Hello everyone
As titles says i'm trying to do that:
My Problem is marked with the red square. i have no idea how to connect the outlet to the different tubes going to the individual plants. I saw one solution with an servo Swinging one tube from one plant to another, but this isn't going to work for me.
i thought about Solenoid valves, but they often Need enough pressure to really open and it would be quite expensive in the end.
Has anyone got any ideas?
Sincerely
bluebubble
Direct acting valves don't need pressure.
A pump might be in the same price range as a valve. So you might as well use many pumps.
This is a direct acting valve:
http://www.ebay.com/itm/141292113590
http://www.ebay.com/itm/131225288079
This water pump is halve the price of a valve:
http://www.ebay.com/itm/221588471808
http://www.ebay.com/itm/141452338285
Hi, not sure what country you are from, but most of the DIY stores cater for automatic watering systems, it would be worth looking there if you can.
They would have low pressure, low voltage valves and such.
Tom..... 
Hello everyone
thanks for your replies! i deceided to order 8 pumps through that chinese dealer. he's got some incredible low prices, holy sh*t.
so my new approche is to drive those dc motors with an 12 v power supply and a darlington driver.
i dont want to leave the motors on 12 volts all the time so i put a relay between them and the power supply, to save the heatsink on the darlington driver and save some power. the relay is controlled by the mc.
to save some pins on the arduino for future developement, the darlington driver is driven by a shift register directly controlled by the arduino.
the picture misses the details, it's only pupose is to get the idea across.
does it make sense? also i wonder if the noise on the powerline from running the motors could make the arduino not work properly. if yes, would a capacitor connecting the lines going the arduino even out that noise sufficiently?
sincerely
bluebubble