Vibration energy harvesting is a growing field of research. Harvesting energy from vibrations can be of use in devices in hard to reach places, such as sensors on a train track or a pacemaker. These devices makes use of batteries, which need to be replaced. Using energy harvesting this battery life could be improved. The difficulty lies in harvesting low frequency vibrations. These vibrations are hard to harvest using a transducer such as a piezo. A solution could be using a frequency up converter, which can raise a vibrations frequency. This thesis shows the design of a Bi-stable Impact-driven Snap-through frequency up converter (BISup). Enhancing the behaviour of this bi-stable design could improve the energy harvesting capabilities. Different designs are made using ortho planar spring design, these designs are simulated and compared using ANSYS. These simulations are experimentally verified.