RM3100 + Pico

This project implements a data collection system for the RM3100 magnetometer using a Raspberry Pi Pico microcontroller. The system captures magnetic field measurements in three axes and streams the data over USB.

Features

• Continuous magnetic field measurements at 75Hz
• Three-axis (X, Y, Z) magnetic field data in microTesla (µT)
• Real-time data streaming over USB
• Data visualization tools
• Built-in LED status indicator
• Automatic sensor reconnection on failure

Hardware Requirements

• Raspberry Pi Pico
• RM3100 Magnetometer
• I2C connection cables

Pin Connections

Pin Function	Pico GPIO	Physical Pin
I2C SDA	GPIO 0	Pin 1
I2C SCL	GPIO 1	Pin 2
LED	GPIO 25	Built-in LED

Pinouts

Raspberry Pi Pico

RM3100 Magnetometer

Software Dependencies

pip3 install -r requirements.txt

• Raspberry Pi Pico SDK
• Python 3.x with the following packages:
  • pyserial
  • pandas
  • matplotlib
  • numpy

Building and Flashing

1. Set up the Pico SDK:

# Update the SDK path in CMakeLists.txt
set(PICO_SDK_PATH "~/pico-sdk")

2. Build the project:

mkdir build
cd build
cmake ..
make

3. Flash the compiled rm3100_magnetometer.uf2 file to your Pico.

Data Collection

1. Find your device port:

ls /dev/tty.*

2. Collect data using either method:

Using Python:

python record_data.py

Or using cu (Unix/Mac):

cu -l /dev/tty.usbmodem1101 -s 115200 > magnetometer_data.csv

Data Format

The device outputs CSV data with the following columns:

• Timestamp(ms): Milliseconds since start
• M_x(µT): X-axis magnetic field
• M_y(µT): Y-axis magnetic field
• M_z(µT): Z-axis magnetic field
• M(µT): Total magnetic field magnitude

Data Visualization

Run the plotting script to visualize the collected data:

python plots.py

This will generate:

• Time series plots for each axis and magnitude
• Basic statistical analysis
• Output plots saved as PNG files

LED Status Indicators

• OFF: Normal operation
• Double Blink + 2s pause: Sensor initialization failure/connection lost

Technical Details

• I2C Address: 0x23
• Sample Rate: 75 Hz
• Cycle Count: 200 (all axes)
• Scale Factor: 1/75 µT/LSB
• USB VID/PID: 0x2E8A/0x000A

Troubleshooting

1. If the LED keeps blinking:

   • Check I2C connections
   • Verify sensor power supply
   • Confirm I2C address matches (0x23)

2. If no data appears:

   • Check USB connection
   • Verify correct port in data collection script
   • Ensure correct baud rate (115200)