Transmorphers: Fall of Man (2009)

In this prequel to Transmorphers -- a sci-fi thriller that borrows heavily from the plot of Transformers -- planet Earth is in peril thanks to a rogue army of alien robots, and it's up to a small group of humans to mount a crippling counterattack. Can Sheriff Hadley Ryan (Bruce Boxleitner), a doctor (Jennifer Rubin) and an ex-Marine (Shane Van Dyke) find the automatons' Achilles' heel before they conquer the planet?