# Title Team Members TA Documents Sponsor
60 Self Cleaning Table - Revised
Anders Cox
Armando Terrones
Kevin Thompson
Ruhao Xia design_document1.pdf
Anders Cox: ajcox2, Armando Terrones: armando2, Kevin Thompson: krthmps2

# Problem
Customers expect a restaurant to be clean enough for safe food consumption and limit the spread of disease in public places. However, studies* show that the tabletop can be one of the least sanitary parts of a restaurant, often containing more germs than the toilet seat. Although restaurants are required to wipe a table after each use with disinfectant, they often use the same rag all day, effectively spreading the germs instead of killing them. Employees also tend to miss certain parts of the table, if not forgetting the table completely. This leads to the spread of sickness and unhappy customers.
*2017 quote on Today show, Dr. Charles Gerba, Microbiologist, University of Arizona

# Solution Overview
We propose to design a table which cleans itself after each use.This design is specifically for rectangular tables, where the legs are in the center and people are seated on the two longer sides. The cleaning system is a single bar which spans the table and holds the cleaning tools. The bar is held up by a pair of rails, which are mounted on the underside of the table. These rails sit almost flush against the underside of the table, allowing just enough room for the ‘handles’ of the cleaning system to hold on to them. Next to one of these rails is a gear track, which allows the system to move via a motor and an aptly sized gear. A single motor should be enough to move our entire system, because we will use ball bearings to reduce friction against the guard rails, and we will keep the system itself as lightweight as possible. When not in action, the tools will be removed from the surface of the table, and hidden inside a small case on one of the unused ends of the table. In this way, we minimize the impact of our design on both the tablespace and legroom.

A sketch of this design is here:

A passive IR motion sensor mounted on the underside of the table will be responsible for detecting patrons. If people leave the table for sufficiently long, then we will automatically begin cleaning. As the cleaning system begins moving, the tools are initially raised slightly and the sprayers are off. IR break beam sensors are mounted at the front of the cleaning system, and will detect any large objects left on the table. If anything is found, then the cleaning cycle will be halted and the tools retracted. A warning light will signal that the table was unable to complete its cleaning cycle, and the system will wait for someone to come clear the table. If no people or objects are detected as the bar traverses the entire length of table, then we will lower the tools to begin spraying down and wiping off the table, moving back towards the housing. More break beam sensors on the back side of the system will also double check that the table is still clear, and cause the system to halt if something is found.

The housing at the end of the table will contain a drip pan for any drippings off of the cleaning tools. There will also be a container for disinfectant spray, and a small pump to send it to the cleaning system. The control system will lie either inside or right next to the housing, on the underside of the table. This will connect to the sensors, as well as the speaker and status LEDs on the top of the housing.

## Novelty of Idea
- Automation guarantees consistency in the cleanliness of table
- Relieves employees of work
- Speedy automated cycle for fast usage
- Scalable to many sizes of table
- Cleans directly after use, making table easier to clean
- Only requires employee bussing for large objects or major spills
- Minimal regular maintenance of emptying drip pans when full and occasionally replacing the drying cloth

## Competition
- Low competition since this is a novel idea
- Main competition is Cleaning robots that operate similar to a roomba
- Issues with cleaning robots that our ideas solves
- Long cleaning cycle
- Must be removed after use
- Typically too large for small tables

# Solution Components
## Power Subsystem:
- Convert wall power to usable power for controller, sensor, cleaning arm, and notification subsystems.

## Cleaning Arm Subsystem:
- Use track and motors to move arm down the table in order to clean and sanitize the table. Tentatively consists of a sprayers for cleaning solution, squeegee, and drying cloth. These are arranged to be used in the order during the cleaning cycle
- Will hide in housing when not in use, not affecting the usable width of the table
- Gear track will be flat against the underside of the tables
- Guide tracks will be almost flush against the table, taking up no more than 2 inches of legroom from the patrons.

## Sensor subsystem:
- Infrared break beam sensor to detect cutlery or other objects on table
- Passive infrared sensor to detect if people are present. And detect when patrons leave to start the cleaning process.
- Start button that patrons can press to start the cleaning process. If not then similar to automatic toilets the table will clean itself when it has sensed that patrons have left.

## Control subsystem
- We will use an ATMega328 microcontroller for the control logic
- It will use sensor data to determine if cleaning is safe and no people/cutlery are present.
- Will also control arms through their motion.
- Controls the notification system.
- Keeps track of the internal finite state machine.

## Notification Subsystem
LED’s to indicate status of the table - Low disinfectant, unable to clean, etc.
Small speaker to alert staff when entering warning state

## High level Cleaning Cycle Process
Sensing Sequence
Check if people are present: if no-move to 2, if yes-return to 1
Wait a short amount of time and move to 3
Check if people are present: if no-move to 4, if yes-return to 1
Move the cleaning arm away from the housing, across the table, scanning for large objects. If an object is encountered: if yes-move to 5, if no-begin cleaning cycle
Return to home and show status saying the table needs objects removed. Move to 1
Cleaning Cycle
Set the arm in the cleaning start position
Lower arm to cleaning height
Start the sprayers and begin moving arm toward home
As the arm moves back to home, sense for large objects in the way
If an object is encountered- stop the the arm and show an error status on the table, if no-continue cleaning
Once back at the housing, return to Sensing state

# Criterion for Success
- Completely clean and sanitize table
- Detect objects on the table and halt cleaning cycle if objects are present
- Detect people and do not cycle if people are present.
- Show table status as ready for use or other service needed.
- No impact to the usability of the table for customers.

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