attaching i2c colorimeter Adafruit AS7341

[david@rainess.com]

https://docs.circuitpython.org/projects/...en/latest/

Would love to have this implementation as a sensor for the program. 
the main purpose for me would be to replace the HANNA colorimeter test "eggs" .  I can think of 3D printing  some device similar to the Hanna "egg" and manually fill the reagents as usual with Hannna test kits .  But to have it all in the software, keep records of the measurements, charts etc. 
this can measure the light spectrum as well . though I dont know how long the i2c cable can be for that purpose .

How difficult this can be for you Rob, I wonder ?

[zfreak_1125]

https://docs.circuitpython.org/projects/...en/latest/

Would love to have this implementation as a sensor for the program. 
the main purpose for me would be to replace the HANNA colorimeter test "eggs" .  I can think of 3D printing  some device similar to the Hanna "egg" and manually fill the reagents as usual with Hannna test kits .  But to have it all in the software, keep records of the measurements, charts etc. 
this can measure the light spectrum as well . though I dont know how long the i2c cable can be for that purpose .

How difficult this can be for you Rob, I wonder ?

The problem I see with adding something like this is what/how do you correlate the values provided by the colorimeter to actual measurements of specific items (phosphate, calcium, alkalinity, etc).

If you're trying to use Hanna's reagents, you would need to know exactly what color the reagent mixed with water sample will turn and what reading the colorimeter is providing in order to correlate the two and I haven't checked, but I'm going to guess that Hanna isn't widely advertising that information about their checkers otherwise they'd be getting copied by everyone.

I would love to be able to do the same thing cause I hate comparing colors on the test kits, but I think this might be a lot more work to implement than what it seems...defer to Rob on this part.

[Rob F]

I'm sorry for taking so long to reply, I had to go on an emergency trip.

Getting that sensor to work wouldn't be too difficult but as zfreak_1125 mentioned trying to translate the data would take some work and yeah something would need to be done with the I2C.

Making a universal test meter is something I really want to do as I'm constantly asked about all kinds of parameters, this would an awesome addition and profitable. It would be the same idea as a ReefBot, simply use any reagents and program using the color charts that come with. My problem is time, I'm split between the app or something like this. I know time spent on the app is always good but ROI is much slower than something like this would be but in the end this could all be wasted time. Well every time I get thinking about this I'm closer to pulling the trigger, I think I will get some parts so I can get a better idea of what I'm getting myself into. Give me a couple weeks, I have some test kits and a tank so lets see if I can do one parameter.

[gandalf]

meanwhile, i'm making a kH automated tester, fully integrated with robotank.
it's a standalone product that will connect to robotank with an i2c cable or something similiar, then you can trigger (and manage) the kh device from robotank or directly from the LCD screen on the device itself.

[Rob F]

That sounds pretty cool, you'll have to create a thread with some details when you get it working, be careful with the I2C though, it can cause reliability issues.

[gandalf]

That sounds pretty cool, you'll have to create a thread with some details when you get it working, be careful with the I2C though, it can cause reliability issues.

yes, i'll open as soon as i have a working standalone version.
I2C is cool because it just use 2 cables , other method i've found need a defined topology and are not "plug & play".

I'll use I2C only to send command and receive data, nothing more, all the operation are inside the device (an Arduino Uno or a Nano or even a Pi, still making some test...)

Currenly, i'll struggling in print a dosing pump for NEMA17, i have some issues with the tubing...

[Rob F]

Yeah I2C is great and easy to work with but it was never designed to work off a PCB. This is the last piece I need to address for the controller, I want to change the external pH circuit so it sends data over a serial line instead plus make a small adapter of some kind so other external I2C devices such as your kH tester can connect easier.

[gandalf]

ethernet.... or wifi, Raspberry side is Easy, a Little bit harder if you have an Arduino/esp32/nodemcu on the other side as there isn't any network interface

[Rob F]

Yeah it's not easy, I2C works so well because of the addressing, my serial idea for pH has issues which is why I haven't done it yet. The best is CanBus, it's also address based and error proof built in the chips, some MCU have it built in, I believe Apex uses this. I have some for testing but haven't done anything with them yet.

[gandalf]

with canbus you can use one cable directly from the master to the slave without daisy chain or similiar? as i'm making a kh tester , what do you prefere? ethernet/wifi or canbus? i like the idea to plug and use without the needs to create chains or using one pin for each device (like with UART)

[Rob F]

I'm just writing up a message on your kH thread, we'll discuss it there. This is something I really need to address so maybe can come up with a solution.