node-red-contrib-thermoservice

Node-RED input node that polls a DS18B20 temperature sensor via the ThermoService HTTP endpoint and emits each reading as a message.

Overview

[thermoservice in] ──► msg.payload  = 21.38   (°C, number)
                       msg.topic    = "10.11.182.89"
                       msg.sensor   = "hostname"
                       msg.rom      = "28-0123456789ab"
                       msg.time     = "2026-05-15T10:00:00.123456"

The node fires on every polling interval. If the sensor is absent or unreachable it logs an error and shows a red status badge — no message is emitted.

Requirements

• Node-RED ≥ 4.0
• A running ThermoService instance exposing a /celsius JSON endpoint
• No extra npm dependencies (uses Node.js built-in http/https)

Installation

From npm

cd ~/.node-red
npm install node-red-contrib-thermoservice

Then restart Node-RED and refresh the browser.

From GitHub

cd ~/.node-red
npm install Vitexus/node-red-contrib-thermoservice

From Debian package (Trixie)

Add the VitexSoftware APT repository and install:

wget -qO- https://repo.vitexsoftware.com/keyring.gpg \
  | sudo tee /usr/share/keyrings/vitexsoftware.gpg >/dev/null
echo "deb [signed-by=/usr/share/keyrings/vitexsoftware.gpg] \
  https://repo.vitexsoftware.com trixie main" \
  | sudo tee /etc/apt/sources.list.d/vitexsoftware.list
sudo apt update && sudo apt install node-red-contrib-thermoservice

Configuration

Double-click the node to open the editor:

Field	Default	Description
Name	(empty)	Optional display label
URL	http://localhost:5000/celsius	Full URL of the ThermoService /celsius endpoint
Interval	60	Polling interval in seconds (minimum: 5)

ThermoService /celsius response format

{
  "rom":         "28-0123456789ab\n",
  "time":        "2026-05-15T10:00:00.123456",
  "sensor":      "pi-hostname",
  "temperature": 21.375
}

When the DS18B20 sensor is absent the response contains "temperature": null and an "error" field — the node emits no message and shows a red status.

Output message

Property	Type	Description
msg.payload	number	Temperature in °C (e.g. 21.375)
msg.topic	string	Sensor hostname
msg.sensor	string	Sensor hostname
msg.rom	string	DS18B20 ROM ID, trimmed (e.g. 28-0123456789ab)
msg.time	string	Measurement timestamp from thermoservice

Node status

Status	Meaning
🟢 21.38 °C	Last reading successful
🔴 no sensor	Endpoint reachable but sensor absent
🔴 conn error	Cannot reach the thermoservice URL
🔴 timeout	HTTP request timed out (10 s limit)
🔴 parse error	Response is not valid JSON

Example flows

Basic example — importovatelný flow

Soubor examples/basic-flow.json obsahuje připravený flow, který lze přímo importovat do Node-RED (☰ → Import → vybrat soubor):

[thermoservice in: DS18B20]
    ├──► [switch: Senzor OK?]
    │        ├── OK ──► [template: Formátuj zprávu] ──► [debug: Výstup]
    │        └── null ──► [debug: Chyba senzoru]
    └──► [debug: Raw msg] (vypnutý)

[
    {
        "id": "tab-thermo-example",
        "type": "tab",
        "label": "ThermoService příklad",
        "disabled": false,
        "info": ""
    },
    {
        "id": "ex-in",
        "type": "thermoservice-in",
        "z": "tab-thermo-example",
        "name": "DS18B20",
        "url": "http://localhost:5000/celsius",
        "interval": 60,
        "x": 160,
        "y": 120,
        "wires": [["ex-switch-err", "ex-debug-raw"]]
    },
    {
        "id": "ex-switch-err",
        "type": "switch",
        "z": "tab-thermo-example",
        "name": "Senzor OK?",
        "property": "payload",
        "propertyType": "msg",
        "rules": [{"t": "nnull"}, {"t": "null"}],
        "checkall": "false",
        "repair": false,
        "outputs": 2,
        "x": 360,
        "y": 120,
        "wires": [["ex-tpl-format"], ["ex-debug-err"]]
    },
    {
        "id": "ex-tpl-format",
        "type": "template",
        "z": "tab-thermo-example",
        "name": "Formátuj zprávu",
        "field": "payload",
        "fieldType": "msg",
        "format": "handlebars",
        "syntax": "mustache",
        "template": "Senzor: {{sensor}}  |  ROM: {{rom}}  |  Teplota: {{payload}} °C",
        "output": "str",
        "x": 570,
        "y": 100,
        "wires": [["ex-debug-out"]]
    },
    {
        "id": "ex-debug-out",
        "type": "debug",
        "z": "tab-thermo-example",
        "name": "Výstup",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": true,
        "complete": "payload",
        "targetType": "msg",
        "x": 780,
        "y": 100,
        "wires": []
    },
    {
        "id": "ex-debug-err",
        "type": "debug",
        "z": "tab-thermo-example",
        "name": "Chyba senzoru",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": true,
        "complete": "payload.error",
        "targetType": "msg",
        "x": 590,
        "y": 140,
        "wires": []
    },
    {
        "id": "ex-debug-raw",
        "type": "debug",
        "z": "tab-thermo-example",
        "name": "Raw msg (vypnutý)",
        "active": false,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "x": 370,
        "y": 200,
        "wires": []
    }
]

Výstup v debug panelu po deployi:

Senzor: pi-hostname  |  ROM: 28-0123456789ab  |  Teplota: 21.375 °C

Rozšířený flow (dashboard + InfluxDB + Teams alert)

Import the ready-made extended flow from nodered-flow.json in the thermoservice repository. It adds a dashboard gauge/chart, InfluxDB storage and a Microsoft Teams alert when temperature drops below 5 °C.

Store in InfluxDB

[thermoservice in] ──► [function: format for InfluxDB] ──► [influxdb out]

Function node body:

msg.payload = [
    { temperature: msg.payload },
    { sensor: msg.sensor, rom: msg.rom }
];
return msg;

Dashboard gauge

Connect msg directly to a ui_gauge node (node-red-dashboard):

• Value format: {{value | number:1}}
• Min / Max: -20 / 50
• Label: °C

Microsoft Teams alert on low temperature

[thermoservice in]
    ──► [switch: payload < 5]
        ──► [delay: rate limit 1/hour]
            ──► [function: build Teams card]
                ──► [http request: POST webhook URL]

Building from source

git clone https://github.com/Vitexus/node-red-contrib-thermoservice
cd node-red-contrib-thermoservice
# No build step needed — pure JS, no dependencies

Build Debian package

Requires devscripts, debhelper, pbuilder and a Debian Trixie chroot:

debuild-pbuilder -r"sudo -E" -i -us -uc -b

The resulting node-red-contrib-thermoservice_*.deb is published via the Jenkins pipeline to https://repo.vitexsoftware.com.

CI / CD

Builds are managed by the Jenkins pipeline at https://jenkins.proxy.spojenet.cz/job/Foregin/job/node-red-contrib-thermoservice/.

The pipeline (debian/Jenkinsfile) builds a .deb for Debian Trixie inside a vitexsoftware/debian:trixie Docker container and publishes it to the VitexSoftware APT repository via Aptly on success.

Related projects

Project	Description
thermoservice	Flask HTTP service that reads DS18B20 via 1-Wire
node-red	Debian packaging of Node-RED 4.x

License

MIT © 2026 Vitex Software