node-red-nodes/hardware/sensehat

node-red-node-pi-sense-hat

A Node-RED node to interact with a Raspberry Pi Sense HAT.

Pre-requisites

The Sense HAT python drivers need to be installed manually:

sudo apt-get update
sudo apt-get install sense-hat
sudo pip-3.2 install pillow

See the driver documentation for more information.

Install

Run the following command in your Node-RED user directory (typically ~/.node-red):

npm install node-red-node-pi-sense-hat

Usage

Input Node

This node sends readings from the various sensors on the Sense HAT, grouped into three sets; motion events, environment events and joystick events.

Motion events

Motion events include readings from the accelerometer, gyroscope and magnetometer, as well as the current compass heading. They are sent at a rate of approximately 10 per second. The topic is set to motion and the payload is an object with the following values:

• acceleration.x/y/z : the acceleration intensity in Gs
• gyroscope.x/y/z : the rotational intensity in radians/s
• orientation.roll/pitch/yaw : the angle of the axis in degrees
• compass : the direction of North in degrees

Environment events

Environment events include readings from the temperature, humidity and pressure sensors. They are sent at a rate of approximately 1 per second. The topic is set to environment and the payload is an object with the following values:

• temperature : degrees Celsius
• humidity : percentage of relative humidity
• pressure : Millibars

Joystick events

Joystick events are sent when the Sense HAT joystick is interacted with. The topic is set to joystick and the payload is an object with the following values:

• key : one of UP, DOWN, LEFT, RIGHT, ENTER
• state : the state of the key:
  • 0 : the key has been released
  • 1 : the key has been pressed
  • 2 : the key is being held down