snmp/mibs/
• /etc/snmp/snmp.conf: mibs ALL entered
• collectd service running: systemctl status collectd

SNMP Plugin Configuration

• File /etc/collectd/collectd.conf.d/didactum-snmp.conf created
• Data blocks defined for all sensor types
• Scale 0.1 set for temperature sensors
• Host block entered with correct IP and community
• Collect instructions present for all data blocks
• Configuration validated with collectd -t (no errors)

Output & Visualization

• RRDtool plugin configured and RRD files are being created
• Alternatively: InfluxDB integration set up
• Grafana data source connected
• Dashboard with temperature and leakage panels created
• Temperature display in °C correct (Scale 0.1 applied)

Alarms & Notification

• Threshold plugin enabled and configured
• Thresholds set for temperature (warning 28°C, critical 35°C)
• Threshold set for leakage (critical from 0.5)
• Email plugin (notify_email or exec) configured
• Test message received by email