Yes, I actually did find a text to hexidecimal converter to create the messages on the signs.
The blue one says, "A Robot Army of Many!"
The black one says, "Always obey the Robot Overlords!"
Conveyor belts have also been created:
With all this progress, I forgot to actually come up with robot enemy ideas. I figure the previously mentioned Robot Overlords would be a good enemy. Something with Blocky seeking missiles also sounds good.