B&W-tech Spectrometer & 473 module: Setup+Mods+Info

[Mosc007]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

According to the science surplus site using 600 grating it can do 365 - 1100

 

[paul1598419]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

Mosc007, you should also add a pause funtion so you can freeze a spectrum taken. Also being able to change the integration time would be great. I have my USB2000 set to 50 ms, but can change that anytime. This software has a very long integration time. And it samples only about every couple of seconds. That is terrible. I have found no way to pause the spectrum taken, so as it samples every couple of seconds it changes too.

I don't know about the Science Surplus software. Seems a few member use that and are happy with it. I know of two other members who have OEM software besides myself and they like theirs as well. I haven't been able to compare the two, so I can't speak from experience, but the OEM software is very comprehensive and allows me to do many other things than take a laser spectrum. It is also very interactive and allows me to change settings on the fly.

 

[Atomicrox]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

Edit: this isn't correct! Read more here: http://laserpointerforums.com/f42/b...trometer-mods-info-101467-13.html#post1497669


If the built in grating is really 1800 ln/mm I don't see how it could go any higher than 555nm, after all:
d*sin(angle) = wavelength

The specs on the science surplus website make no sense at all:
1800 l/mm 365 - 600 nm 1 nm

To get the whole visible range we'd need at most around 1200 ln/mm.

 

[Mosc007]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

Mosc007, you should also add a pause funtion so you can freeze a spectrum taken. Also being able to change the integration time would be great. I have my USB2000 set to 50 ms, but can change that anytime. This software has a very long integration time. And it samples only about every couple of seconds. That is terrible. I have found no way to pause the spectrum taken, so as it samples every couple of seconds it changes too.

I don't know about the Science Surplus software. Seems a few member use that and are happy with it. I know of two other members who have OEM software besides myself and they like theirs as well. I haven't been able to compare the two, so I can't speak from experience, but the OEM software is very comprehensive and allows me to do many other things than take a laser spectrum. It is also very interactive and allows me to change settings on the fly.

Pause would be great. Currently i have start and stop. But pause buttion easier. Saves struggling to get a screen capture between updates. Its using 50ms integration by default but easily changed. Because these are serial comms there is a limit on how fasf it can update. I set it to read once a second. I am also using ASCII mode because i dont know the compression algo for binary mode. Its not in the PDF file. That would speed up data transfed a lot. It is using 112 kb in high speed mode.

Many things to do with it. All suggestions are most welcome.

 

[Cyparagon]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

Can these spectrometers be adjusted to work further into the NIR region, lets say above 808 nm?

Mine goes down to ~910nm (with an upgraded grating). 1064+ would be attainable with yet a different grating.

If the built in grating is really 1800 ln/mm I don't see how it could go any higher than 555nm, after all:
d*sin(angle) = wavelength

That doesn't follow. Please show your work.

To get the whole visible range we'd need at most around 1200 ln/mm.

These were designed for a specific range. Unfortunately, you cannot fully re-direct the span without introducing astigmatism into the focus. Some of the CCD pixels need to be thrown away on un-readable UV if you increase the span. You're not accounting for this in your math.

Got a copy of it you can share?

I'll see what I can dig up this weekend. There's also an applet thing that enters the calibration constants I'll need to find - you can't enter them with the regular user interface

 

[diachi]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

That doesn't follow. Please show your work.


I'll see what I can dig up this weekend. There's also an applet thing that enters the calibration constants I'll need to find - you can't enter them with the regular user interface

Ok, so I'm not the only one that didn't follow there....

That'd be excellent if you can! Would appreciate it greatly.

There's talk of chipping in and buying the BWSpec software, which I'd be up for if there's enough people interested in it to lower the cost enough.

 

[Mosc007]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

Ok, so I'm not the only one that didn't follow there....

That'd be excellent if you can! Would appreciate it greatly.

There's talk of chipping in and buying the BWSpec software, which I'd be up for if there's enough people interested in it to lower the cost enough.

I wouldn't mind chipping for a copy of the original software.

 

[paul1598419]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

I'm in for the BWSpec. I think Alaskan would be too.

 

[diachi]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

New development here on my end... Just checking I can share what I have before I share it. I'm sure it'll be fine, especially with some information exchange, just don't want to take the liberty. Will keep you all posted. Don't go buying any software yet!

Lazerman121, if you're reading this, thanks!

 

[Atomicrox]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

That doesn't follow. Please show your work.

Assuming the formula is correct
d*sin(angle) = wavelength

sin(angle) can be at most 1 when angle = pi/2, so maximum wavelength equals the distance between slits

1800 ln/mm = 0,0018 ln/nm
d = 1/0,0018nm = 555nm

This does agree with experimental results I've had with a 1000ln/mm grating.
What did I miss?

 

[paul1598419]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

Assuming the formula is correct
d*sin(angle) = wavelength

sin(angle) can be at most 1 when angle = pi/2, so maximum wavelength equals the distance between slits

1800 ln/mm = 0,0018 ln/nm
d = 1/0,0018nm = 555nm

This does agree with experimental results I've had with a 1000ln/mm grating.
What did I miss?

What you are missing is you need to manipulate the formula to get the angle. Then taking the acrtan of of the angle you get the hypotenuse of the right triangle. Solving for the other legs gives you the position of the first order principal maxima for that particular wavelength. If I worded this incorrectly it is because I was up late and just woke up. But, I believe this is correct.

 

[Atomicrox]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

I don't think that's it, no matter what the distances or the angle are, the sine can't be more than 1.

 

[paul1598419]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

As long as you stick to the first order principal maxima, it never will be. It is only when you use the third order maxima that you run into a problem like that.

 

[Mosc007]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

I have done some work on my software for use with this Spectrometer.


The scale is in Pixel Number for the moment. It's roughly 400-650 nm

When I get the calibration software working I will update it. I have been doing some research on polynomial formula to create a calibration curve. Pretty much what the existing spectro software uses. If I cant find the formula to solve the equation you may need to use Excel to solve it then put the variables into the software.

You can set the integration time from 50-500ms but i found it was not really useful. The CCD in these spectro's is very noisy. The default from the device is 50 ms which seems to be fine.

I have included a Dark Frame option to remove the majority of the noise.

To create a dark frame. Start capturing as normal except block all light input to the spectrometer. Once you have a capture on the screen Pause the data. From the command menu save this frame as a Dark frame.

Operation of the software should be pretty straight forward. It will scan for active Com ports when you run it. Select the com port you are using. I was using Windows 7 with a USB to Serial and it worked fine.

Once the com port is selected click connect. It will send the parameters to the device and after it's been acknowledged Ready will be shown in the status bar down the bottom. Simply click Start to start capturing. You can pause the data flow at any time.

Please turn on the Spectrometer before running this software. Wait a few seconds for it to power up.

NOTE.

This is written in VB6 which is very compatible with all versions of windows. Very old software but it never fails to run on new versions of windows. Sometimes in Windows 10 you may need to run it as Administrator though.

It does use one OCX file which you will need to install if it's not already on your system. You will need Mscomm32.ocx. You can easily find this on Google. If you download the OCX file and not the install package you will need to register it manually.

If there are issues installing mscomm32 I can create a full install program for the spectrometer software. VB does support it but it's not very pretty to look at...

Spectrometer Download Link

If you have any questions please ask.

 

[paul1598419]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

@Mosc007

The equation is: y=It+C1X+C2X^2+C3X^3. It= pixel #1. The other three make up the curve. C1, C2, and C3. Not sure if this is what you are looking for. If not, let me know.

 

[Mosc007]

Re: B&Wtech 473nm unit / Spectrometer Mods & Info

@Mosc007

The equation is: y=It+C1X+C2X^2+C3X^3. It= pixel #1. The other three make up the curve. C1, C2, and C3. Not sure if this is what you are looking for. If not, let me know.

Thanks Paul, I know that Equation. But how do I solve C1, C2, C3 ?