Water Pump Control

Posted: June 30, 2013


I never understood why rich people and fancy places seemed to feel the need to have creepy water fountain statues, so I decided to make my own to see if I could figure it out. So my first step was going to the crafts store to get some self hardening clay. For my first attempt to make a statue I took a water bottle, cut some holes in it, and molded clay around it. Within a couple days after it fully dried, the clay ended up shrinking around the bottle and basically just cracked off. The water bottle seemed like a good idea since it would be water-proof in the holding tank, but I guess this doesn't work. For my second attempt I just molded the statue without a bottle. Seemed to work, but when water was added to the inside, it causes it to crack all over. Well, it was enough to make one video so that's all that matters. Since I put it together in steps (body first, arms and legs the next day, and the head after day 3) the parts didn't stick well so I had to use a bunch of epoxy to hold it all together. Because of that I decided to paint it to hide the epoxy. I'm a pretty terrible artist and this thing came out very crude and childish looking. Absolutely perfect.

In the back of the statue I attached 4 wires. The bottom two wires detect if the statue is low on water and the pump needs to turn on, and the upper two wires detect if the water is high and the pump should stop. I found out that water is a terrible conductor of electricity (found out by the statue overfilling and spilling water all over the place) so I used a couple high gain transistors to deal with this. I put 3.3v into the water with the first wire and ran the second wire into the base of a transistor. Problem solved.

The code is pretty simple running on an MSP430G2231. The source code below can be assembled with naken_asm.

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A video of the fountain pouring water into my kitchen sink.


Water pump circuit

Here's the circuit board.

Water pump in water

Here's the pump that I got from Lightobject. Have to say, I'm pretty impressed with how quiet this pump is and how much water it moves.

Water pump statue

Here's the statue from the back with all the wires hooked up for sensing water level.

Water pump schematic

And here's the schematic...

Source code

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