In our first prototype of the belt, we were using ROB 08449 buzzers (left side of the image) to give haptic feedback to the visually impaired people.
The vibrations produced by them were perpendicular to axes of the belt and thus got significantly reduced as we taped them inside the belt. Therefore, we needed more powerful vibration motors for our purpose.
We have replaced the current motors with Pico Vibe 9mm Vibration Motor- 25mm type (RHS of the image) as it provides vibrations both in X and Y planes.
As could be seen in the pic, they are slightly bigger in size (25mm length and 8.8mm diameter) compared to 3.4 mm length of ROB-08449 motors. However, both operate at 3V and Pico Vibe produces 13,500rpm speed compared to 12000rpm of ROB-08449 buzzers. This is a significant improvement as our output depends on the efficiency of these vibrations. Further, instead of earlier 6 motors, we now have to use only 3 motors in the belt ( one for each zone- left, centre and right).