NPK sensor

Hello guys,
can anyone tell me how to make my own NPK sensor. i go through the internet and found many kits but they all use big kit including some testing capsules, etc. it is very lengthy process and have to be done manually.
my aim is to make a stand alone device that can do all these stuff itself just with some inbuilt circuitry. I want to know what electronic and chemical combination helps me to make a stand alone device that can used to measure the NPK values and fed it into a micro-controller.

This has been covered before here I think - I believe the consensus is there is not such thing as
a small cheap NPK sensor, you need to do chemistry to get decent results.

Thanks for your reply, Sir.. i understand the 'chemistry' point and i agree with that. but what i am thinking that can we make stand alone device that can do automatically, just put your device in soil and everything done and got our reading on display device. because i have to do the chemical process manually.
and according to my aim, i don't have to go to every place for just measuring the NPK values of soil, i want every reading on my display.

Well start by describing the chemical process and start trying to figure out how to automate it. It isn't enough just to want a thing to exist. Try making one. It isn't going to be easy. It definitely won't be cheap.

I wonder if those things even exist - at any price. As these elements can appear in various different mineral forms, it's not easy to detect the NPK amounts. N comes in nitrate, nitrite, urea, ammonium, and probably more forms including protein. P in the form of phosphates, and all kinds of chemical compounds found in plant matter. K is the easy one, that's just the element.
Mass spectroscopy comes to mind to get to the actual amounts of the different elements present, but in that case you must make sure you do not get any rock minerals (sand) in your samples, as the K in there is not accessible to the plants. Good luck automating this.
Usually if something that's potentially very useful doesn't exist, there's a good reason for that :slight_smile:

Mass spec wouldn't break them all down. Not really what you'd want here. You need ICP here.

That should do the job indeed. It's way too long ago since I've worked with such equipment to remember all the details :slight_smile:

It must be able to automate this, after all there's a mass spectrometer (don't know whether it's the ICS type) on board of one of the Mars rovers.

It's really cool how far they've come isn't it? When I first started with mass spec they were huge magnetic sectors. Quadrupole specs were the new fangled tech. Now we can build an ion trap that could fit in the palm of your hand.

Indeed, quite amazing.
But still not something that's cheap and easy enough to have crawl around your garden analysing your soil. That Mars rover, even without the launch cost, is pretty much out of my budget :slight_smile:

I have go through further reading on this topic, and i found a tiny device "Parrot flower power" made by Parrot. this device is able to perform NPK sensing. u can have a look to that, please refer below mentioned link:

The web page of this device mentions generic fertiliser, not NPK.

Ok sir, i agreed to your point. so, what "elements" should i consider to determine the fertility of soil? and how?

because, in NPK, i know that i have to measure mass/quantity of N,P,K but in generic fertilizer, i don't know.

i will read about it again then back to forum,if i need help.
Thanks sir.

The NPK values are a measure for the amount and type of generic fertiliser.

I'm afraid you have to start looking up what NPK stands for, and get a real understanding of what it means for fertilisers.

okkk sir.... i am working on it...

roycorcaigh:
look at www.aptisens.com

Seems you're connected to that business.
Three the same posts with only a link to that site is a bit suspicious.

This is a DIY Arduino forum.
You could ofcourse explain how it is done, and offer the actual sensors, with datasheets.
Leo..