DS18B20 Sensor Node-RED node for Raspberry Pi

Node-RED node for working with DS18B20 sensors, inspired in this library, but modified to behave slightly different with some extra functionalities.

It is compatible only with RaspberryPi hardware and it only reads the temperature values from sensors. The base library is a npm module, which handles with the whole 1-Wire protocol with DS18B20 sensors (aka it does the magic).

• NPM site: https://www.npmjs.com/package/node-red-contrib-sensor-ds18b20-dynamic-sensor-id

Physical Connection of sensor(s)

The DS18B20 sensors must be connected on GPIO4 (or physical pin #7) because this is the only pin that supports native 1-Wire protocol. The scheme of connection is typically the one on the image below.

Requirements

On the Linux system where your Node-RED is running and where your sensors are connected to, make sure you have loaded all the kernel modules needed for working with 1-Wire devices, what the DS1820 sensor is. Thus, you need to active or have activated the 1-Wire Interface on the Rpi. To do this just go to the Raspi-Configuration page with:

sudo raspi-config

Go to Interfaces and then to 1-Wire and enable it and reboot the device. You are done.

Installation

Run the following command in the root directory of your Node-RED install

npm install node-red-contrib-sensor-ds18b20-dynamic-sensor-id

Or just use the package manager(or manage pallette) from the Node-Red Interface to search for this module and install it manually.

Features

• You can select a 1-wire device/sensor from a dropdown list in the configuration dialog of the node
• Configurable time interval of the sensor sampling (in seconds)
• Periodic sensor sampling can be disabled, and sample temperature only when an external message arrives.
• If 'msg.sensorId' is set, then will be used instead of the configured sensor id.