*2.1. The System of EM Generator*

#### 2.1.1. Conceptual Design

Figure 2 shows the two proposed designs of the generator system in Genpath, with the only difference in the mechanisms for the movement converter. A set of Genpath comprises a floor-tile block embedded with the translation-to-rotation conversion mechanism which is connected to the DC generator and the PMS circuit board. The entire dimension is 40 <sup>×</sup> 40 <sup>×</sup> 10 cm3 with the maximum allowable displacement of 15–20 mm. Two types of mechanisms, rack pinion and lead screw, are used to convert the translation from a footstep to the rotation of the generator. For the rack-pinion mechanism in Figure 2a, the pinion connected to the floor-tile drives the DC-generator shaft through the additional pinion gears which help transform low-speed power to high-speed power. For the lead-screw mechanism in Figure 2b, the nut fixed to the floor-tile's center moves up and down and drives the lead screw to rotate about its axis. The set of bevel gears transmits the rotation from the lead screw to the DC generator and changes the direction of rotation by 90◦. The rotation of the DC generator in both designs then induces the voltage. The springs with the maximum displacement of 15–20 mm connected to the four corners of the block help restore the top floor-tile back to the equilibrium position. Considering the limits of the dimension and the displacement, thus, the small size of 12/24-V-DC motor was decided for the DC generator.

**Figure 2.** (**a**) Rack-Pinion Design; (**b**) Lead-Screw Design.
