Bionic arm is a motorized hand that a person missing a hand can control intuitively using muscles in residual arm. Such device was commercialized a half century ago, but it hasn’t been prevailed widely. The reasons are twofold: the price is unaffordable costing more than 15K USD, and choices of design/function are limited against user's various preferences. HACKberry reduced the material cost to the tenth by utilizing 3D printer. Moreover, all the data and sources of HACKberry are available online, expecting creators around the world to provide other designs and additional functions.