Only wanted to post once it was operational, but perhaps there is some easier way so let me bore you.
In a Flood and Drain system (hydroponics) they use a "Bell Siphon" to drain the grow beds. This is unfortunately a manual process that can only be slowed down by reducing the amount of water you put into your grow They also seems to be a bit temperamental based on YouTube clips. So i want to have a 50mm electrically operated valve that will drain the bed. A Solenoid valve of this size is just too expensive for an experiment.
Here is my idea..a normal ball valve (very cheep) attach an arm with a slot in it. Run a nut with some pins on the side in this slot via a piece of threaded rod been turned by an old 12v battery gun and with the help of a Arduino micro controller you have an electrically operated valve. the treaded rod will be supported at the end and where the drill is attached.
Fully closed. Imagine the flat bar with the slot in it attached to the flat bar bolted to the valve.
As the drill turns the nut will push the bar forward and the valve will start to close.
Fully closed it will be in this position. Just need to add some limit switches so the drill knows when to stop.
Now I can run the pump only when the valve is closed and by adding a sensor in the grow bed I can open the valve when the water reaches that point. The whole process can be slowed down at night because the Arduino has a clock and knows when it is night.
Back to the valve...any improvements or blatant oversights??