Custom DC-Controlled Electromagnets updated

I need three compact electromagnets fabricated for integration into a larger prototype. Final outside dimensions will be supplied once we begin, but each unit must: see diagram attached • Run from a standard low-voltage DC source (anywhere in the 12–24 V range is acceptable)... (Budget: $250 - $750 AUD, Jobs: CAD/CAM, Electrical Engineering, Electronics, Mechanical Engineering, PCB Design and Layout, PCB Layout, Product Development, Prototyping)