node-red-contrib-dht-sensor 0.0.21

Node-red node for node-dht-sensor

npm install node-red-contrib-dht-sensor

This is a Node Red node to manage connection to a DHT11 or DHT22 sensor on a Raspberry Pi. It allows you to specify the variables that define the connections to the sensor.

This node is added to the Raspberry Pi section.

Installation

This node requires that node-dht-sensor is installed and accessible from Node Red. Since this requires accesss to low-level parts of the Raspberry Pi, you must run your flow with superuser access.

Installing this node requires three steps:

  • Install the BCM2835 library from here.
  • Install the node-dht-sensor dependency
    sudo npm install -g node-dht-sensor
    
  • Install this node
    sudo npm install -g node-red-contrib-dht-sensor
    

Configuring the node

You can specify the following, as seen in the picture here:

  • The topic of the message - this is passed through so it can be used as an ID for the sensor.
  • The name of the node. This can be a unique value to tag the sensor, useful if you have multiple sensors connected.
  • The sensor type - this can be either DHT11 or DHT22.
  • The pin number scheme. This can be any of
    • the BCM-GPIO scheme
    • the physical sequence number, for revision 1 of the Pi
    • the physical sequence number, for revision 2 of the Pi (and A+ or B+)
    • the wiringpi sequence, for revision 1 of the Pi
    • the wiringpi sequence, for revision 2 of the Pi (and A+ or B+)

Node configuration

Using the node

The node is added to the Raspberry Pi section of the Node-RED pallette, and it can be used in a flow as usual:

Node-RED flow

The message returned includes the temperature as the payload, and the humidity and the device ID as part of the message itself:

Returned message

Notes:

  • The temperature values is in °C and the humidity values are % relative humidity.
  • If you're using an older release of Raspbian, you will have to run node-RED as root, otherwise you may run into problems with permissions.

Node Info

Version: 0.0.21
Updated 2 months, 1 week ago
License: Apache 2.0

Downloads

21 in the last day
154 in the last week
605 in the last month

Nodes

  • rpi-dht22

Keywords

  • node-red
  • sensor
  • dht11
  • dht22

Maintainers

  • bpmurray