Autonomous Lavatory Cleaning System

Arun Kumar C, Adithya Bharadwaj A, Balasubramanian R, Gowtham P
International Journal of Robotics and Automation (IJRA), Volume (6) : Issue (4) : 2015 65
Autonomous Lavatory Cleaning System
Arun Kumar C carunkumar_1994@yahoo.co.in
ECE Department
SSN College of Engineering
Chennai,600017,India
Adithya Bharadwaj A adibharadwaj13@gmail.com
ECE Department
Balasubramanian R b.ramesh07@live.com
ECE Department
Gowtham P gowthamp151@gmail.com
ECE Department
Abstract
The application of integrated robotics is becoming increasingly commonplace in day to day
applications. The idea presented in this paper seeks to provide a convenient and a hassle-free
means of cleaning public toilets whilst maintaining hygienic and sanitary standards. By using a
counter to record the number of times of usage, a line follower mechanism to guide the robot and
an RFID module to initiate the auto-flushing, the cleaning operation is fully automated and
requires low operational power. Furthermore, a robotic arm is part of the module, so as to
thoroughly clean the toilet bowl. Such a provision will curtail the role of manpower in maintenance
of public toilets to a great degree, and thus, serves as a win-win situation; a revolting objective is
accomplished with considerable ease.
Keywords: Line Follower, RFID Module, Auto-flushing, Low Operational Power, Robotic Arm.
1. INTRODUCTION
Urban sanitation is of prime importance in today’s society and there exist a number of obstacles
that need to be conquered. An easy to implement, yet effective method to facilitate the
preservation of hygienic standards would be a welcome idea, and help overcome the various
hurdles faced, such as human reluctance to engage in such a task. With this in mind, a viable idea
would be to design a robot that is fully automated in functioning is competent in performance.
Other considerations include ease of operation, power requirements and financial effectiveness.
Using a low power microcontroller and a simple yet adequate line follower robot, this idea is very
much practically realizable.
2. COMPARATIVE STUDY
In the present day scenario, there are a host of robots that aid us in domestic cleaning, which are
similar to the one proposed in this paper. For instance, the ‘Roomba’ by iRobot Corporation is a
home cleaner which incorporates vacuum cleaning techniques. While both the Roomba and the
Autonomous Lavatory Cleaning System(ALCS) share the same purpose of indoor cleaning, they
employ vastly different cleaning methods. Unlike the Roomba, ALCS has an approach that can be

termed as targeted. Hence it has a more explicit path which enables it to adopt a simpler traversal
algorithm. This reduction in complexity facilitates ALCS’ low power operation. The presence of RF
sensing technique also makes the cleaning action of ALCS more precise. The cleaning robot
presented in [N] is another one of the existing systems to perform the task under study. This robot
and ALCS share many design features. But the ALCS utilizes a cubicle selection algorithm which
eliminates redundancies and paves way for a more concentrated and efficient cleaning approach.
The operation of toilet cleaning being integrated into a mobile, self-operational robot is something
that has not been attempted before and is what makes this system unique. On the whole, by
improving upon existing concepts and by incorporating new features, the Automatic Lavatory
Cleaning System becomes a highly effective and utilitarian system.
3. RELATED WORKS
The concept of using a robot for the purpose of sanitation can draw many parallels to present day
technologies: robots are now used to serve a range of purposes, such as firefighting,
dishwashingand search and rescue missions, to name some. At present, the cleaning process is
entirely manual and not very productive. There exist very few methods similar to the one proposed.
4. IMPLEMENTATION
The robot is realized with the help of two microcontroller units (both MSP430).The first one
(referred to asMCU-1) is present on the robot and helps in the movement and cleaning action of
the robot. The second MCU (referred to asMCU-2) is interfaced with all the 4 cubicles and helps
keep track of the counters. To initiate the cleaning mechanism once the robot reaches the desired
cubicle, an RFID module is used. The robot is powered by a 12V DC battery and each of the
MCUs by independent 5V sources. The components are assembled as shown in the block
diagram in Figure1.
FIGURE 1:Block Diagram.

The working of this robot can be split into four modules as follows:
4.1 Module 1: Cubicle Selection
The cubicle to be cleaned is selected based on the frequency of usage of that cubicle. The number
of people visiting a particular cubicle is sensed by an infrared transmitter- receiver pair which is
placed at the doorway. Whenever a person enters a cubicle, he crosses this infrared sensor,
causing it to become low .In all such instances, the counter corresponding to that cubicle is
incremented. All such infrared sensors installed in each of the doorways are interfaced with an
MSP430 MCU [1][2]. The MCU-2 monitors the counter values and when one (or more) of the
counters becomes greater than or equal to 5,it sends the information regarding that cubicle to the
robot (MCU-1) via an RF transmission module. When more than one counter value becomes
greater than or equal to 5, then the cubicle with the largest count value is selected. If more than
one counter has the largest value, then one of those cubicles is selected at random.Afterthe
cubicle is selected,its counter value is reset to zero.
4.2 Module 2: Locomotion
The path from the starting point to each of the cubicles is laid as shown in Figure 2. Based on the
data received from MCU-2, the cubicle and its corresponding path are chosen.The robot uses line
follower technique [3] to travel in the selected path. The robot has three wheels, two of which are
connected to two 12-V DC motors (motor-1 and motor-2).The third wheel is a free wheel. These
DC motors are interfaced with MCU-1.By controlling the two motors,the robot can be made to
move forwards,backwards,left or right. The path is a black line of thickness 5cm.The robot has 7
infrared sensors on its face. When a sensor faces the black line,it sends a low output. Based on
the data received from all the seven sensors, the robot is calibrated and is prevented from
digressing. The robot senses the starting/ending point when all its seven sensors go low. Based
on the path chosen, the robot makes a call on what turn to take at intersections. For example, if
the path chosen is ‘Path II’, then the robot takes a left turn on the first intersection and a right turn
on the second. By this procedure, the robot reaches the desired cubicle.
FIGURE 2:Locomotion Sequence.

4.3 Module 3: Cleaning Action
Once the robot reaches the destination it initiates the cleaning sequence. An RFID sensing
antenna is affixed onto the robot; this senses the RFID tag placed on the toilet bowl, so as to
trigger timers T1 and T2 simultaneously, associated with microcontrollers MCU-1 and MCU-2
respectively. Once the timers are triggered, the cleaning procedure is initiated, as explained
below
• The toilet is automatically flushed with the help of a solenoid valve connected to the water
supply (interfaced with MCU-2)[4].
• The arm containing the brush is lowered with the help of a 12-V DC motor (motor-3).
• A cleaning liquid is dispensed into the walls of the closet and the axel containing the
brushes is rotated using motor 4(12V-DC) to perform cleaning. This action happens for 35
seconds.
• After 35 seconds, the brush is removed and the toilet is automatically flushed again[4].
• The brush is again lowered into the toilet and rotated for 25 seconds to perform thorough
cleaning.
• After 25 seconds, the brush is removed and the toilet is flushed again.
Upon the completion of the above six steps, the timer runs out indicating the end of the cleaning
action. The counter for this particular cubicle is made zero.
FIGURE 3:Cleaning Mechanism.
4.4 Module 4: Go Back and Repeat
After the cleaning action is completed, the robot turns around and traces its path back to its initial
position.
The above process is repeated for as long as the robot is active.
The systematic working of the above modules can be pictorially represented using a flowchart as
follows:

FIGURE 4:Flow of Control.

5. FUTURE ADVANCEMENTS
After the robot is implemented successfully, it can be improved by adding other cleaning modules
to focus on other parts of a bathroom, such as the wash basins and walls. This added feature will
serve to make the robot a commercial commodity and it can be sold as a wholesome package to
substitute manual cleaning of restrooms.
6. ADVANTAGES
i) Low power and cost effective modules:
The MSP 430 used consumes low power and is highly cost effective compared to the
higher end ATMEGA controllers used in Arduino platform.
ii) Highly automated system:
The human element in the system is minimized to the level of the sporadic cleaning
of the brushes and refilling of the cleaning liquid.
iii) Implementing RFID module is highly beneficial in a number of ways; it is cost
effective and does not require a line-of-sight communication, possesses high speeds
of operation and is best suited in tough environments.
7. CONCLUSION
The Autonomous Lavatory Cleaning System proposed can greatly eliminate the extent of manual
labor involved in the process of maintaining sanitary standards. With municipalities moving
towards solutions which can ameliorate the existing problems while being cost effective, this
system directly addresses actual concerns and seeks to provide an optimal solution. It can be
deployed for cleaning toilets in households, public restrooms and restrooms in malls, stadiums,
and supermarkets. Furthermore, it can be used for upholding standards of hygiene in trains and
airplanes, where it bears prime importance. The growing emphasis on smart cities and
environment friendly alternatives necessitate a technologically competent means of combating
the problem of cleaning restrooms and the Autonomous Lavatory Cleaning System seeks to
achieve exactly the same.
8. REFERENCES
[1] J.H.Davies.MSP430 Microcontroller Basics. Newnes: Butterworth-Heinemann Ltd, 2008,
pp. 146-382.
[2] P.D. Gasper, A.E. Santo, B. Ribeiro. “MSP430 microcontrollers essentials - A new approach
for embedded systems courses: Part 1 – Overview and tools,” in Proc. Education and
Research Conference (EDERC), 2010, pp. 66-70.
[3] M.E.Islam. Design and Fabrication of a Line Follower Robot.LAP LAMBERT Academic
Publishing, 2011, pp. 25-65.
[4] S.M. Ashiq. K. Karthikeyan, S. Karthikeyan (2013, Feb.). “Electrical Fabrication of Semi
Automated Pressurized Flushing System in Indian Railway Toilet.”International Journal of
Engineering and Advanced Technology (IJEAT). [On-line]. 2(3), pp. 778-998. Available:
http://www.ijeat.org/attachments/File/v2i3/C1077022313.pdf [Aug. 15, 2015].
[5] D. Kokvin, G.Sziebig, W.D. Solvang. “Design of a Robotic Arm for Automatic cleaning of
cargo containers”, presented at the 4th International Conference on Cognitive
Infocommunications (CogInfoCom),Budapest, Hungary, 2013.
[6] I. Matijevics. “Infrared Sensors Microcontroller Interface system for Mobile Robots”,
presented at the5th International Symposium on Intelligent Systems and Informatics,
Subotica, Hungary, 2007.

[7] P. Shukla. S.L. Shimi. (2014, Sept.). “Design Of Inspection And Cleaning Robot”International
Journal of Scientific Research Engineering & Technology (IJSRET). [On-line]. 3(6), pp. 970-
975. Available:http://www.ijsret.org/pdf/120795.pdf[Aug. 20, 2015].
[8] H. Park. S.Baek, S. Lee.“IR sensor array for mobile robot”, presented at the International
Conference onAdvanced Intelligent Mechatronics,Monterey, USA, 2005.
[9] C.H. King, T.L. Chen, A. Jain, C.C. Kemp. “Towards an Assistive Robot that Autonomously
Performs Bed Baths for Patient Hygiene”.
Internet:https://www.hsi.gatech.edu/hrl/pdf/iros10_auto_clean.pdf, Oct. 25, 2011 [Aug. 29,
2015].
[10]C. Hongakkaraphan. C. Beokhaimook. P. Nilkhet. “Investigation on Detection Accuracy of
RFID tags on back-to-back queuing objects”, presented at theAsian Conference on Defense
Technology,Hua Hin, Thailand, 2015.

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