Hi all, new to the forum this is my first post. I, too, have an interest in a DIY NIR spectrophotometer. I've been doing a fair bit of homework on the properties of diffraction gratings and overall spectrometer design. My thoughts are not to do FT-NIR, but rather, just a NIR spectrometer that is as low-budget as possible (MODS: If I need to start my own thread, just let me know). My basic ideas include the following points: 1) Eliminate optics by using either (A) a Rowland Circle configuration with a constant focal length equal to the diameter of the Rowland circle as is described here: http://www.physics.arizona.edu/~haar/ADV_LAB/ROWLAND.pdf, or else use (B) a holographic abberation-corrected grating designed for a constant-deviation monochromater. 2) Use a relatively inexpensive InGaAs photodiode for the detector such as can be found here: http://www.thorlabs.us/newgrouppage9.cfm?objectgroup_id=285
3) If I am doing 1(A) above, then perhaps I can simply curve some CD-ROM material by sandwiching it between two pieces of some 6" ABS pipe with a window cut out of the inner (concave) piece to expose the grating. 4) Use as simple a configuration as possible of toothed pulleys, a timing belt, a tensioner, and a stepper motor to control the rotation of the moving parts. 5) Use an Arduino to handle the A/D conversion of the output of the photodiode, and also to control the stepper motor. Am I on the right path here? Does anybody see any potential fatal flaws in my fundamental plan?
