Serial Trigger Interface

This repository contains guiding examples for sending trigger signals via serial communication to Biosemi trigger interface and Arduino devices. While an utility class is provided for each device, it's also possible to achieve the same functionality using the serial.Serial object directly, in a simpler way. (See last example in SerialTriggerBiosemi_example.py)

It's particularly useful for experimental setups requiring precise timing and trigger signals. Some examples on how to send bytes to the interfaces are provided in the how_to_byte_python.ipynb notebook.

The setup and scripts were tested with an oscilloscope. Biosemi trigger interface results in a 3.3V pulse of 8ms duration, and the Arduino trigger interface can be modified as desired (see trigger_pulse_5ms_arduino/ for example code).

What is in here?

• Utility classes for Biosemi and Arduino trigger interfaces, based on the pyserial library.
• Example scripts for sending trigger signals.
• Thread-safe operations
• Comprehensive examples and documentation.

Installation

1. Install the required Python package:

pip install serial

2. For Arduino setup:
   • Connect your Arduino to your computer via USB
   • Upload the trigger_pulse_5ms_arduino.ino sketch to your Arduino via the Arduino IDE.

Usage

Finding Your Serial Port

• On Linux/Mac: Run ls /dev/tty* in terminal
• On Windows: Check Device Manager or run python -m serial.tools.list_ports in terminal

Biosemi Trigger Interface (Check SerialTriggerBiosemi.py for more details)

from SerialTriggerBiosemi import BiosemiTrigger
# Initialize the trigger interface
biosemi = BiosemiTrigger("COM7", initial_delay=3) # Adjust port as needed
# Test the connection
biosemi.test_trigger(signal_byte=0b00000001) # Activates trigger 1
# Don't forget to close the connection
biosemi.close()

Arduino Trigger Interface (Check SerialTriggerArduino.py for more details)

from SerialTriggerArduino import ArduinoTrigger
# Initialize the trigger interface
arduino = ArduinoTrigger("COM8") # Adjust port as needed
# Send trigger signals
arduino.send_signal(True) # HIGH signal
arduino.send_signal(False) # LOW signal
# Close the connection
arduino.close()

File Structure

• SerialTriggerBiosemi.py - Main class for Biosemi trigger interface
• SerialTriggerArduino.py - Main class for Arduino trigger interface
• SerialTriggerBiosemi_example.py - Example usage for Biosemi
• SerialTriggerArduino_example.py - Example usage for Arduino
• trigger_pulse_5ms_arduino/ - Arduino sketch for trigger functionality
• how_to_byte_python.ipynb - Jupyter notebook explaining byte handling in Python

Technical Details

Biosemi Interface

• Supports 8-bit trigger signals
• 3.3V output
• 8ms trigger pulse duration
• Configurable trigger patterns
• Thread-safe operations available

Arduino Interface

• 5V output (modifiable: You can experiment with PWM analogWrite() function)
• 5ms pulse duration (modifiable: Change delay between signals)
• Simple HIGH/LOW triggering
• Visual feedback via built-in LED