A compact and efficient USB-powered controller designed to handle two independent Iris shutters by Thorlabs. This project offers an alternative solution that avoids heat dissipation, sending only the necessary current pulses to open or close the shutter. This alternative is suitable for low actuation rates (~1Hz), where timing accuracy matters.
- Easy-to-use USB interface for power and control
- Open-source design for customization
- Programmable coordinated channels for two Iris shutters
- Python library
- Improved energy efficiency by avoiding continuous heat dissipation
- Internal clock calibration for accurate timings
- Half-microsecond resolution on timings
- Timing of the iris movements via sensor feedback
- One or Two Thorlabs Iris shutters
- USB A to Mini-B cable
- 3D printed or custom PCB case (optional)
- Download and install the control software for your operating system from the project's GitHub repository:
git clone https://github.com/betoule/smartiris.git
cd smartiris
pip install .- Connect the controller to your computer via a USB port using a USB A to Mini-B cable.
- Ensure that an Iris shutters is properly connected to the controller with matching channel assignments. Port "A" and "B" refers to the left and right port respectively.
- Test the status:
smartiris statusExample output for two closed and connected shutters:
{'shutter_A': 'closed', 'shutter_B': 'closed', 'busy': False}
Unconnected shutters appear as closed. Partly open shutters may appear as closed or open depending on the sensor location on the device.
The button can be used to switch the shutters on and off. They have precedence upon the software control, meaning that if a timed exposure as been programmed, pressing any of the button will interrupt the program and close or open the corresponding shutter. If needed button can be deactivated by software.
Errors of the kind:
PermissionError: [Errno 13] Permission denied: '/dev/serial/by-id/usb-FTDI_FT232R_USB_UART_AQ01L27T-if00-port
occur when you don't have access rights to the serial devices. On linux systems you need to add yourself to the dialout group:
sudo usermod -a -G dialout usernameGroup changes typically take effect after the user logs out and logs back in. To apply the change immediately without logging out, you can use
newgrp dialoutErrors of the kind:
FileNotFoundError: [Errno 2] No such file or directory: '/dev/serial/by-id/usb-FTDI_FT232R_USB_UART_AQ01L27T-if00-port0'
occur when the serial device is not at the spectified location. You need to identify the path to the device file by looking at appearing files in:
ls /dev/serial/by-id/
#plug the device
ls /dev/serial/by-id/
#Look for the new lineafter the device has been plugged. Once the device has been identified you can specify its path as:
smartiris -t /dev/serial/by-id/{actual_device_id} statusMac-OS users should look for the device appearing in:
ls /dev/tty*.*- Schematics is available in directory
schematics - Files to build a 3D case are available in
3D - Once assembled connect your computer to the arduino and flash the firmware using the arduino IDE. The code is compatible with version 1.8 of the IDE. Open the sketch
smartiris.inoand upload the sketch.
The smartiris command-line tool controls supports several commands and options to operate the shutter.
smartiris [OPTIONS] COMMAND
-t, --tty PORT
Specify the TTY port (default:""attempt to autodetect the relevant serial device).-w, --pulse-width SECONDS
Set the duration of opening/closing pulses in seconds (default:0.03).-p, --port ID
Select the shutter port (default:A).-v, --verbose
Enable debug output for communication.-r, --reset
Perform a hard reset of the device on startup. The execution of the command is slower at first call.
-
open
Open the shutter.
Example:smartiris open -
close
Close the shutter.
Example:smartiris close -
timed
Open the shutter for a specified duration.
Additional options:-d, --delay SECONDS
Delay before action (default:0.01seconds).-e, --exposure-time SECONDS
Duration to keep the shutter open (default:1.0seconds).
Example:smartiris timed -e 2.5
-
stop
Interrupt execution, leaving the shutter in its current state.
Example:smartiris stop -
status
Display the current status of the shutter driver.
Example:smartiris status -
disable_button
Disable the on-board buttons to avoid interference with remote controle -
enable_button
Re-enable the on-board buttons. They will have precedence over remote operations
- Open the shutter with a custom pulse width on port B:
smartiris -p B -w 25 open - Keep the shutter open for 3 seconds:
smartiris timed -e 3.0 - Check the shutter status with verbose output of the communication with the device:
smartiris -v status - Interrupt a long duration exposure. The shutter will remain in its current state.
smartiris timed -e 10 sleep 0.1 smartiris status smartiris stop smartiris status - Run a 1 minute calibration of the internal clock of the device for accurate timing:
smartiris calibrate -d 1
The python library provides direct access to the controler. The control logic works as follows: a short program is written to the controler specifying which pins to operate at specific timings to energize the activation coils of the shutters. The timing are specified with a resolution of 0.5μs and can extend over a duration of up to 17 minutes. The high level functions are open_shutter and close_shutter which execute a two step program (energize the coil for a given duration then release) and timed_shutter which executes a 4 step program chaining the two operations separated by a given interval. All writen program executions can be prevented by specifying exec=False then triggered latter at will by calls to start_program. The use of delayed execution avoid cummulating random delays in the USB communication and offer the best synchronisation timing between the host and the device. Here is a complete example illustrating the various functions of the library:
import smartiris
print('Connect to the device')
# If a single device is connected, there is no need to specify the device
d = smartiris.SmartIris()
print(' Query the shutter status')
print(d.status())
print('Open the port A shutter')
d.open_shutter()
print('Wait for completion')
d.wait()
print('Close port A shutter')
d.close_shutter()
print('Wait for completion')
d.wait()
print('Open for 3 seconds after a 2 seconds delay (setup only)')
d.timed_shutter(delay_sec=2, duration_sec=3)
print('Wait for completion')
d.wait()
print('re-trigger')
d.start_program()
print('Wait for completion')
d.wait()- Record the timings of the hall sensor trigger
- Handle manual operation
- Robustify the serial communication
- Implement a calibration procedure for the MCU clock enabling accurate timings
- Handle button event
- Pull-up sensor lines to make unconnected shutter consistently appear as close
- Auto-detect the device port
First release in use during the april 2025 OHP campaign
Main contributors are:
- Marc Betoule, for the firmware and the host python library
- Fabien Frerot, for the electronics and schematics
Pull requests are welcome! For major changes, please open an issue first to discuss proposed modifications.
This project is licensed under GPL V2 License - see the LICENSE.md file for details.
- Thorlabs for manufacturing quality Iris shutters
- Open-source community for valuable contributions and support