There's been a bit of a hiatus from the spectrometer controller project as I've been busy with other things and was also on vacation with friends and family. There isn't much left to do.
No need. That answered my question. Thanks.
I can either make the new PCB behave as in the manual, or
like it actually is. Maybe I'll just store 32-bit floats.
Hi Chloderic,
Whenever you get time, would you mind doing a coefficient query command (?C) on one of your units and post the result?
I can't seem to set the coefficients on my stock unit. It accepts the command, but noting changes when I check the results.
There are other things as well that...
Hi chloderic,
I assume this reply was meant for the other thread.
Yes, I'm aware of that.
According to the manual 2048 pixels are transmitted from the serial port, and I'm getting 2049 in binary mode after decompression.
It's not a big deal; the number of pixels transmitted can be made variable...
I've been quite busy but I found little more time to work on this project.
I noticed that I'm consistently getting 2049 decompressed 16 bit words from the stock spectrometers rather than the 2048
stated in the command set manual. Can anyone confirm this?
With my replacement PCB, then number of...
Hi chloderic,
I remember trying that command and it didn't seem to work on my stock spectrometer.
I'll look into it. I could certainly add it to the new PCB.
Hi kecked,
Thanks.
I wrote a program in C that pipes data to gnuplot. Nothing fancy.
I just execute the program in a terminal and a spectrum pops up in gnuplot.
It also writes data to a file for manipulation in Octave.
This is all in Linux.
Here are pixels 1 - 300 with dark frame subtraction.
Reduced fixed pattern noise.
Not seen are a couple of hot pixels between 300 and 2048 which are of course nulled by DFS.
On the stock spectrometer, it appears that the optical black pixels are scanned, and as a result, several pixels are lost...
Hi chloderic,
Thanks.
Would you rather go by Bernd?
I realize I should have used dark frame subtraction for the noise test.
I'm mostly seeing pixel variation. In the future, I might install a peltier cooler to bring the dark current noise down.
Hi,
I made an integrating sphere out of some cheap aluminum cake pans and a collimating lens from a bar code scanner.
This definitely improved the results. Tweaking the bench and finding a better cable is the only way I'm going to further improve it at this point.
Noise is about the same as the...
Hi all,
The slits look ok. They might be slightly off. It's hard to tell.
I think my makeshift diffuser isn't good enough and I'm getting a top hat to doughnut profile coming out of the fiber in some cases.
A gaussian profile entering the slit would be ideal.
An integrating sphere or cosine...
I've got six older Ocean Optics spectrometers and their spectral readouts definitely look much better.
They have narrower slits as well.
For what paid I for the B&Ws , I'm not disappointed, and I should be able to tweak them in, hopefully.
They're fairly compact with my PCB.