Drip Governor - A most valuble first hack

[jstrack2]

Here is a little video showing what I was talking about in the CAD files I posted last week. I put food coloring in so the water is easier to see:

I used a neodymium magnet I had laying around instead of iron since it had a nice shape, performed well and won't corrode. Therefore Here is a video of it going up and down:

It only uses about 50 mA at 5V. I used 36 gauge copper magnet wire btw, but a little higher gauge may be better. Also a smaller PVC adapter would be better, but the one I used was just what they had at a local hardware store. It has a diameter of about 27 mm. A tube can be glued to the top and bottom of it, or to have things sealed you can use a little PVC cap. That way to clean things all that is needed to be done is just pull the little PVC cap off and it can be everything can be super easily cleaned then. Since it uses so little of current a transistor is not needed to power the solenoid (even if powered by a microcontroller), although a diode should probably still be used to protect against backwards voltage. Here is a picture of the rubber ball glued to the magnet and a picture of the PVC with the solenoid glued on:

halfball.jpgPVCsolenoid.jpg

The total cost of everything I used is only a little over one dollar, and especially if bought in any volume could be less than a dollar. It should be very reliable too. Nothing should corrode (I think the rubber used in bouncy balls won't, but worst case things can be coated). If the solenoid was only powered for a small fraction of a second (instead of me slowly flicking a switch) then only a tiny amount of water would flow through. So the software could totally control exactly when and how much water flows through. I think that this will be cheaper, more reliable and more precise than using a pump. Let me know if anyone has any questions or would like me to show something else (like actually having the tubes attached for example).