We are striving to find renewable energy sources, either by improving current designs or by harnessing wasted energy. As today's world becomes increasingly aware of the advantages of reusable energy, it is becoming very beneficial to look for sources of wasted energy in everyday life. When people play in parks, the energy that they apply to the equipment in the park goes to "waste." The energy output during their play often works to create a torque on some piece of equipment, which then translates into rotational kinetic energy, which is then transferred to heat energy through frictional forces. By "waste," we mean that this rotational kinetic energy is not harnessed into a form of energy that we could use later; instead, being converted to thermal energy, which is lost to the surrounding space. We could use this potential source of unused energy to power much-needed electrical devices, such as lighting, which can help increase safety and comfort in and around the park.To solve this problem, we need to design a way to convert the rotational kinetic energy applied to the park equipment into a usable form of energy. While there is a wide array of possible equipment that we could use to harness this energy, we focused on the seesaw. While moving up and down, we think that our seesaw could produce a sustainable energy source to help reduce electricity needs in parks. We hope that this prototype can play a role in the real world or lay the foundation for the next generation of energy innovation.