Smart Toilet Signaling System

Technical Details/Project Implementation

Technology Overview/ System Operation

 With the application of smart sensors & mobile communication technology, the integrated Smart Toilet Signaling system can achieve remote status monitoring and automatic controlling for the public restrooms. Furthermore, three main modules will be involved in the system framework: data collection, data analysis, and feedback generation (shown in figure 1).

The “data collection” working group mainly comprises of three types of sensors including occupancy/vacancy sensor, ammonia sensor, and people counter. They are interconnected through wireless or cable networks integrated into the Internet, offers endless opportunities for tracking the service condition of washrooms from different floors.

For data analysis, it is necessary to have a central server to synthesize all the data gathered by the sensors. Besides, another vital function of the central server is generating charts and graphs reflecting some algorithms results. This should be done by the interfaces software installed inside. Finally, the server will send those appropriate feedback to the management and customer interfaces for their particular uses via the Internet.

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(Figure 1.: designed by Karlie)

Components Specifications

The whole operational model comprises a series of hardware, gateway, central server and interfaces software that performs mesh data collection, algorithms, and visualization. In the following, it will show all of the components that should be invested in practicing the Smart Toilet Signaling system.

Hardware:

IoT smart sensors are tangible devices that take input from the physical environment and they cooperate with compute resources to perform preassigned functions of the whole system (J. Hill, R. Szewcyzk, A. Woo, S. Hollar, D. Culler, and K. Pister, 2000). In order to cater different requirements of the data acquisition, we would like to adopt 3 types of sensors for monitoring the target washrooms:

1. Occupancy/Vacancy Sensor—PIR Motion Sensor (Lutron)

• Sensors with Passive Infrared (PIR) technology detects a change in temperature when someone enters. This type of sensors performs best in small, enclosed spaces with high levels of occupant movement (Longenderfer, J. E. & Pessina, M. W., 2014). For such reason, wireless PIR sensors are ultra-reliable to be ideally applied in toilets for detection of occupancy/vacancy.
• The PIR sensor will send the signal to the system and turn on the ceiling-mounted light bulb of that toilet once the user leaves. Then, the people can have an intuitive judgment to determine whether there are available cubicles.
• By considering the stability, we decided to choose Lutron as PIR sensors provider as their PIR sensors communicate via Clear Connect. RF technology, which operates on a low-frequency band (434 MHz) to avoid interference from other wireless devices (e.g. customers' smartphones).[pic 6]

(Picture Source: www.lutron.com/sensors)

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Features:

• 180° filed-of-view
• up to 30 ft x 30 ft major motion & 20 ft x 20 ft minor motion coverage
• high-low sensitivity adjustment

1. People Counter—Wi-Fi Networks

• Researchers at the University of California have found that Wi-Fi can count the number of people in a given area without smartphones, laptops and other devices. Surprisingly, a high degree of accuracy can be given by this method (Fernandez, S., 2015). Therefore, we can install a pair of Wi-Fi hardware (transmitter & receiver) at either end of a restroom to determine the number of people passing between them.

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• More specifically, people will mainly affect the power link of Wi-Fi in two ways: a. Attenuating the link signal when crossing, and b. Scattering the link signal when deviating. The intelligent processing of dips and boosts in the Wi-Fi signal can help the system accurately extract the number of people queuing up for toilets (see figure 2).  

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(figure 2. Wi-Fi signal strength variation in dBm )

1. Odor Sensor — Ammonia Sensor MQ135

• The purpose of ammonia sensor is to monitor the sanitary condition in each washroom and to help the staffs provide maintenance and repair correspondingly. By targeting ammonia gas and smell of waste in the washrooms, the Ammonia Sensors MQ135 can measure the odor concentration level. After that, the data will be transferred to the central server and notice the manager there is a destruction indication of the flushing system. [pic 10]

Mechanism:

•  Hydrogen will combine with oxygen and evaporates as water molecule when ammonia (NH3) and the smell of waste are passed over the sensors. Hence the conductivity of air will be increased by reducing the oxide layer. As a result, the calefaction of the heater inside the sensor indicates the detection of the target gas (Karthick, M., Sakthi, S. K. & Velmathi, G., 2014).

Software:[pic 11]

1. Windows Form Application — VISUAL STUDIO (VS)

• Microsoft Visual Studio(VS) is a tool for program development. By utilizing VS to set up a series of appropriate working principles for the entire system, we can provide remote-controllable washroom Windows Form Application (a virtual model working platform) for managers of the shopping malls. The following functions can be obtained from the platform:

• Calculate the usage rates of the washrooms & the service duration for of each toilet every time
• Examine whether a toilet is occupied & instantaneously display the service condition of each washroom from different floors
• Determine the destruction of a particular toilet & automatically reminder the cleaners to take action

1. ASP.NET

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ASP.NET is an open-source server-side web application framework for producing dynamic web pages. By writing a dynamic website through ASP.NET, mall customers can use their portable devices to find their nearest desirable washroom at that time. Specifically, the following information could be accessed via the website app:

• The closest and least-used washroom according to the user’s floor (floor levels would be represented as different colors)
• The usage & last-use time of each toilet
• The location of the target toilet

References:

Fernandez, S. (2015, June 8). Counting People With WiFi. UCSB, p.1.