Urban Survivalists

This week we are going to show you how to make a float switch with some really cheap equipment.

The reason we need the float switch is because we need something to turn the solenoid valves on and off in the system. This means that the pumps won’t be able to pump all the water out of the rain barrel. We also don’t want the pumps to continue to run too much and pump too much water into the clean water storage tank because that tank might overflow.  The float switch is the solution to this; it will tell the pumps to turn off when the rain barrels are almost empty and or when the clean water storage tanks  are almost full. This will allow us to, hopefully, never have an overflowing tank or a completely empty tank.

We had to look up numerous float switch products online to see what kinds of prices they were being sold for. Most of them seemed pretty expensive. So we decided to make our own out of a push button. They are spring loaded so that they always have a certain orientation exception when pushed. With this idea we thought we could put a float under the button so that when the water level rose enough the float would push the button in and complete the internal circuit in the push button.

This is a really easy solution, but we needed to see what volume of air we needed to push the button and find a small enough float to fit in the rain barrel inlet. In order to test this idea, we hooked up a small circuit to see how the push button would behave. We hooked the circuit to a battery and LED light, so that when the LED was turned on we knew that the circuit was complete. We found the pushing the button downward completed the circuit and turned the LED on. It seems trivial, but it is important for the orientation of the buttons in the tanks. To see what this looks like, check out the video below:

Steps to making the float switch:

Materials needed:

1. Soldering iron
2. Flux core solder
3. Push button
4. 9V battery connectors, two of them
5. Aquarium Silicon for under water purposes
6. Heat shrink tubing
7. Bung cap to water barrel
8. Wire strippers
9. Drill

Putting the push button in the bung cap:

1. (Picture 1) just shows you the bung cap and the push button that we plan on using. The second picture shows how the push button looks when it is taken apart, since there is a ring and washer on it.
2. (Picture 3) shows us measuring the diameter of the push button so that we know what size hole to drill into the bung cap.
3. (Picture 4) shows us drilling the hole in the bung cap with the drill press.
4. (Picture 5) just a visualization of what the hole looks like after it has been drilled.
5. (Picture 6 & 7) show the placement of the push button into the bung cap.

Soldering the wires on:

1. We started by drilling a hole in the center of the bung cap large enough to fit the push button through. Orient the push button so that the plug connections would be on the outside of the barrel if you screwed the bung cap back into the barrel. Please see the picture set above for reference.
2. (Pictures 1-4) Take the aquarium silicon and place a small amount near the base of the plug connections but not covering them.We will put more on later.
3. (Picture 5 & 6) Heat up the soldering iron and take one of the 9V battery connectors. Use the wire strippers to take away the plastic away from the ends of the two wires.
4. Cut two pieces of heat shrink tubing and put one on each wire. Not shown.
5. (Picture 7 & 8 ) Then loop the end of one wire into the hole on the one of the push button wire connector. It doesn’t matter which one.
6. Use the soldering iron to heat up the connection, then use the soldering wire and melt some of it onto the connection. Wait for it to cool, and then do the same to the other wire.
7. (Picture 11) Next, hook the wiring you just made up to the battery and LED to test to make sure that the connections will still conduct electricity. If not, use the soldering iron to melt the solder and redo the connection until it does turn the light on.
8. (Picture 9) If it works, then use the soldering iron to melt the heat shrink tubing over the connection you just made.
9. (Picture 12 & 13) Now finally, place more of the aquarium silicon over the connection to make it water tight.
10. Done! (Picture 10) for completed appearance.

Making the float part of the float switch:

Now we are going to be retrofitting a bottle so that it will be fit into the hole on the top of the rain barrel while keeping in mind that it has to displace enough water to create enough force so that it actually triggers the push button. It’s not really a technical thing, we just needed a way of sealing the bottle so that it would be air tight, so we used water proof epoxy that takes 50 minutes to cure. We also used scissors and another plastic bottle to extend volume to the first one.

Materials:

1. Water proof epoxy glue
2. Scissors
3. Old Plastic bottle, preferably small enough diameter to fit into bung hole cap
4. Sand paper
5. Two medium paper clamps

Steps:

1. (Picture 1-3) Start by cutting the top off of the smaller bottle and top and bottom off of that larger plastic bottle.Cut down the center of the larger plastic bottle to form a rectangular sheet.
2. (Picture 4) Now make a smaller cylinder out of the rectangular sheet and size it so that it fits inside the smaller bottle.
3. (Picture 5) sand the surfaces that the epoxy is going to glue to.
4. (Picture 6-9) Mix and apply the epoxy to the edges of the bottle that you just sanded off.
5. (Picture 10-11) Roll the rectangular piece into a cylinder and let dry. This will later be attached to the other bottle to incease the volume of the water bottle so that it will have enough force to move the push button.

We plan on taking the enlarged water bottle we just made and retrofitting it onto the push button so that it won’t come off while it rises in the tank. This seems like a finicky process and we are still working out some kinks on how to keep the bottle completely upright while it is in the barrel. So if you have any ideas hit us up! That’s it for this week P&S

Related posts:

1. Water Filtration Construction Phase 10
2. Water Filtration Construction Phase 9
3. Water Filtration Construction Phase 8
4. Water Filtration Construction Phase 6
5. Water Filtration Construction Phase 5