Hi, my name is Abhishek Prasanna, and recently I did an engineering course made by Mark Rober. I have already written a post about this, but there were two other builds that we did for the course. This post is about the first build: a purely mechanical build. No electrical components allowed. We decided to make something called the Snacker Slapper, which would give you a slap when you took snacks from a box.

The Process

Brainstorming

First, we had to come up with an idea for what to build. We were prompted to create a build that had something to do with food. We instantly thought about people eating too much/when they are not supposed to. Impulse snacking is an example of that. We decided to make a build that would give you a whack when you took a snack.

Research

Next, we had to do some research. How were we going to accomplish what we wanted? At first, we thought we rig this up to the pantry. How it would work is: there would be rails on the side of the pantry with a wooden board attached to them. This board concealed the hand that would slap you. When the door was opened, the wooden board would slide on the rails, revealing the hand. The hand had a spring right behind it, so the spring uncoiled, and propelled the hand into the thief. However, we found a problem with this design. The hand would have to be short enough to fit in between the shelves in the pantry, but long enough to reach the person. This wouldn’t be possible, so we decided to fix the problems by moving this to a box. We realized we would have to make our own box so that we could choose the dimensions (we chose the box to be 1 ft x 1 ft x 1 ft). We would have the hand on the outside of the box, and when the lid opened, a board would uncover the hand, which would slap the stealer. But before we went to buy the supplies we needed, we found a better way to control when the spring released: a magnet. The hinge would stick to the magnet and when the lid was opened the magnet, which was holding the hinge in place, disconnects from the hinge, allowing the spring to uncoil.

The Build

We bought supplies and built our prototype. Here is a video showing how it works: https://www.youtube.com/watch?v=qmUU69oq-ac. This video just shows the prototype though. We made some more tweaks before the final build. The biggest one was connecting the magnet to the hinge through the inside of the box. It looks much better, and is more efficient, although it does leave less room in the box for snacks. Here are some pictures taken throughout the process.