Van Project: Hands-Free DC Water Pump Paddle Switch

As we continue to refine the interior design of our van, one of the things we wanted to fix was the water pump situation in the kitchen. As you may recall from original Kitchen entry, we installed a little diaphragm pump in a wooden box to pump water out of our water tank up to our sink. To activate the pump we used a little on-off (SPST) toggle switch. This worked fine, except it was kinda annoying and a waste of water for doing simple tasks like washing your hands or brushing your teeth. Since in order to use the water we had to flip the switch, then start the process of washing and either flip the switch off with wet soapy hands (and then back again again 30 seconds later) or let the water run the whole time. We needed a hands free solution to turn the water pump on and off. Thus the paddle switch idea came into being.

Summary (TL:DR)

We made a hands-free water pump switch by using a momentary on-off (SPST) push-button and wiring that in parallel with our old on-off switch. On top of the button we built a wooden paddle that allows us to put a leg or a knee onto the paddle in order to achieve hands free activation of the water pump. Easy as that.

Tools and Materials

• Usual wood working tools; saws, hammer, screw driver, etc.
• Usual electrical tools; solder iron, wire cutters, etc.
• momentary on-off (SPST) push-button
• wire
• Random assortment of wood pieces to make the paddle and button housing
• wood glue, screws, and nails

Procedure

The entire project only took about an hour – maybe a little bit longer to figure things out, but it wasn’t complicated.

1. using a 1×3 board cut to about 18″ in length we mounted a 1×2 block on one side and drilled out the other with a 1″ hole saw.
   • The 1×2 block we sanded down pretty well so as to create a nice angle that the paddle could deflect into.
   • We placed another thin piece of wood over the top of the 1″ hole and mounted our push-button on to that thin cover piece and put that assembly in the 1″ hole.
2. For the paddle portion, we ripped a thin (maybe a little more than 1/4″) piece of 1×3 on the table saw – a piece of thin plywood would have probably worked here too. This piece was glued and nailed to the block so that it hovers over the momentary push-button.
3. From there we took the assembly and mounted it on our kitchen unit.
4. We wired the new hands-free paddle in parallel with the old switch, so we could still use the old switch to turn on the pump or use the hands-free paddle. Either one will turn the water pump on.
5. In order to avoid accidental activation of the water pump and to keep the paddle from rattling around while underway, we made a little U-shaped block of wood that sits over the push-button (actually kinda looks like Stonehenge). We can also wrap a bungee-cord around the paddle to further eliminate rattles (we’ll see if this is needed.

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That pretty much covers it. A pretty straightforward project, to solve a pretty simple problem.