Once we began building out final preliminary design from the end of first semester we realized that the design was overly complicated. This could lead to a reliability issue from extra moving parts and we saw a chance to streamline and simplify our approach, along with saving a few dollars along the way. We scrapped the spool and solenoid in favor of a simple twist/untwist internal motion provided by a motor. This option materialized through the use of flexible zip-ties that could reasonably hold their shape once spooled out of the can. This allow us to lose the spinning motion of cords for a pulsing motion from the zip-ties.

Also removed from our first semester design was the use of two speakers. We discovered through testing that we could not create a viable infrasonic sound from the speakers we had chosen. Upon review of the cost versus efficacy of this scaring mechanism we chose to remove the speakers and use the saved money elsewhere.

We added a vibrating motor in lieu of the replaced speakers to add another scaring effect. The motor (which can be seen attached under the right bracket below in yellow) is coded to to run every other trigger or at random, as the coding is very flexible and will be finalized at the end of semester.

Inside of Device

Design Operation

As seen below, the device is still contained within a paint can, with the solar panel mounted onto the removable lid. The PIRs still remain on the sides with slits at the top for the zip-ties to move through.

Zip-Ties Retracted

Once the device is triggered, the zip-ties will unspool and pulse once fully extended. Depending on how we program the device, the pager motor will also fire, creating a whir against the side of the can.

Zip-Ties Extended