scanengine-3/pypewpewhops

PyPewPewHOPS - Coherent HOPS Laser Control Library

Python library for controlling Coherent HOPS laser systems via I2C protocol through an FTDI FT2232C USB interface.

Features

• Complete implementation of all documented I2C commands
• Support for system information queries
• Temperature monitoring and control for all sensors
• Power and current control
• Digital I/O operations
• Configuration register access
• Context manager support for safe resource handling
• Dummy laser simulator for development without hardware
• Comprehensive error handling

Installation

Requirements

• Python 3.7+
• FTDI FT2232C USB device
• libftdi library (for Linux)

Install Dependencies

pip install -r requirements.txt

Linux Setup

On Linux, you may need to install libftdi:

# Debian/Ubuntu
sudo apt install libftdi-dev

# Fedora
sudo dnf install libftdi-devel

You may also need to add your user to the appropriate group:

sudo usermod -a -G dialout $USER
sudo usermod -a -G plugdev $USER

Then log out and log back in for the changes to take effect.

Quick Start

Using the Simulator (No Hardware)

from coherent_hops_laser import DummyLaser

with DummyLaser() as laser:
    # Query system information
    info = laser.get_system_info()
    print(f"Model: {info.laser_model}")
    print(f"Wavelength: {info.wavelength}")

    # Monitor temperatures
    temps = laser.get_all_temperatures()
    print(f"Main temperature: {temps.main}°C")

    # Control power
    laser.set_power_command(100.0)
    power = laser.get_power_command()
    print(f"Power set to: {power} mW")

Using Real Hardware

from coherent_hops_laser import CoherentHOPSLaser, I2CMode

# Initialize laser controller
laser = CoherentHOPSLaser(
    slave_address=0x50,           # I2C slave address
    i2c_mode=I2CMode.STANDARD     # 100 kHz
)

# Connect to FTDI device
laser.connect('ftdi://ftdi:2232/1')

try:
    # Query laser model
    model = laser.get_laser_model()
    print(f"Laser Model: {model}")

    # Get all temperatures
    temps = laser.get_all_temperatures()
    print(f"Temperatures: {temps}")

    # Set power
    laser.set_power_command(50.0)

    # Check control mode
    mode = laser.get_control_mode()
    print(f"Control Mode: {mode}")

finally:
    laser.disconnect()

Using Context Manager

from coherent_hops_laser import CoherentHOPSLaser

with CoherentHOPSLaser() as laser:
    laser.connect()

    # Your laser control code here
    info = laser.get_system_info()
    print(info)

# Automatically disconnects

Available Commands

System Information

• get_hardware_id() - Hardware ID
• get_head_type() - Head type
• get_head_board_revision() - PCB revision
• get_laser_model() - Laser model (G532, Tina, Mini00, MiniX)
• get_power_units() - Power units (mW, W)
• get_wavelength() - Wavelength (e.g., 532nm)
• get_system_info() - All system info at once

Temperature Monitoring

• get_temperature_main() - Main heatsink temperature
• get_temperature_brf() - BRF temperature
• get_temperature_shg() - SHG temperature
• get_temperature_thg() - THG temperature
• get_temperature_eta() - ETA temperature
• get_all_temperatures() - All temperatures at once

Temperature Control

• get_temperature_setpoint_main() / set_temperature_setpoint_main(temp)
• get_temperature_setpoint_brf() / set_temperature_setpoint_brf(temp)
• get_temperature_setpoint_shg() / set_temperature_setpoint_shg(temp)
• get_temperature_setpoint_thg() / set_temperature_setpoint_thg(temp)
• get_temperature_setpoint_eta() / set_temperature_setpoint_eta(temp)

Power Control

• get_power_command() / set_power_command(power) - Get/set power
• get_power_memory() - Stored power settings
• get_power_limits() - Power limits

Current Control

• get_current_command() / set_current_command(current) - Get/set current
• get_current_limits() - Current limits
• get_control_mode() / set_control_mode(mode) - Control mode (POWER/CURRENT)

Status Monitoring

• get_key_switch_status() - Key switch status
• get_fan_status() / set_fan_control(value) - Fan control
• get_interlock_status() - Interlock status
• get_remote_control_status() - Remote control status
• get_analog_values() - Analog sensor values

Configuration

• get_config_register_0() / set_config_register_0(value)
• get_config_register_1() / set_config_register_1(value)
• get_config_register_2() / set_config_register_2(value)
• get_config_register_3() / set_config_register_3(value)

See the API documentation for complete command reference.

Examples

Run the example script:

# Simulation mode (no hardware)
python3 example_usage.py 1

# Real hardware mode
python3 example_usage.py 2

# Continuous monitoring
python3 example_usage.py 3

Or run the built-in test:

python3 coherent_hops_laser.py

Continuous Monitoring Example

from coherent_hops_laser import CoherentHOPSLaser
import time

with CoherentHOPSLaser() as laser:
    laser.connect()

    while True:
        temps = laser.get_all_temperatures()
        power = laser.get_power_command()

        print(f"Main: {temps.main:.1f}°C  Power: {power:.1f}mW")
        time.sleep(1)

Troubleshooting

Cannot find FTDI device

# Check if device is connected
lsusb | grep FTDI

# Should show something like:
# Bus 001 Device 005: ID 0403:6010 Future Technology Devices International, Ltd FT2232C

Permission denied

Add your user to the dialout/plugdev group:

sudo usermod -a -G dialout $USER
sudo usermod -a -G plugdev $USER

Then log out and back in.

I2C communication errors

• Verify correct slave address (default: 0x50)
• Check I2C speed (try I2CMode.STANDARD instead of FAST)
• Verify physical connections
• Check for other devices on the bus

Import errors

# Install pyftdi
pip install pyftdi

# If that fails, try:
pip install --user pyftdi

Architecture

• CoherentHOPSLaser: Main class for real hardware control
• DummyLaser: Simulator for development without hardware
• I2CController: Low-level FTDI I2C communication (from pyftdi)
• LaserInfo / TemperatureStatus: Data classes for structured responses

Safety Notes

• Always verify power levels before enabling laser output
• Monitor temperatures during operation
• Check interlock status before operation
• Use appropriate laser safety equipment
• Follow all manufacturer safety guidelines

License

This implementation is based on the Coherent HOPS Demo v2.0.7 protocol documentation.

References

• FTDI MPSSE Documentation: https://ftdichip.com/software-examples/mpsse-projects/
• PyFTDI: https://github.com/eblot/pyftdi
• Original Protocol Documentation: LASER_I2C_PROTOCOL.md