LEGO Jumpers and Hoppers
These Jumpers use the same type of 4-bar linkage as LEGO Punchers, angled to push down to drive the mechanism up. They can also be modified to hop in a direction by changing the angle that the linkage is attached to the frame, or by changing the lengths of the linkage's bars as simulated below:
Jumpers can also be made to hop directionally by adding angled toes and orienting the front and back legs in the same direction, as can be seen in the following video:
Those methods only allowing hopping in one direction. Alternatively, motorized Jumpers can hop in both directions by changing the timing of the front and rear leg's jumps - below are a few experiments of this idea:
This is more of a test of the concept of hopping rather than a robust hopping robot, and it could be improved a lot. If we dial it in then we'll post some detailed building instructions. For now, below are some pictures of this build from various angles.