Backyard Aquaponics
A place to discuss aquaponics

Hi Guys,
I'm looking for a partner to help me develop some cheap PLC like electronic devices to turn on and off pumps, check temperature, check power consumption of pumps to ensure they are running, and running under proper conditions. etc etc

I am a employed as a software engineer, and whilst I have the knowhow from a Robotics Mechatronics - computer science software engineering degree, I don't have the will or time to design circuit boards and get them made.

If anybody has any experience with Micro controllers such as an AVR and knows anything of CAN and wants to maybe make a buck or just their lives easier, I'd like to hear from you.

Cheers,

KudaPucat
_________________________
The Pale Horse Rides Again

Hi KP.

I'm developing controls as we speak using a microcontroller. I'm using a Microchip PIC18 series processor. I will also be designing the board. Here are some of the functions I'm implementing:
1. Redundant pump contols.
2. Level alarms for all tanks.
3. Water Temp monitoring for Fish tank.
4. Solar water heater control and backup electric heater.
5. Inground water cooling. (I'm in florida and the summers are long and VERY hot).
6. GB cycle monitoring and control.
7. Data logging to PC.
8. Auto fish feeder

I only wish there were an inexpensive source for water chemistry sensors This unfortunately is not part of the plan.

I am mostly retired and had a long career in controls/software but it's been over 10 years since I've written a 'C' function

I just ordered the microcontroller and no doubt it will take some time to get things up and running. My system isn't even built but this will be almost a full time thing for me so hopefully it will come together quickly. I'd love to hear ideas from anyone and I'd be happy to work with you if you're interested.

This is a commercial venture for me but I'm willing to share with anyone that's interested. The commercial aspect is for those that aren't handy and need to take it out of the box and run it. I'm designing a small system that everyone could use without giving up their backyard. I'm only doing the FOR profit to support my goal.

My goal is to TEACH others how to feed themselves. We have a huge population of Hispanics in my area. Many are from poor countries and I believe AP could make a difference in their lives. I'm hoping that I can reach out to those around me, educate them and have them take the knowledge back to their relatives.

KP,
I'm currently building a AP controller based on PICAXE micro controller (cheap!).
At this stage it will only,
1) Turn pumps on/off
2) Check and alarm on low water levels
3) Turn on backup air pump if mains fails.
But the possibilities are endless !

However, like you, I don't have the will/time to mess around designing PCB's.
I think, I will stick to a one off, with some improvised wiring !

Hello KP

I had a fiddle with some PIXAXE (simulation) a while back. See this thread. There is a simple program in there for pump control timing, some logging and stuff. I am also a software eng, and prog PLCs for a living. There is also something I wrote in that thread on using one input (sump high) and two outputs for a sump and circ pump combo which seams reasonably robust. I think a level switch is going to be much cheaper that a CT or whatever you would need for "check power consumption of pumps to ensure they are running". eg. One switch tells you if water is going in to sump, and if water is going out of sump.
Scottt, I still think even is you have a controller the best "turn on backup air pump if mains fails" technique is a single relay (240VAC coil relay with normally closed contact. When power is on the contact is held open, when power goes off contact closes running battery powered air pump or whatever)

Hi,

I did mine with AVR controllers and boards from Dontronics.

http://www.backyardaquaponics.com/forum ... php?t=2197

gg

I'm looking for some1 to help me with a turnkey solution for the technologically challenged AP ppl (also has a commercial use and home automation use)
AVR solution was nice, but too big.
I want small epoxy blob black boxes.

I'm very new to aquaponics, (that's the disclaimer) but has anyone tried using sprinkler valves and timers? The first concern I would have would be the waste in the water fouling the valves. But they would definitely be affordable. At least in comparison to the electric actuated ball valves that I would LOVE to be able to afford.

The problem with regular irrigation solenoids is that they tend only to operate when under a specific amount of pressure. Gravity feed or even pumped water does not have this pressure to open the valves.

I have tried converting them to zero-pressure but you compromise flow rates. And yes, on the subject of waste, these valves are essentially just a rubber diaphragm on top of an opening. Any blockage would cause it to leak.

As tim said, those standard irrigation values need 8psi to open.
the better option would be acutators opening and closing a plug.

Sprinkler valves are 'piloted'

Ignore the non standard port on the bottom, just imagine it's sealed.

that means that the solenoid (featured top right) does not act on the valve directly, but to save power and size, instead acts on a pilot stream.

By leaking water past the seal, the pressure on one side is reduced, allowing the spring to open the valve, the more the valve opens, the less hte differential pressure and the harder it opens.

This is great cos it opens the valve 'softly' or slowly, greatly reducing pipe hammer.
simillarly, when the solenoid closes, pressure builds up in the top section and forces the valve to close slowly.

The reason these aren't so crash hot for AP is that they REQUIRE pressure to activate them.

A lot of AP is gravity fed and just wont open the valve.
The rest is pump driven, which is low pressure*Flow = low power or low flow*high pressure = low power, compared to mains that is.

There is a hack I dreamt up, which involves opening the valve and drilling out the pilot hole, also shortening the spring. This works because it reduces the power required to open the valve, and speeds up the open by having a larger pilot. As you have less pressure, the valve wont have to work so hard to shut so all is well.
not sure how this'd go with high pressure low flow...

My FIL 'Steve S' http://www.backyardaquaponics.com/forum ... file&u=469 has doctored some of these valves and says they work well...

You can get 0 pressure valves but they are expensive. You can find them second hand on most water treatment facilities, so look for boilers, cooling towers etc if you're a dumpster diver.

Hope this helped

Or a ball valve and a spit roast motor... hehe. Works a charm...

EDIT: Here Towards the Bottom...

TimC,
I love your approach. It's something I hadn't even thought of. I was trying to find an actuated 3-way ball valve that I could afford, now I'm going to figure out how I can cobble one together myself!

thank you.

3way ball valves are not cheap around $50 and up to $300, but I would suggest you think of trying a windscreen wiper motor, They have HEAPS of grunt. and are 12V, I believer they will run reliably on 6V.

You will need 2 microswitches, best set up with a cam on the main shaft. They use wiper motors and cams with micros on automated swing gates - check out your neighbour's for inspiration.

Also see if you can get a wiper motor with the 'park' function built in. this will reduce the amount of electronics you need as it has a mechanical latch on it, so all you need is 2 micros for control.

Similarly, you could build a brush to maintain contact, just like the park function does... Hmmm ilike the sound of this project...
if you want me to draw any ideas or anything for you I wouldn't mind being remotely involved with this project, it has an element of 'coolness' that appeals to me.

I had thought of wiper motors. Even though they have a lot of grunt they are not geared correctly to give the starting torque. The other thing is that they use a LOT of current. I am talking 12V @ 2-4A. Where as a rotisserie motor runs off 3-5volts at only 100mA.

Hey if you've got it, flaunt it. The grunt that is. I know nothing of Rotisserie motors. The only advantage I will state is the 'park' functionality built into some wiper motors.
This is a brush that maintains power until the motor gets to a certain position, regardless of you having removed power to the terminals.

Also they will have HEAPS of starting torque from my experience.

But if a rotisserie will cut it then sure, use one, they will draw less current, and as they run a slower output shaft there'd be less chance of overrunning your switch.
And parking brushes aren't hard to implement. Are rotisserie motors low voltage? or are most 240? or 110 for our US Friends?