Lower limb exoskeletons are today an excellent rehabilitation device in patients who, due to an injury (e.g., stroke or spinal cord) or due to age, have reduced gait mobility. It cannot be ruled out that in the near future, in addition to rehabilitation, they may be used in everyday life to return to regular walking. Up to now, there are various models on market that can be used for the latter purpose, or for the research and rehabilitation, however they are generally expensive and therefore, not very accessible. This thesis aims to develop an active lower limb exoskeleton, taking inspiration from an existing low-cost and open-source exoskeleton called ALICE.