HEEEEEEEELP !!!!! CYCLE TIMER ????

My electronics experience and knowledge is often compared to a piece of wet splintered timber with a rusty nail hanging out of the end, wrapped in duct tape and set on fire…

So… What i need to know… is regarding these things below…

http://www.ebay.com/sch/i.html?_from=R4 … y&_sacat=0

Are these things “Stand alone” or do they need to be hooked up to my computer to function??

I need one to activate a 12V DC solenoid (normally closed) in specific and adjustable time cycles…

Im developing an Aeroponics Growing system and need to supply nutrients via high pressure tubing, released by the opening of the solenoid valve…

The parameters i require would typically be 2 - 5 seconds ON (open) every 3-15 minutes OFF (closed again)… so… small bursts intermittently…

Both the “on” and “off” timeframes would need to be adjustable, until, through trial and error i can determine optimum feed cycles…

It gets better… I will require a different regimen for Night time (e.g 6pm till 6am)… (plants require much less nutrients in the dark) so would need an automatic or “pre programmed” (?) adjustment to cater to this lesser feeding time.

I don’t need to go all STAR WARS with sensors etc, tho, in saying that… is there a simple way of doing just that?

If i could pick your electronics brains and get a result with a nice automated and adjustable DAY/NIGHT feeding regime,either with or without sensors,

Id be one VERY happy camper…

Thanks folks…

I look forward to a reply…

Cheers… and PEACE…