Splash-Pod: The Personal Water Park

Step 8 Building the water circuit

The four solenoid valves are what make all of this possible. They are the single most important component to the whole project. I bought them from a vendor on Ebay . Generally speaking, a solenoid is an electrical / mechanical device which transfers electrical energy into mechanical energy. So a solenoid valve is a relay which, when activated, opens up a valve. When it is not activated the valve automatically closes. All of this takes place pretty fast. You use solenoid valves all over the place - in a fountain drink machine, for example, when you press your cup against the lever, an electrical switch is being depressed which tells the machine to start pumping your coke. I'm doing the same thing here, when the button is pressed, the solenoid valve opens up and allows water to pass through to all of the toys and water jets.

The operation of a solenoid valve is very simple - power it on and it opens. Inside the solenoid is an electromagnet which sucks the valve stem into a chamber. It is pulling against a mechanical spring so that by default (un-powered) it wants to close the valve. This way, under no power, the valve stays shut. This works great for the toy because the kids can walk up to the various buttons and open individual valves to activate certain functions inside the tub.

I designed this using 1/2" PVC because I wanted something permanent and leak free. It needed to be able to withstand both the high pressure coming from the tap as well as rapid pressure changes from kids repeatedly tapping buttons. I didn't think that flexible hose would work for all of this. I also made the mistake by thinking that PVC was cheap. I incorrectly assumed that since these little fittings were only $0.39-0.89 each, it wouldn't be that bad. Little did I realize just how many of those cheap components I would end up buying. Regardless, PVC was a solid choice in the end.

Throughout this guide, I will try to document most of the steps in the pictures as well as describe an overview here in the text.

There are plenty of guides online and on Instructables about working with PVC so I won't spend an inordinate amount of time on this. The simple explanation is to plan out your project loosely, then dry fit all of the components to the fittings. When you make the cuts, measure an additional 0.5-0.75" for the slip fittings. Prime the ends of the PVC with the purple PVC primer and then apply a fair amount of PVC cement onto both the male end of the pipe and the female fitting. Quickly insert the fittings with a fair amount of pressure while giving it a quarter turn to ensure proper coverage and provide a good seal.

1. Lay out the project path in line with your chosen route.
   • My path follows this flowchart shown in picture #1.
2. PVC cement is best joined with a 90° turn as you are pressing the pieces together. Because of this turn, we want to ensure that we are only joining the straight pieces to start and not combining too many bends.
3. Begin the PVC cement with the straight pieces. Join any pieces that do not require any combination of bends.
   • Straight to Elbow - join these pairs now, but do not join two elbows to a straight yet.
   • Straight to Tee - join these pairs, but do not join any other bend to the straight yet.
4. I joined all of the straight pieces first so that I can correctly line up the combination of bends to face the same direction and be as close to the same plane as possible.
   • Two elbows on a single straight, for example: two vertical elbows on a straight pipe. Both vertical arms need to be pointing the same direction without much variance. To properly set this, we use a previously cemented straight-to-elbow from the last step and attach a second elbow. Attach the elbow 90° rotated away from the end location and rotate in as it sets. It might help to practice this with a dry run before setting with the cement.
   • To ensure I got all of the fittings pointing in the same direction, I laid this flat on a flat piece of granite remnant I had from a counter-top installation. As soon as I rotated the second fitting into place, I placed it flat against the work surface and made certain that it was in line with the first fitting. This would work on any of the connections in my plan, including the tee-fittings like these:
     • (apparently the Instructables viewer doesn't like special ASCII characters. I had a nifty pipe drawing here)
       • so instead, I'll just describe...
       • Elbow pointing up ->>> straight pipe ->>> elbow pointing down
       • Tee fitting ----> straight pipe -----> Elbow pointing down
       • all of these have to end up facing the same direction.
5. All of the solenoids are connected with pipe thread and join the slip joint with a special slip to FPT fitting. These go on last because they are straight connections (can't mess them up) and are thicker than the bend fittings. Putting them on earlier could mess up the angles.
6. All areas where I use any threaded pipes require Teflon plumbers tape to properly seal the pipe connections and provide a watertight seal.
   • To apply the Teflon plumbers tape, tear off a length of Teflon tape that is approximately four times the diameter of the threaded pipe. For 1/2" pipe thread, cut off a 2" strip of Teflon tape.
   • Wrap the tape around the threads, pulling tightly and wrapping in a clockwise motion. Ensure that all threads are covered.
   • To save time (and my sanity), I did almost all of my pipe thread taping in one batch. This took about an hour but definitely helped speed things along when it came time to use those threaded pipes.
7. On my path diagram, the solenoid opens up into another Tee fitting, which splits into 4 fixed jets and a single high-volume accessory connector. This requires a Tee fitting that has 3 threaded pipe threads, one for the solenoid and two for the two outputs.
   • The first output is the accessory connector, which is attached with a 1/2" tube. I used a copper 1/2" MPT to barbed fitting inserted into the first FPT fitting in the Tee fitting. This was now ready to hook up to the output connector.
   • The second output goes to the manifold for the water jets.
     • To reduce the 1/2" FPT do 1/4" fittings, I used a 1/2" to 1/4" bushing.
     • Next, a 1/4" to 1/4" nipple connects the bushing to the 4-output manifold.
     • The manifold can now accept the fittings for the water jets, depending on the requirements for the given channel. The 'red' channel, for example, used three 1/8" barbed fittings for micro jets and a single 1/4" fitting for a larger jet.
     • It was much easier to build this manifold assembly before attaching it to the final pipe. Spinning the whole assembly with all of the fittings was more difficult.
   • On all four channels, I pre-assembled all of the post-solenoid connections to the Tee before threading the Tee onto the solenoid valve.
8. There are four accessory connectors: two inside the tub and two outside. Both pair are held in place with a similar concept. I tightly sandwiched a pair of FPT to slip connectors together with the chassis material (metal tub for inside, 3/4" wood panel for the outside) in the middle.
   • The interior side of the accessory connector attaches to the circuit with another copper 1/2" MPT to 1/2" barbed fitting. The external side of the accessory connector now awaits the modular toys, or the accessory plugs.
9. The input pipe has to be connected through the small hole in the bottom panel. I did this with a simple bend and placed the pipe fairly close to the ground to prevent breakage in case someone stepped on it.
10. After the entire structure is assembled, we can secure the assembly to the floor of the bottom panel. I used 1" electrical tie-down straps and wood screws and this worked out very well.

That should do it for the water circuit.