IoT4H GrovePI Nodes

This project was developed and tested on Raspberry Pi 4 with GrovePi+ on Bullseye (Rasperry Pi OS 11), Node 18.19.1 and npm 10.2.4.

Installation

1. npm install node-red-contrib-grovepi-iot4h (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.

Code Replacement Nodes

1. Save Variable
2. Load Variable
3. Timestamp
4. Comparison Filter
5. Threshold Filter
6. Variable Comparison Filter
7. Moving Average
8. Array Index

Inputs / Sensors

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

Outputs / Actuators

1. LCD RGB-Backlight
2. LED
3. Buzzer

Sensors

1. Analog Output
2. Digital Output

I2C Sensors

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

Troubleshooting

If a sensor returns false instead of a numeric value, check if the red LED on the GrovePI board is on.

In that case, disconnect all sensors from the board, detach the GrovePI board and put it back on.

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