Simple DIY Automatic Alkalinity Tester - Phase #1: testing drop count

wacky123 · Apr 28, 2021

Starting a new project for Simple DIY Automatic Alkalinity Tester for a common man with can be created and printed easily with minimum cost.
Currently starting with:
-Api KH bottle
-Speed Sensor Module - https://www.aliexpress.com/item/32986575618.html?spm=a2g0s.9042311.0.0.26c94c4dlCiga1
-Arduino Nano
-small water pump
-some tube
-3d printed model

Gtinnel · Apr 28, 2021

Very interested in following your progress on this.
It also makes me question how a company can justify charging as much as they do for an automatic tester when a hobbiest (I'm possibly incorrectly assuming you're just a hobbiest) can make their own for what will probably cost very little.

wacky123 · Apr 28, 2021

Gtinnel said:
Very interested in following your progress on this.
It also makes me question how a company can justify charging as much as they do for an automatic tester when a hobbiest (I'm possibly incorrectly assuming you're just a hobbiest) can make their own for what will probably cost very little.

i agree , feels like any thing that has reef symbol on it is marked up substantially higher

wacky123 · Apr 28, 2021

some minor upgrades, counter sensor is very week so right top down approach.
any suggestion for better counter sensor will be appreciated.

video coming soon .....

wacky123 · Apr 28, 2021

3D models : https://www.thingiverse.com/thing:4842730

elysics · Apr 29, 2021

Gtinnel said:
Very interested in following your progress on this.
It also makes me question how a company can justify charging as much as they do for an automatic tester when a hobbiest (I'm possibly incorrectly assuming you're just a hobbiest) can make their own for what will probably cost very little.

Its not all that bad, if you use the same concept as the commercial ones, material cost is around 100-200 if you get everything from china, slightly more for high quality and good looking components. And then you have assembly, profit, engineering and software development for a nice app with a cloud or interaction with a controller, which is easily the most important part for a commercial one.

Slightly optimistic about this one though, I have read about the optical approach before, might work out great.

To really be automatic it would need at least 3 more pumps though (taking water from tank, pumping water back out of the test chamber, one for pumping in rodi to rinse out the color, at least the first one needs to be an accurate one) as well as a stirrer, which can be made from a broken pc fan and some magnet fragments

Gtinnel · Apr 29, 2021

elysics said:
Its not all that bad, if you use the same concept as the commercial ones, material cost is around 100-200 if you get everything from china, slightly more for high quality and good looking components. And then you have assembly, profit, engineering and software development for a nice app with a cloud or interaction with a controller, which is easily the most important part for a commercial one.

Slightly optimistic about this one though, I have read about the optical approach before, might work out great.

To really be automatic it would need at least 3 more pumps though (taking water from tank, pumping water back out of the test chamber, one for pumping in rodi to rinse out the color, at least the first one needs to be an accurate one) as well as a stirrer, which can be made from a broken pc fan and some magnet fragments

I doubt the cost of parts would even be $100 if sourced from off brand Chinese parts. If you used all higher quality parts I do agree it could easily be over $200. You could have close to that in pumps alone. With that in mind something like the Trident may not be too overpriced at $600, but I still think something like the KH Guardian Pro at nearly $1300 is way overpriced.

elysics · Apr 29, 2021

Gtinnel said:
I doubt the cost of parts would even be $100 if sourced from off brand Chinese parts. If you used all higher quality parts I do agree it could easily be over $200. You could have close to that in pumps alone. With that in mind something like the Trident may not be too overpriced at $600, but I still think something like the KH Guardian Pro at nearly $1300 is way overpriced.

Eh, reagent pump alone is somewhere around 40+shipping straight from the factory in china, I know, I ordered one, and that's the one used in the cheapest commercial tester. Normal pumps+drivers are 10 each, and most devices use stepper motors for the other less critical pumps as well. the cheap chinese fake electronic stepper drivers for the stepper motors are another couple dollars each, water proof housing, galvanically isolated ph circuit is expensive, even with fake parts, ph probes are 20 or so even from china if you don't use bottom of the barrel quality, magnetic stirrer another 10 if you don't scavenge for parts for that, then the arduino/mainboard, tubing, a reactor vessel, fittings, it all adds up

Agree on the guardian, but maybe that can be excused by being the first of its kind afaik

blazerino · Apr 29, 2021

Gtinnel said:
I doubt the cost of parts would even be $100 if sourced from off brand Chinese parts. If you used all higher quality parts I do agree it could easily be over $200. You could have close to that in pumps alone. With that in mind something like the Trident may not be too overpriced at $600, but I still think something like the KH Guardian Pro at nearly $1300 is way overpriced.

The KH Guardian Pro is only $479 with 1 packet of reagent. For an extra $20 they sell the module that allows you to hook it up to your apex via the PH or ORP port.

wacky123 · Apr 30, 2021

Still struggling with precision with one drop, for some reason water piles on and drops in 2-3drops ... going back to drawing board, adding a pin at the outlet helps a little, maybe cone shape outlet on the out hole might limit the amount that comes out.
still trying to keep it simple for a common man .. suggestions are welcome .. posting a video.

All the parts order were around $20-30 not including the parts i already had .. no ph probe, using the color sensor checkout my other project. i have 3 idea for mixing, centripetal force by spinning vial tube(other project), magnetic stirrer - 3d printed and poc done but will require solenoid pump for drain- will post soon, last my favorite shaking the vile side to side with a servo and than flip for drain -- simplicity. .... Phase #3

Phase#2 Api KH bottle sitting on the top and squeezing mechanize to squeeze the juice out.

elysics · Apr 30, 2021

For low drop to drop variation, consider using some kind of dispensing tip, maybe just repurpose the pink ones coming from a titration test kit and cut off a bit of the tip to make the hole wider, or just the syringe itself without a tip for that matter, depending on how big you want them to be

And it's probably going to be more accurate if you can make it so the drop comes out perfectly vertical

wacky123 · May 3, 2021

Phase #3 for mixing reagent from API KH test kit, very simple approach on mixing and dumping, still need to perfect the code but the theory and concept seems to work.

phase #2 delayed, parts on in yet..

please feel to leave constructive comments.

wacky123 · May 30, 2021

I haven't forgotten about the common man still waiting of parts but the prototype is ready, drop counter is still being different with precision but will work out the kinks later with better method of counting drops.
Will be posting video soon with tests

wacky123 · May 30, 2021

1st trial ...

Borat · Dec 1, 2021

wacky123 said:
1st trial ...

How is it going with this project? Nice idea about drop counts - including water addition, avoids having to use stepper motors..

MrDarkArtz · Jun 5, 2022

I haven’t read the whole thread so this may be a useless comment, but could you not use a photo interrupter? Something like the ITR9608

wacky123 · Jul 25, 2022

Borat said:
How is it going with this project? Nice idea about drop counts - including water addition, avoids having to use stepper motors..

The project has been on pause for a while, i had a kid and than my tank crashed but not the tank was been recovering nicly and kid is grow fast so might start again on the project if there is still interest.
Phase#2 has been quite challenging as the linear solenoids to push and squeeze the bottle has not been strong enough so resorted to much stronger 20N solenoid to do the job, will post results soon.
Still trying to keep is under $50 and simple, with less moving parts and less maintenance work.

wacky123 · Jul 25, 2022

MrDarkArtz said:
I haven’t read the whole thread so this may be a useless comment, but could you not use a photo interrupter? Something like the ITR9608

Using a speed senor to count the drops, had to cut n repurpose it but its not accurate, always seems to miss drops, so resorted to time based instead, start time for the pump on first drop and shut pump off after a certain time to get exactly 5ml.