Arduino based auto alkalinity tester DIY

[karimwassef]

I would like to be able to measure alkalinity multiple times a day (as well as while I travel).

So... Combining the following parts

1 Arduino Uno (eventually a mini pro)
4 syringes
4 micro linear actuators with feedback encoders
4 one way valves
1 50ml clear cylinder
1 60RPM DC motor & mount
1 ADA TCS34725 color sensor
2 DC power supplies (12V, 5V)

I think I can make it work... For about $140

Each syringe has a dedicated liquid in/out -

Saltwater to test
Titration fluid (acid with color changing indicator)
RODI to flush
Purge fluid (suction to the bottom of the test cylinder)

The motor is to swirl the tube
The color sensor to detect the absence of red/pink

I'll play around with it but I think I should have a resolution down to 0.5dKH

I'll take pictures once the material gets here.

[TheYellowSnow]

Subscribed

[sahin]

Wow, that would be very cool.

[perkint]

Does sound interesting

Tim

[karimwassef]

Not promising it'll work. Just that I'm going to try and take you with me

The two biggest variables are the micro actuator encoder accuracy and the color sensor trigger levels.

I hope to get those in soon enough to experiment.

[TheYellowSnow]

While waiting for the parts any chance you could add part numbers?

[jimbob321]

maybe an ESP-8266 ...7/12 would work instead of a arduino, you would have wireless that way.
it can be programed with the arduino ide.
3 volt and memory could be a problem.
just a thought...

[karimwassef]

Long term, I'm going to run Raspberry Pi 2 for data. Arduino is just a good vehicle to get it up and working.

[karimwassef]

Here's the actuator with encoder

http://www.naimotion.com/PDF_folder/...ges/mm3mex.pdf

Here's the color sensor

https://www.adafruit.com/products/1334

Here's the DC motor

https://www.amazon.com/gp/aw/d/B00M1...f=ya_aw_oh_pii

[jimbob321]

i have a few of the nodemcu boards.
i haven't found a project for them yet..

[karimwassef]

If this works, I'll add a calcium tester.. That would require one more actuator though, unless I give up rinsing with RODI and choose to rinse with saltwater instead. That would reduce cost and complexity...

The Calcium titration needs two liquids instead of one. So the 5 syringes would have to be:

Saltwater
Alk titration
Ca titration #1
Ca titration #2
Export & flush

[jimbob321]

if you go with a pi take a look at public lab Spectrometer.
it might give better results than rgb color sensor.

[karimwassef]

Procedure-

FLUSH
Fill syringe SW with 50ml of new saltwater
Inject SW into test tube (10ml)
Swirl 10sec
Fill syringe X (export) with 15ml from the test tube
Inject X export into drain
Repeat 4 more times

LOAD
Fill syringe SW with 5ml of new saltwater
Inject SW into test tube (10ml)

TEST_ALK
Fill syringe T_ALK with 0.96ml of Alk titration acid/color indicator
Inject T_ALK 0.064ml
Swirl 10sec
Check color (blue = repeat above and add counter) - if no more titration, refill
Check color (yellow = stop and capture count)
---- not sure if I should purge the rest of the acid or leave it
Fill syringe X (export) with 15ml from the test tube
Inject X export into drain

FLUSH

LOAD

TEST_CA
Fill syringe T_CA1 with 0.64ml of Ca titration 1
Inject T_CA1 0.64ml
Swirl 10sec
Fill syringe T_CA2 with 1.92ml of Ca titration 2
Inject T_CA2 0.064ml
Swirl 10sec
Check color (pink = repeat above and add counter) - if no more titration, refill
Check color (blue = stop and capture count)
---- not sure if I should purge the rest or leave it
Fill syringe X (export) with 15ml from the test tube
Inject X export into drain

FLUSH

[karimwassef]

Thanks jimbob. I'll try the Arduino and RGB to see if I can get proof of concept going. Then I can refine it based on reading accuracy.

[gREEF stricken]

If you do get this working, and you considered reliable, I would buy one. I have the DIY gumption, but not the technical background.

GS

[karimwassef]

If it works, I'll publish everything including the code to run it. The mechanical implementation is trickiest for me.

Thinking about swirling a tube with an off center DC motor configuration is messy... No spill intended

[zachts]

Interesting, tagging along, no doubt inspired by those folks who have a working prototype running and have been posting about it for a while now with the intent to patent and eventually go commercial with it......

[Gorgok]

Wouldnt using a colorometer to test the alk be easier to automate than tritation? That way you just need to pump the 1ml solution and swirl. The rest will be pretty much the same, flush, load, test flush

[805reef]

following! Would be awesome if you are able to get this working.

[nuxx]

Very interesting! Subscribed

[karimwassef]

I like titration. It's crisper than color charts IMO. But who knows where this will go.

Here's the basic concept











Please excuse the sloppy tubes... It's first concept so faster is better than pretty.

It's about 6" x 6" x 15"

[karimwassef]

Inspired by laziness... And a tinkerer's desire

[formula409]

Ok I have been thinking alot about the same kind of thing mate, but mainly for a capillary electrophoresis unit :?

I was thinking of driving the plunger pumps with NEMA17 stepper motors, there is a lot of work on thingiverse where people have made these pumps for 3D printer extruders for obscure stuff like chocolate and sand

So for pumps look at this
http://www.openpump.org/

And this
http://www.thingiverse.com/thing:475841

But there are many more designs

I dare say it would be cheaper to build and give you more graduations and control over dispensing


For your auto sampler, I would put check valves facing opposite directions on the in and out line, So that incoming fluid can travel one path and the other is blocked, and on depression leaving fluid is forced through another path

[IMG][/IMG]

You probably have the dual one way sorted but I thought It might make it easy for others to get the sampling

[formula409]

Also don't froth too hard over this

http://www.chemie.unibas.ch/~hauser/...ino/index.html

[karimwassef]

Thanks formula. Yes, the check valves are blue disks in my drawing.

I'm an old school programmer, so command line is just as pretty to me and easier to debug IMO