CAD design for a piece of functional recreational equipment that produces a useful output (e.g. electricity)

I am seeking the services of a competent and creative Engineer, who has experience with CAD (Solidworks/Inventor) to design a piece of functional recreational equipment, that can harness a users energy to produce a useful output (e.g electricity). The design should be suited for the use in a children's playground so should be fun and safe. [What the project requires:] -A suitable idea for an item that can be used (in a children's playground) to harness a users energy and turn it into a useful output (for example- generating electricity using kinetic energy). -A detailed CAD design of the proposed idea with around 10-15 parts showing the necessary material tolerances. It should be clear how the equipment functions. Part drawings should be included. Any bearings/gears/chains used should be selected according to the design requirements (loads/lifetime/RPM etc.) - Some simple calculations showing the useful output of the equipment. [Who I am looking for:] -Someone with experience in design/engineering, and is proficient with CAD. Solidworks or Inventor. -Reliable with good communication skills. -Responds to emails. -Creative! If you would like further information regarding any aspects of this project please contact me.