node-red-contrib-sensor-ds18b20
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Node-RED node to get temperature in centigrades from DS18B20 sensors
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# DS18B20 Sensor Node-RED node for Raspberry Pi
Node-RED node for working with [DS18B20 sensors](https://www.maximintegrated.com/en/products/analog/sensors-and-sensor-interface/DS18B20.html), inspired in this [library](https://github.com/stibi/node-red-contrib-ds18b20), 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](https://www.npmjs.com/package/ds18b20) 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
* Historic downloads statistics: https://npm-stat.com/charts.html?package=node-red-contrib-sensor-ds18b20&from=2017-01-23&to=2022-01-23
### 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
```
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.
