So this is kind of like a stirling engine. Would this work?
A box that has a crankshaft, and two connecting rods that is under a vacuum (with no air inside of it.) The connecting rods are facing opposite each other and attached to the crankshaft on one end and then to a diaphragm on the other end which is part of the side of the box. The connecting rods are oriented such that when one connecting rod is fully extended it pushes the diaphragm outwards whilst the other connecting rod pulls its diaphragm it’s connected to inwards towards the inside of the box. The flexibility of the diaphragms and the outside atmospheric pressure and vacuum on the inside causes the reciprocating between the two. I am sure a better material could be used but to visualize the concept imagine the diaphragms are both made of rubber.
not trying to make a perpetual motion machine
I know atmospheric pressure difference wouldn’t provide a ton of power in this setup.
Final thot of night