Spectroscopy

I have always been interested in the relationship betweeen light and matter. The visible effect of the interaction between photons and  electrons. By chance I discovered on Hackaday.io the RamanPi-Project. I was fascinated by the the amazing possibilities of building a DIY Raman Spectroskop. But on closer inspection it revealed a lot of problems, which weren’t easy to solve.

However, in the search for solutions, I found the the Otterly-Raman-Project by Esben Rossel. This caught my intention and I spent the last three months in building a OtterVIS LGL. Ottervis-LGL

In the picture above you see the result:

  • halogen lamp
  • Raspberry 3
  • Spectrometer OtterVIS
  • Ubuntu 16.04 connected via VNC to the raspi und via usb to the nucleo-F401RE

After fiddeling around with the software, I got following results.

The first two pictures show the recordings of two laserpointers with 405nm and 532nm respectively. These spectra were stored on the disc and used by the program to mark the x-axis in nm. The third one displays the settings for the SH- and ICG-pulses. Please revere to linear-ccd-module .

Now follows the recording of the lightsource, a halogen-lamp. The light went through a cuvette filled with water. This spectra was taken as the baseline. A following record shows the difference between baseline and lightsource-recording.

The last spectra in taken from a cuvette with a solution of crystal violet in water.

The Software is still under construction.

Have fun experimenting:linear-ccd-module .

Installing GUI on raspberry pi:
  • Download and install raspbian.
  • Update the system.
  • Run raspi-config and enable SPI.
  • Resize SPI buffer (by default it’s too small). Append the following to the line in /boot/cmdline.txt:
spidev.bufsiz=8192
  • Install gnuplot.
  • Install libgtk-3-dev
  • Install wiringPi.
  • Install libbsd (sudo apt-get install libbsd-dev)
  • Install kplot https://kristaps.bsd.lv/kplot/
    (uncomment line 9 in the Makefile | configure / make /sudo make install)
  •   otterly-raman-gui-jfs.tar (8,4 MiB, 37 hits)

  • change directory and try make
Installing the software on the nucleo
  • Please look up Esben Rossel projectpage for details.
  •   TCD1304-jfs (236,8 KiB, 37 hits)

Howto use the software

Copy the .bin-file to the F401 and connect via the usb to putty or realterm. The terminal  monitors the connection between F401 and the rpi. I think the best way to control the rpi is with VNC on the same computer. If you start a record in the Otterly-Raman-GUI you should see the same parameter on the terminal. Maybe you have to reset the F401.

 

 

 

 

Further hints on the usage
  • The spetra is saved or loaded either as [int , int] or [float , float]. You can toggle this with [Save/Load in nm]. I chose the format because it is compatible with octave.
A new Version (UART)
  • I adjusted my software adaptation.
  •   otterly-ccd-uart.tar (5,2 MiB, 24 hits)

  • It works now with the latest UART Firmware from Esben.
  • Some new features to try.
    • sliders for the x axis
    • slider for the y axis with the option of  auto resizing.
    • baseline and absorbance

New Development

I focus my interest now on Java programs which run independently of the system.

Please try https://github.com/jfsScience/jfsOtterVIS