IoT4H GrovePI Nodes

This project was developed and tested on Raspberry Pi 4 with GrovePi+ on Debian Trixie (Rasperry Pi OS 13), Node v24.11.1, npm v11.6.2 and Node-RED v4.1.1.

Installation

1. npm install node-red-contrib-iot4h-grovepi (in /home/pi/.node-red/node_modules/)
2. node-red-restart

Nodes

See https://www.dexterindustries.com/GrovePi/engineering/port-description/

In addition to a node for each of the most common sensors, there are four “general” nodes.

1. Digital Input, values: 0 or 1
2. Analog Input, values: 0 to 1023
3. Digital Output, values: 0 or 1
4. Analog Output, values: 0 to 255

msg Properties

See https://nodered.org/docs/user-guide/messages

Usually, the "value" of a message is stored in its payload field. To make integration with other nodes easy, the payload of a sensor message only contains its values, all additional information is stored in other properties.

If a sensor returns multiple values (e.g. temperature and humidity), msg.payload is an array of these values.

In addition to that, msg.valueTypes is an array of value type specifications {unit: ..., name: ..., type: ...}.

This additional information is used for displaying sensor values on the LCD and when sending datapoints to the OpenDash platform.

The name and id values used in the open.DASH JSON object are stored in msg.sensorname and msg.sensorid.

user is set by the "RMQ Output" node and uses the "Username" value entered in the node configuration.

“Event Mode”

For some sensors, like the button, it might be useful to send an event only when the sensor value changes.

To do so, set the reading interval to a low value (e.g. 200ms), then connect the sensor to a "rbe" node.

This node only lets messages through if their payload has changed. It can be found at the bottom of the "Functions" section.

Inputs / Sensors

1. Button
2. Switch
3. Rotary Angle
4. Potentiometer
5. DTH11 Temperature & Humidity
6. DTH21 Temperature & Humidity
7. DTH22 Temperature & Humidity
8. Analog Input
9. Digital Input
10. Water
11. Moisture
12. Piezo Vibration
13. Gas
14. Ultrasonic Ranger
15. Air Quality
16. Light

Outputs / Actuators

1. LCD RGB-Backlight
2. LED
3. PWM LED
4. Buzzer
5. Analog Output
6. Digital Output

I2C Sensors

When connecting a I2C sensor, it doesn't matter which pin is used.

Troubleshooting

Make sure that SPI and I2C are enabled in raspi-config to prevent errors when reading sensor data.

Credits

Package contents obtained in part from node-red-contrib-od-grovepi and extended with own nodes for easier access to complex functionality. The main purpose is to avoid using written code at all.

Salvaged packages for existing sensor nodes for NodeRed:

• https://github.com/memetolsen/node-red-grovepi-nodes
• https://github.com/O-Hahn/node-red-contrib-grovepi
• https://github.com/DexterInd/GrovePi/tree/master/Software/NodeJS
• https://github.com/ia-cloud/GrovePi
• https://www.npmjs.com/package/node-red-contrib-od-grovepi
• https://www.npmjs.com/package/node-red-contrib-grovepi-nodes?activeTab=code