THE LEAN GREEN SALAD

MIXING MACHINE

Project Description

The Task:

Design and build a device that semi-automates one key aspect of living in a motor home.

Our Device:

We built a salad mixer and dispenser that mixes the user's salad ingredients at a desired speed and dispenses the mixes into the user's salad bowl at the touch of a button! Our device produces the perfect salad every time without the mess and effort that comes with mixing a salad by hand! It even makes salad-making fun with groovy music that will make you want to eat a salad every day!

Functionality

Welcome mode
3 distinct user interactions including:
- Non contact sensing
  - An IR sensor that detects the presence of a bowl
- Analog input
  - A slide-potentiometer to control the mixing speed
- Large-scale motion
  - The user must use both hands to close the doors
Display passage of time
- A timing bar that scrolls across the LED display
Parts that visibly move under the control of a PIC32
- A rotating mixing blade visible through the clear container; doors that swing open under the control of a servo motor
Timeout
- If the user does not interact with the device for 20 seconds, it will return to welcome mode

Salad Mixing

The machine is equipped with a DC motor that spins an attached 3D printed mixing blade. The speed of the motor, and therefore salad mixing, is determined by a user-controlled potentiometer in the form of a slider. The slider serves as an analog input and its analog nature is taken advantage of by having a range of mixing speeds. The mixing process is visible through a transparent acryllic container.

Salad Dispensing

The machine has 2 "trap doors" on hinges that are held in place by a servo motor with a symmetrical arm. When in the locked position, the servo arm is perpendicular to the center bridge and holds the middle of the doors up to prevent salad from falling out of the salad container. When the "open door" button is pressed and there is a bowl present, the servo arm rotates into a parallel position between the doors causing the doors to swing open on 2 outer hinges due to gravity.

The doors are closed manually by the user. When both doors hit 2 small mounted switches, pushing the into the down position, the servo arm rotates back to the locked position to hold the doors.

Bowl Detection

The machine is equipped with a IR reflective sensor (non-contact sensing) in the middle of the lower platform to sense the bowl presence. The salad release doors will not open if no bowl is detected, even if the user presses the "open door" button. When the bowl is placed on the platform, blocking the sensor, 4 led lights illuminate, indicating bowl presence. With the bowl present, the user can press the "open door" button to release the salad.

Timing

The machine has a built-in 30 second mixing timer and displays the passage of time via a progress bar on the LED matrix. In addition, the machine has a 20 second timer that brings the machine back to welcome mode if the user has not interacted with the machine.

Audio and Visual User Feedback

The device has a variety of visual and audio messages to the user throughout the salad mixing and dispensing process. While the salad is being mixed, music is played to keep the user entertained. When mixing is complete, a ding sound plays to indicate the timer has run out and the LED matrix displays a "Mix Done" message. LED lights on the corners of the lower platform serve as a visual cue that the bowl has been detected and the user can now open the doors to release the salad. When the doors are open, the LED Matrix displays "GATE OPEN." Finally, there is an audio reminder to take the salad and close the doors. This message repeats every 10 seconds until the task is completed. Once the doors are closed, the LED Matrix displays a "GATE CLOSED" message.

How to Use

Remove the carrot top lid and load the salad ingredients into the acrylic container.
Press the mix button to start the 30-second mixing timer.

a. Adjust the speed by moving the slider up and down.

Place the bowl on the platform under the mixing container.
When the mixing is complete (indicated by a message on the LED display and an audio sound) and the bowl is in position, press the open button to open the doors and release the salad.
Listen to the audio instructions to take the salad and close the doors.

a. Use 2 hands to bring the doors back to a closed-position. You will here a click when both doors are in position. The doors will then be locked closed.

Eat your salad!

Demo Video

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