Upon being assigned this project, it became apparent that I would need to get creative with the design in order to challenge myself as an engineer. A birdhouse can have a creative form, but I wanted to add a creative function—something that’s not common among many birdhouses.
One idea I had was to use a DC motor to make a moving component. My first thought was to make a water pump with the motor and have a waterfall/birdbath on the birdhouse, but I quickly abandoned the idea because it would require far too much maintenance (replacing batteries, adding water, cleaning, etc.).
Then, I looked to something that would require less (or no) maintenance but still had a moving component. We landed on two ideas. One was to use a horizontal axis wind turbine to turn a camshaft, making the roof of the birdhouse oscillate and have a cool, wavy motion. The other was to make a fully sustainable birdhouse. This would require some form of renewable energy that could power lights, attracting bugs for the birds to feed on. We decided on this direction because it felt the most creative and thematic. Without the budget for the birdhouse, the renewable energy would have to be wind as there weren’t any solar panels lying around the building.
Through some research, I discovered that you can actually convert a DC motor into a generator. By spinning the top, it reverses the flow of current so that you can wire in something, like lights, to the other end and it will power them. The turbine would need to be a vertical axis wind turbine in order to tie in well with the overall design. We chose the QR6 design, which has a cool helical shape that we could tie the form of the birdhouse to and have the best performance for our application. It’s often used in urban environments due to its aerodynamic performance and its helical blade shape, which distributes loads evenly across each blade, reducing noise and vibration.
The next challenge was how to mount the turbine on the pole of the birdhouse without holding the turbine in compression and only using components around the building. It soon became apparent we would need to buy bearings to fit around the pole so the turbine would be able to spin freely. Our project leaders strongly supported mounting the turbine on the pole, so we were granted “buying power” to purchase these bearings.
We also ran into the challenge of turning the motor fast enough to power the lights. To troubleshoot this, we gear-drove the motor. This was easier to do with the turbine mounted on the pole because its rotational speed is greatly increased when transferred to the motor.
All in all, I’d say we were successful in adding a unique and creative function to the design and I found this challenge refreshing.