Abstract: According to the present invention there is provided a module for use with a chair having a seat portion supported by a support portion, for triggering movement of a person sitting thereon. The module is adapted for attachment to the chair between the seat portion and the support portion, and comprises a driving motor, a base platform adapted for fixed attachment to the seat portion, and an angled axis system (AAS). The AAS has a main rotary element having a main axis, and an auxiliary rotary element having an auxiliary axis and coupled with the first rotary element so that the auxiliary axis is oriented at an angle to the main axis. The module is designed such that when the main rotary element rotates about its main axis, the auxiliary rotary element also rotates about the main axis.