Implementation

Demo Day

Because of the limitations of space during demo day, we were limited to turning on the skateboard to show that it triggered the remote (and subsequently the motors) by shaking the board fast enough.

Acceleration Threshold

We found the threshold to be 4 m/s^2, meaning that at 4 m/s^2 the accelerometer will determine that the user has pushed the skateboard and the motors will trigger. This is also higher than the standard acceleration of putting down and picking up a skateboard, as well as getting off the board, so that it won't trigger the motors when the user causes movement typical of standard usage.

Run Time

We also determined the run time (how long we wanted the motor to be on for) to be 0.3 seconds. This run time was the optimal length that allows the user to be boosted by the board, while still providing a natural feel.

Troubleshooting

We made sure to only count acceleration along the y-axis of the board (the axis that extends through the front and back of the board). This causes the accelerometer to ignore upward (toward the user) and downward (toward the ground) acceleration. This additionally allows the the board to flex, resulting from a shift of weight from the user, without subsequent triggering of the motor.

In addition, because our motors are controlled by acceleration, during testing we noticed that the acceleration of the motor would cause multiple subsequent triggers of the motor itself. This caused the skateboard to accelerate in an unnatural way for the user. In order to solve this problem, we included an additional measure of run time in the controls. The arduino essentially, does not allow for the remote to send a signal to the motor within 2 seconds of a previously sent signal, thus preventing the motor from triggering multiple times within a short time frame.