Design 2 and 3 are far too over the top for domestic use and will be far to complicated unless you have an instrument tech
Design one looks like an off the shelf unit and will be unsightly in most gardens.
There is no sump so any grit will collect around the pumps also with the differing head the pump flow rate will be veritable. Pump selection will be difficult also unless vds's are used.
It would be easy for the end-user to drill the necessary holes in the plastic tank and fit as many as needed. Your control would sense when water was required and deliver a predetermined amount by opening the solenoid for x seconds and let gravity do the work that a pump would do (less cost, less battery drain, less to keep gunk free and maintain).
Also consider that if 1 plant needs watering, then it's likely others do too, so 1 sensor could probably monitor a number of plants using 1 sensor as input and maybe 10 hoses delivering water to 10 plants.. You could also add an additional much smaller tank with liquid fertilizer that would dose the main reservoir.
Sounds like a fun project. Is it purely a theoretical exercise or does it have to be practical?
Billericay - Essex
Knowledge is knowing that a tomato is a fruit. Wisdom is not putting it in a fruit salad.
Brilliant Pete, not too complicated to add a single control to make the opening time adjustable by the user either. Could one have some control over the amount of watering at the other end? Like how many holes and their size in the pipe feed to the plant?
Certainly sounds worth considering such a simple approach Adam. Make if for less than £15 and so it is easy to connect to my water butts which are already raised and provide a bit of pressure ,and I'll buy one to water my herbs.
@richhondac Thanks for your feedback. I was planning for metal nails to be used to measure the moisture in the soil. So it would require any other special high tech instruments. Yes, possible grit and unwanted particles may get in and affect it. I shall have a look into it and If a pump is used a filter may be connected to it. And I'm not sure on what what you mean at the end about vds?
@Pete8 Thanks for the idea's, I like that idea. I might replace the sensor with just the one. I still need to look into the connectors which are suitiable. Yes, this project needs to be practical. However, my final unit/system which I build for my project will still only be a prototype so all the bugs and improvements might not all be done. But thanks for the ideas for improvements, I will include that in the discussion of my project so it doesn't go to waste!
However I will need to speak to the teacher as the project needs some degree of complexity which I will design and make the components where possible. I think keeping the prototype under £15 will be quite difficult due to materials costs, etc. but thanks! (Maybe if it was properly manufactured then possibly )
Making it for £15 isn't too restrictive, You can get a 12v solenoid water valve for £8 on amazon, that leaves a whole £7 to spend at Maplin on electronic components and an enclosure/project box. That's loads of money!
It's worth looking at doing it for less than £15 as an exercise Adam, simple/low component count in product design should never be seen as bad if it does the job as well or better than complicated.
Haha xD Yes, that's true I suppose, but I don't think I'll order my components from Maplins as they charge quite a lot for their components. Okay, the cheapest cases they have is £1.00...
I want to say ' Challenge Accepted' but I kinda already have the feeling that I will not accomplish this... But I shall stick to it for now
And the teacher said that my project should be a program orientated project, therefore a PICAXE, Arduino or some kind of PIC will be required. If you don't take into account the cost of that then I might be able to
I would get the basic system working without a PIC using a simple timer chip first.
Then if you wanted to take the concept further and program you could look at the principles of a closed loop feedback system.
For example, if the soil kept drying out over a period of say a week, meaning the unit was operating more often than desired, the water delivery time could be increased, if it remained wet for a long period, the next watering could be a shorter duration. The system could then adjust to different seasons and perhaps also have a user input control for dry, moist wet, some plants like wet roots, some don't
I would hesitate though and wonder if more would really be achieved by using a PIC over the simple sensor/response system.
Posts
Design one looks like an off the shelf unit and will be unsightly in most gardens.
There is no sump so any grit will collect around the pumps also with the differing head the pump flow rate will be veritable. Pump selection will be difficult also unless vds's are used.
just off the top of my head and as a idea, after all it's your project not mine.
if you have a raised tank - like a cold water tank in the home - that's fed from the guttering on the g/house, you could use something like these solenoids-
http://www.eboxtao.com/index.php?route=taobao/taobao&product_id=14695764925
It would be easy for the end-user to drill the necessary holes in the plastic tank and fit as many as needed.
Your control would sense when water was required and deliver a predetermined amount by opening the solenoid for x seconds and let gravity do the work that a pump would do (less cost, less battery drain, less to keep gunk free and maintain).
Also consider that if 1 plant needs watering, then it's likely others do too, so 1 sensor could probably monitor a number of plants using 1 sensor as input and maybe 10 hoses delivering water to 10 plants..
You could also add an additional much smaller tank with liquid fertilizer that would dose the main reservoir.
Sounds like a fun project.
Is it purely a theoretical exercise or does it have to be practical?
Billericay - Essex
Knowledge is knowing that a tomato is a fruit.
Wisdom is not putting it in a fruit salad.
Brilliant Pete, not too complicated to add a single control to make the opening time adjustable by the user either. Could one have some control over the amount of watering at the other end? Like how many holes and their size in the pipe feed to the plant?
Certainly sounds worth considering such a simple approach Adam. Make if for less than £15 and so it is easy to connect to my water butts which are already raised and provide a bit of pressure ,and I'll buy one to water my herbs.
@richhondac Thanks for your feedback. I was planning for metal nails to be used to measure the moisture in the soil. So it would require any other special high tech instruments. Yes, possible grit and unwanted particles may get in and affect it. I shall have a look into it and If a pump is used a filter may be connected to it. And I'm not sure on what what you mean at the end about vds?
@Pete8 Thanks for the idea's, I like that idea. I might replace the sensor with just the one. I still need to look into the connectors which are suitiable. Yes, this project needs to be practical. However, my final unit/system which I build for my project will still only be a prototype so all the bugs and improvements might not all be done.
But thanks for the ideas for improvements, I will include that in the discussion of my project so it doesn't go to waste!
@GemmaJF Yes
I shall have a look at the possibilities of that. I suppose i could use these to adjust water output, the opening times, etc. http://uk.farnell.com/bourns/3386p-1-104lf/trimmer-100k/dp/9355049?mckv=DM0yTqYd|pcrid|46825333509|plid|&CMP=KNC-GUK-FUK-GEN-LISTINGS
However I will need to speak to the teacher as the project needs some degree of complexity which I will design and make the components where possible. I think keeping the prototype under £15 will be quite difficult due to materials costs, etc. but thanks!
(Maybe if it was properly manufactured then possibly
)
Adam
Making it for £15 isn't too restrictive, You can get a 12v solenoid water valve for £8 on amazon, that leaves a whole £7 to spend at Maplin on electronic components and an enclosure/project box.
That's loads of money!
It's worth looking at doing it for less than £15 as an exercise Adam, simple/low component count in product design should never be seen as bad if it does the job as well or better than complicated.
Haha xD Yes, that's true I suppose, but I don't think I'll order my components from Maplins as they charge quite a lot for their components. Okay, the cheapest cases they have is £1.00...
I want to say ' Challenge Accepted' but I kinda already have the feeling that I will not accomplish this... But I shall stick to it for now
And the teacher said that my project should be a program orientated project, therefore a PICAXE, Arduino or some kind of PIC will be required. If you don't take into account the cost of that then I might be able to
Adam
I would get the basic system working without a PIC using a simple timer chip first.
Then if you wanted to take the concept further and program you could look at the principles of a closed loop feedback system.
For example, if the soil kept drying out over a period of say a week, meaning the unit was operating more often than desired, the water delivery time could be increased, if it remained wet for a long period, the next watering could be a shorter duration. The system could then adjust to different seasons and perhaps also have a user input control for dry, moist wet, some plants like wet roots, some don't
I would hesitate though and wonder if more would really be achieved by using a PIC over the simple sensor/response system.
Ah, okay I understand you now. I will be trying out the simple systems soon
defiantly before end of Jan.
Adam