A Python interface for Ocean Optics spectrometers designed to proved the functions of a Spectronic 20 spectrophotometer.
The goal of this project was to replace the old Spec 20s in our teaching laboratories with equivalent functionality in modern equipment. Choices of hardware and software were driven largely by familiarity. The choice of the Raspberry Pi was to make an effectively disposable computer. I picked Python 3.x (the older branch works on Python 2.7 also) for simplicity in migrating to different hardware. What I created here is a simple frontend for the spectrometer suitable for use by relatively untrained undergraduate students.
The project was written to support undergraduate laboratories, so really this repository is for people looking for a frontend
to run their spectrometer. However, the functionality of the project can readily be expanded to take advantage of the
spectrometer features. This code takes care of collecting the spectra, everything else is just manipulations in code. Simple changes in the code shift the interface from having lots of things chosen for you to needing to make lots of choices.
There is a def in the code for saving spectra. To make it accessible, you would just need to uncomment three lines in the GUI section to make a 'Save' Button visible.
I wrote this on a Raspberry Pi 3b+. The current version was updated on Python 3.9 and 3.11. Raspbian OS Bullseye was used for testing. The newer (in 2024) Bookworm OS also works but is slow on a 3b+.
For Windows or Mac you will need to make small changes to the code to deal with OS peculiarities. You will need to possess an Ocean Optics spectrometer. The LED requires building a small circuit to allow pulse width modulation of the LED for brightness control. The schematic is below. I built this on a Pi-topPROTO board which made it even easier.
extra Windows requirement:
Visual C++ Build Tools is required before installing Python-Seabreeze
See the documentation at the python-seabreeze documents
pip3 install seabreeze(https://github.com/ap--/python-seabreeze or the Conda forge)- run the seabreeze setup script
seabreeze_os_setupto add the udev rules pip3 install numpypip3 install matplotlib- (May 2024) may need to also get
sudo apt-get install python3-pil.imagetkto address an import error from matplotlib - pigpio {already part of Raspbian} (for Raspberry Pi control of the LED)
- only one python file to get ¯\(ツ)/¯
- on Raspberry Pi remember to start the PWM daemon
sudo pigpiod. Or permanently enable it withsudo systemctl enable pigpiod sudo chmod +x run_hiddento make the bash script executable. A batch file would substitute the bash script on Windows.
- a USB connected Ocean Optics spectrometer
- a PWM circuit and LED. The easiest way to do this would be on a Raspberry Pi since it has PWM pins ready to use. Other prototyping platfoms (Arduino, etc.) could be adapted easily. From a 'standard' PC, a PWM circuit can be attached by USB (Yocto, etc.). An acceptable LED for "white light" illumination can cost as little as $2.00.
| Manufacturer | Spectrometer | Works ? |
|---|---|---|
| Ocean Insight | HR 4000 | yes |
| Ocean Insight | HR 2000 plus | yes |
| Ocean Insight | USB 2000 | yes |
| Ocean Insight | USB 4000 | firmware issue? |
| Spectrometer | cseabreeze | pyseabreeze |
|---|---|---|
| HR2000 | x | x |
| HR2000PLUS | x | x |
| HR4000 | x | x |
| JAZ | x | x |
| MAYA2000 | x | x |
| MAYA2000PRO | x | x |
| MAYALSL | x | x |
| NIRQUEST256 | x | x |
| NIRQUEST512 | x | x |
| QE65000 | x | x |
| QE-PRO | x | x |
| STS | x | x |
| TORUS | x | x |
| USB2000 | x | x |
| USB2000PLUS | x | x |
| USB4000 | x | x |
| USB650 | no | no |
| SPARK | x | x |
I don't write in Python for a living, nor particularly do a lot of programming. And it shows in the code. This is
also a work in progress.
If you wish to contribute please contact me.
MIT License. This project relies on Python-Seabreeze which uses the MIT License.