README

node-red-contrib-mpu9250

Support for GY-91 (MPU-9250 + BMP280), which provides Acceleration, Gyrometer, Magnetometer & Temperature readings.

Initial Setup

The following has been testing on Raspberry Pi 3B+ running Buster.

# Enable I2C on your Raspberry Pi
# You can do it with raspi-config command, or manually below
echo "dtparam=i2c1=on" | sudo tee -a /boot/config.txt
echo  "dtparam=i2c_arm=on" | sudo tee -a /boot/config.txt
#optional - echo "dtparam=i2c_arm_baudrate=400000" | sudo tee -a /boot/config.txt

# Ensure the following dev modules are loaded
echo  "i2c-bcm2708" | sudo tee -a /etc/modules
echo  "i2c-dev" | sudo tee -a /etc/modules

# Add your user to i2c group so no need sudo later on
sudo usermod -aG i2c $USER

# Install i2c-tools
sudo apt-get install i2c-tools -y

# Reboot your pi, both for the i2c support you activated and for the user access you changed
sudo reboot

# Make sure you see your devices listed with i2cdetect
# You should see it at position 68
i2cdetect -y 1

Testing Setup

You can use the test.js script in the repository to see if everything works.

node test.js

Installation

cd ~/.node-red
npm install /path/to/node-red-contrib-mpu9250

Usage

You will see a node called sensor_mpu9250 in Node-Red, drag drop, and you are good to go. For each method, if you set "stream" property to "true", then the node will keep streaming the readings based on an interval you set. The interval property is called "streamIntervalMs" and is set in milliseconds.

You can connect an Inject node, with a JSON payload to the sensor_mpu9250 node, like the following:

Starts stream and returns all data every 1s: Data returned: Accel.x Accel.y Accel.z Gyro.x Gyro.y Gyro.z Mag.x Mag.y Mag.z Compass.heading Compass.direction Temperature

{
    "method": "getAll",
    "stream": true,
    "streamIntervalMs": 1000
}

Starts stream and returns data every 5s: Data returned: Temperature only

{
    "method": "getTemperatureCelsius",
    "stream": true,
    "streamIntervalMs": 5000
}

Stops stream

{
    "method": "getAll",
    "stream": false
};

Other methods

You can call all the methods of the Wrapper_MPU9250 (see repo). This node is based on the mpu9250 package, you can also call any methods from it using the method "api" of the Wrapper.

Usage no npm install needed!