I have recently completed a spectrometer that covers 400 to 900 nm (visible and a bit beyond). If anyone is interested I can gve a guide to how it is constructed.
Attached is a photo of the (almost) finished device showing the spectrum of a didymium filter (used for wavelength calibration). For scale the display is 4x5 cm.
Why is the "attach file" not coming up?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
The main part of the device is the diode array sensor which is a TSL1402 (256 pixel) which is surprisingly cheap and appears to have sufficient accuray to do the job (I got mine from Digikey).
The processor is a PIC16f1788 as I needed quite a bit of RAM and as a bonus it has a 12-bit ADC.
The diffraction grating is a plastic holograhic one 1000 lines (which are strangely better than expensive ruled glass ones for diode arrays). The light source is a torch bulb and the two lenses are 3cm focal length (made of plastic glass would have been better, but size and price considerations won).
The display is one of those 240x320 TFT displays that can be picked up cheaply, but sucks current and is slow.
Attached is a labelled view with the top removed. It's difficult to see everything due to the black felt use to stop stray light. Notice the liberal use of epoxy.
I'm now fairly happy with the code. So I will post it. It could maybe do with some tidying.
I will eventually get round to the circuit diagram, but the comments in the code give away most of the connections. Due to the voltage drop on the micro pins transistor switches have been used (npn where possible but some by necessity are pnp). The transistors are on the bulb (big current so ZTX 651) on the TTF backlight (yes it has to be off when recording a spectrum) ZTX 450. The diode array, SD card and TTF logic are also switched but just standard types are required (BC550, BC560 or equivalent). The base resistors are all 150 ohms.
The display actually claims to have an ILI9341 controller, but the ILI 9340 code works just fine.
I have recently completed a spectrometer that covers 400 to 900 nm (visible and a bit beyond). If anyone is interested I can gve a guide to how it is constructed.
Attached is a photo of the (almost) finished device showing the spectrum of a didymium filter (used for wavelength calibration). For scale the display is 4x5 cm.
Why is the "attach file" not coming up?
I've now managed to do the attacment.
Very good!!! If we had a Great Cow BASIC sponsor - you would get the prize for project of the month!!!!
Impressive.
Looks Great! I'm impressed. Great Cow is an enabler. So many projects, so little time.
The main part of the device is the diode array sensor which is a TSL1402 (256 pixel) which is surprisingly cheap and appears to have sufficient accuray to do the job (I got mine from Digikey).
The processor is a PIC16f1788 as I needed quite a bit of RAM and as a bonus it has a 12-bit ADC.
The diffraction grating is a plastic holograhic one 1000 lines (which are strangely better than expensive ruled glass ones for diode arrays). The light source is a torch bulb and the two lenses are 3cm focal length (made of plastic glass would have been better, but size and price considerations won).
The display is one of those 240x320 TFT displays that can be picked up cheaply, but sucks current and is slow.
Attached is a labelled view with the top removed. It's difficult to see everything due to the black felt use to stop stray light. Notice the liberal use of epoxy.
We used spectrophotometer at work for determining ICUMSA "color" of sugar solutions. Much bigger machine than yours.
I'm now fairly happy with the code. So I will post it. It could maybe do with some tidying.
I will eventually get round to the circuit diagram, but the comments in the code give away most of the connections. Due to the voltage drop on the micro pins transistor switches have been used (npn where possible but some by necessity are pnp). The transistors are on the bulb (big current so ZTX 651) on the TTF backlight (yes it has to be off when recording a spectrum) ZTX 450. The diode array, SD card and TTF logic are also switched but just standard types are required (BC550, BC560 or equivalent). The base resistors are all 150 ohms.
The display actually claims to have an ILI9341 controller, but the ILI 9340 code works just fine.
Last edit: David Stephenson 2016-08-31