SnackTrap

State 1: Welcome to SnackTrap
State 2: Buzzer Sounding when Snacks Approached
State 3: SnackTrap Closed for Snack Protection
State 4: Reopening of SnackTrp by Owner
SnackTrap Code

Inspiration (What's the idea?)

Our idea was to create a snack trap to protect your snacks from friends that visit. If you like to leave your box of snacks open so that they are easily accessible (like we do), then this is a handy way to be warned if someone tries to reach into your box of snacks to steal something. The box starts out open, and when a hand is sensed within 100 cm, a buzzer will sound and the box will close once the hand has moved far enough away for it to snap shut without hurting them. The buzzer then stops until something comes nearby again, and the box can then be opened at any time and the process restarted by a switch that only the owner has access to.

What it does (Explanation of the hardware/software)

Our first component is an ultrasonic sensor that detects how far a hand is away from the box, and if it gets within 100cm, a buzzer is triggered. We have an LCD screen that shows “Angry!” when the buzzer is going off due to someone coming too close, “Closed” when the person’s hand is far enough away that it can safely shut, and “Open!” when the owner presses the switch after the box has been closed. We have an additional potentiometer and resistor to help the functionality of the LCD and the switch, respectively. What would you add if you could have built this in person (sensors, hardware, 3D printing/laser cutting etc.)?

How we built it

We first thought about our idea and scrolled through the list of available parts on TinkerCAD. We selected components that we thought could accomplish the different tasks, and looked up how to program and wire them. We chose to use an LCD screen to reflect the state of the box (open or closed) and a switch to represent the user putting in a password to open the box.

Challenges We ran into (What would you add if you could have built this in person?)

If SnackTrap was realized in person, a box of laser-cut acrylic would have been constructed. This physical box would then have a motor controlled lid that would shut upon “closing,” which is modeled in TinkerCAD by the Liquid Crystal Display. Additionally, an ArduinoMax would have been employed so that we could’ve used a keypad, for the owner to input a password, rather than flip a simple switch. The initial design for SnackTrap included a keypad so that the opening and closing of the box would be in the control of the owner, who would be the only person with the password. Because we used an LCD to model the opening and closing of the box, the number of pins which we were able to use were limited on the ArduinoUno. We would also have used the ability of the Arduino to send a notification to the owner’s cellphone if the box’s buzzer was triggered, in case they are too far away to hear it. This would have been accomplished by incorporating a bluetooth sensor that could update the owner about how their snacks are fairing by sending a bluetooth signal through the Internet to their phone.