So as some of you know, I'm colour deficient. Unfortunately some off shades appear as other colours for me. Some greens look grey or brown, some blues look purple, and some reds look pink or brown. Basically it means I need someone else to help me with water tests or I make my "best guess". There are professional kits on the market that use light intensity loss to measure the colour of the test solutions but they cost A LOT, hundreds for one kit to thousands for a set. Well, I found this a few months back: colorimeter
It's a *fairly* simple design for a colourimeter.
The basic principal is that the colour of the sample being tested will allow a varying amount of light through to change the resistance in the Csd Photocell. Now because in theory this should be a linear development (from the test sample) one should be able to extrapolate numbers above, below and in between "normal" ranges. For example, say you have a PO4 kit that only goes down to 0.5ppm and in 0.5ppm increments. If you're running a SPS reef and want to know a number below that, this should be able to tell you. Goes the other way too though, there is absolutely no need what-so-ever to get that accurate with NH3/4. Simply put, if you have a NH3/4 reading period, you have a problem
.
Now I've run into a few problems... Because the design was translated from Dutch (and I don't read/speak dutch) a lot of the info is either missing or I'm guessing at a translation from Babelfish. Also a lot of the parts have no lableing or explanation at all other than their part number making it even more tough to figure out. So I came up with this:
Basically I simplified the design, made it portable (I'm not always sitting right by a power outlet when I do water tests), and made it so one could do tests on the different coloured test solutions without needing to use a three colour LED (which has light angle problems). I also added an onboard meter so I don't need to use my multi-meter every time.
Now I may have a few problems... In my mind, the POT's should be on the circuit controlling the LED's and not the Photocells. I'm not entirely sure why but I figure the LED's intensity is what should be "tuned" as opposed to the resistance of the Csd's. Also, I may have run into the first major issue with the translation... I bought a Volt meter circuit board when I have a feeling now that it should have been for Ohms. All things considered, I guess that's why it's called a "Prototype".
Anyway, almost all of the parts needed to be shipped in from Vancouver so best case scenario, I'll be able to start playing Monday or Tuesday. Once I have the parts, I'll also buy a project box and take it into work so I can mill out the slots/holes.
As soon as I have the parts, I'll be doing up a prototype parts list.
Another thing to note... I wouldn't recommend rushing out and getting these parts lol. Let me wreak a few things first .
Now for the Prototype parts list:
1) 3 Csd Photocells
2) 1 each of Red, Green and Blue LEDs on bayonet bases with integrated resistors for 6V use.
3) Bayonet based lamp holders (mine came with a clear lense which I may end up removing)
4) 4 SPST toggle switchs
5) 4 Water proof boots for the above (make sure you match the threads!)
6) 1 10K Ohm POT
7) 1 500 Ohm POT
1 4 AA battery holder (giving you a total of 6V's... Just like the above LEDs need )
9) 1 9V battery holder (for the Meter's power supply)
10) 1 Volt meter pre-assembled circuit board (NOTE: as said above... this may change won't know until I try it lol)
11) some kind of Project Box (again, won't know until I have everything assembled)
12) 3 3/4" CPVC tee's
13) 6 3/4" CPVC cap's
14) 3 1/2" conduit compression x thread fitting (I'll try and get some pics to explain this one better)
15) To be determined, some kind of cover to keep light out of the tops of the test vials.
Unfortunately the thread on the conduit fitting isn't a standard thread SOooo I'll have to figure something out there.
Probably tomorrow, I'm going to get started on Standard Solutions for calibrating and an Excel spreadsheet made to convert whatever the Meter spits out (Volts or Ohms) to ppm. I'll probably use 4 versions (if I can make it work lol), one FW calculator and FW table and the same in SW. For the Standards I'll more than likely use Seachem products simply because I'm fairly sure their e-mail support will help me out with the calc's.
Chris
It's a *fairly* simple design for a colourimeter.
The basic principal is that the colour of the sample being tested will allow a varying amount of light through to change the resistance in the Csd Photocell. Now because in theory this should be a linear development (from the test sample) one should be able to extrapolate numbers above, below and in between "normal" ranges. For example, say you have a PO4 kit that only goes down to 0.5ppm and in 0.5ppm increments. If you're running a SPS reef and want to know a number below that, this should be able to tell you. Goes the other way too though, there is absolutely no need what-so-ever to get that accurate with NH3/4. Simply put, if you have a NH3/4 reading period, you have a problem
. Now I've run into a few problems... Because the design was translated from Dutch (and I don't read/speak dutch) a lot of the info is either missing or I'm guessing at a translation from Babelfish. Also a lot of the parts have no lableing or explanation at all other than their part number making it even more tough to figure out. So I came up with this:
Basically I simplified the design, made it portable (I'm not always sitting right by a power outlet when I do water tests), and made it so one could do tests on the different coloured test solutions without needing to use a three colour LED (which has light angle problems). I also added an onboard meter so I don't need to use my multi-meter every time.
Now I may have a few problems... In my mind, the POT's should be on the circuit controlling the LED's and not the Photocells. I'm not entirely sure why but I figure the LED's intensity is what should be "tuned" as opposed to the resistance of the Csd's. Also, I may have run into the first major issue with the translation... I bought a Volt meter circuit board when I have a feeling now that it should have been for Ohms. All things considered, I guess that's why it's called a "Prototype"
.Anyway, almost all of the parts needed to be shipped in from Vancouver so best case scenario, I'll be able to start playing Monday or Tuesday. Once I have the parts, I'll also buy a project box and take it into work so I can mill out the slots/holes.
As soon as I have the parts, I'll be doing up a prototype parts list.
Another thing to note... I wouldn't recommend rushing out and getting these parts lol. Let me wreak a few things first .
Now for the Prototype parts list:
1) 3 Csd Photocells
2) 1 each of Red, Green and Blue LEDs on bayonet bases with integrated resistors for 6V use.
3) Bayonet based lamp holders (mine came with a clear lense which I may end up removing)
4) 4 SPST toggle switchs
5) 4 Water proof boots for the above (make sure you match the threads!)
6) 1 10K Ohm POT
7) 1 500 Ohm POT
1 4 AA battery holder (giving you a total of 6V's... Just like the above LEDs need )
9) 1 9V battery holder (for the Meter's power supply)
10) 1 Volt meter pre-assembled circuit board (NOTE: as said above... this may change won't know until I try it lol)
11) some kind of Project Box (again, won't know until I have everything assembled)
12) 3 3/4" CPVC tee's
13) 6 3/4" CPVC cap's
14) 3 1/2" conduit compression x thread fitting (I'll try and get some pics to explain this one better)
15) To be determined, some kind of cover to keep light out of the tops of the test vials.
Unfortunately the thread on the conduit fitting isn't a standard thread SOooo I'll have to figure something out there.
Probably tomorrow, I'm going to get started on Standard Solutions for calibrating and an Excel spreadsheet made to convert whatever the Meter spits out (Volts or Ohms) to ppm. I'll probably use 4 versions (if I can make it work lol), one FW calculator and FW table and the same in SW. For the Standards I'll more than likely use Seachem products simply because I'm fairly sure their e-mail support will help me out with the calc's
. Chris
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