Backyard Aquaponics
A place to discuss aquaponics

I would really like to get into some of this stuff..but I dont really have any reason to at the moment..all in good time I guess

The advantage of learning something before you need it, it that when you need it you already know it

That's why I doing it

so..I read the "Getting Started" Picaxe manual last night.. dont think I could really start getting to know what I am doing until I actually buy a chip.. but I had a question for you BW.. I have seen people monitor things like Ph, ammonia, nitrite etc but couldnt find these sensors in the picaxe online store or in my most likely misguided google searches..

are they availiable?

Firstly, I dont really know, But I'll answer anyway

I think those things exist, but you cant just leave them in the water. I think you get oxidation on the probes, bio slime, etc etc that means you have to take the probes out, wash them, then calibrate them in a "known strength solution" ie dip them in to some bottle marked "pH7.5" then reset the device to 7.5, then test your water. I dont think you can just leave them running. At least not for the kind of price you might want to pay.

I'm guessing you could do it with something like one of the devices used in CSI labs on tv, but I'm guessing it would also be cheaper to just buy an island with lots of fish and vegetables growing wild.

But...

On the up side, after answering this without really knowing the answer, I'm sure there are plenty of people here who do actually know the answer


Also..when searching, I recommend you use the word "probe". It's the kind of word people who make such devices like to use, because it's a very futuristic sounding thing to own.

try dissolved oxygen probe, pH probe, ammonia probe.

Basically just do whatever searches you did, but add the word probe*.



*Avoid searching for UFO + probe.

I don't know about pre-made sensors, but you could build one with a probe + analog/digital convertor to measure the voltage with a little glue circuitry.

documentation is all online http://www.picaxe.com/Getting-Started/PICAXE-Manuals/

I found this the other day and thought you might like it.

Its an educational version of picaxe that allows you to bolt together bits without soldering. This way you can learn (and make) picaxe stuff without having to learn and trust your soldering skills. (although I have to say soldering wasn't as hard to learn as I thought you need to get some advice on what size solder and what soldering iron to buy from your electronics parts store)

So you buy the base that has copper paths to a half a dozen points around the board. These have small bolt holes. Then you buy the sensors or motors, switches, keypads or whatever you need that also come in the form of a pre-made circuit board with holes that match to the main board.

You bolt on a temperature sensor module to pin 2. And bolt on motor module to pin 4, and you can take a temperature reading in your glass house and open a vent if it's too hot.

That would take a few lines of code (perhaps 10) and the three boards.

as an example of cost, there is a starter pack with 15 assorted boards... temperature, pressure switch etc that comes with the mother board and 15 bolt on little boards for around $80. http://www.techsupplies.co.uk/epages/St ... cts/BOT115

This stuff is new so there are parts that they dont do yet. But they will have a 8 pin chip version and you can buy each of the little boards separately. there are no prices for the stuff that doesn't exist yet, but I suspect my example of a 8 pin motherboard, a temperature sensor, and a motor controller would cost around $30 when it does come out.

Doing it with solder would cost around a third of that.

I would suggest the Arduino if people were going to go in the direction of chips with bootloaders. Otherwise, I would heartily suggest learning to program the microcontrollers themselves. The Atmel AVR (that the arduino is based on) is very good, the Microchip PIC is very good as well.

One benefit of learning to work directly with these chips is that you get access to all of the goodies. One thing that the PIC has is the Charge Time Measurement Unit which has a lot of great applications for our purposes. I'm in the process of building a few of the sensors suggested in this application note:

http://ww1.microchip.com/downloads/en/AppNotes/CTMU%2001375a.pdf

The programmers for the chips (ICSP or in-circuit serial programmer) are often very easy to build or cheap to purchase, and all of the software to program the chips is freely available.

It's important to remember that these chips will do exactly what you tell them to, so program testing is important. I'm happy to help if people have code trouble. Unless we have a software engineer about on the boards, in which case I defer to them!

Cheers
ks