Power Generating Turbine for Drainpipes

I recently saw a house that had its waste water pipe going into a drain on the outside of a house. This made me think -is there a way to gain energy from this? This is why I have created this turbine. I wanted to generate energy in a way that would be easy and give lots of uses. In my prototype I have it lighting an LED (which is taking the place of garden lights in my case).

What you need:

• 3D printed parts (or purchased equivalent)
• Various VEX IQ/VRC parts (depends on space available and different motors)
• Quick set epoxy resin
• Motor (preferably brushless)

As shown by the many images, I went through many iterations of the design using fusion 360. I first tried to create an especially reinforced version by using a large top plate. However, I decided that this would be too inefficient and block too much of the water (as well as wasting too much unnecessary plastic), so I went for a simpler three pronged design. You can also see that previous shafts and bevel gears that I planned to 3D print never made it too the final design. This was because I thought that they wouldn't 3D print well enough to be worthwhile and that I would have to replace them anyway. That is how I settled for the final design and it is linked below.

First, using the quick set epoxy resin secure a small vex shaft to the bottom of the turbine rather than the much less accurate 3D printed one. Attach one bevel gear to the shaft after threading it through the hole in the shroud and then attach the second to a long metal shaft threaded through the shroud side holes (see picture). Adjust the height of the first bevel gear until they fit together snugly and then secure both gears and the long metal shaft with stoppers as shown.

I added a base to be able to secure the 3D print to the motor next. For this step, making this base will depend on what VEX pieces you have available and the size of the 3D print. I recommend playing around with it until it fits snugly.

This step is very similar to the previous one in that it will depend on the size of the 3D print and what you have available. However, you should also adjust the gear ratio to the motor to make sure you can get maximum efficiency.

WARINING: ALWAYS TAKE CARE WHEN MIXING WATER AND ELECTRICITY AND MAKE SURE THE CIRCUITS ARE PROPERLY COVERED. ALSO, IN MY CASE I AM USING AN LED TO REPRESENT GARDEN LIGHTS, HOWEVER, I AM USING NO RESISTORS OR CAPACITORS TO PROVIDE A STABLE VOLTAGE DUE TO THE FACT THAT I DO NOT CARE ABOUT THE HEALTH OF THE LED. FOR ANY OTHER PROJECTS, ALWAYS PROVIDE A STABLE VOLTAGE.

Now that is out of the way...

In my case I am doing an extremely simple circuit, I am just plugging an LED into the motor using wires as the prototype. However, this is bad practise and more care should always be taken. The LED is to represent garden lights, however many other possibilities are out there, such as: charging a phone (or even a torch or some other hand-held device), powering a lamp, or if enough power was eventually generated, you might be able to power gardening tools. I hope you enjoyed this!