Internet of Trays, Your Singapore Hawker Dream
By: Karisse Khoo
Tags: IoT, Charts, Data Driven, Sensors, Connectivity

Introducing Internet of Trays

So what makes our solution so unique?

Market solutions out there generally use RFID technology in order to gather tray return data. The nature of RFID allows for quick detection with the ability to take multiple readings at once so it doesn’t matter even if the trays are stacked.

However, not implementing the RFID system hawker-wide greatly dampens its effectiveness. Take for example, the following scenarios:

Not returning the trays to their designated RFID point would lead to underestimation of tray return rates The possibility of wear and tear or misplacing our RFID tray tags from washing Lack of resources to tag sufficient trays for data collection

Despite being a great solution, it fails to account for many blind spots thus we decided to proceed with a zone-based solution that would provide a better reflection of the tray return rate for a selected zone given the known constraints.

Our solution is founded on the following principles we have learnt in IoT:

Minimal deployment of sensors, use only what is needed. Easy to deploy and easily scalable. Relatively friendly and appealing aesthetics.

Architecture

Overview of Solution Architecture

Here is a high-level overview of our implementation, our group makes use of 3 different types of sensors in total. The RPI acts as a gateway to send data to our Mongo Database through WiFi connection. This data is then constantly being aggregated by an external EC2 server running on AWS which is then pulled by our Frontend Dashboard to display up-to-date information online.

Our Solution Set Up

Tray Return Rack

This setup comprises 2 Infrared (IR) sensors on each level of the Tray Return Rack.

By emitting an infrared light which returns the distance of the closest object obstructing its path, the IR sensor is able determine whenever a tray is present. By keeping track of the status of the tray return rack we would be able to track its utilization rate.

Table Set Up

As for the table’s setup, we have used 2 different sensors to ensure accurate data collection.

The round force sensors (RFS) informs us when a tray is placed on or removed from the table by detecting the change in pressure. While, the Proximity Infrared (PIR) sensor detects movement thus allowing us to check if the table is occupied. This allows us to see if patrons have left without returning their trays, essentially reflecting the tray return rate of a given table.

These have all been taped down and hidden from the customers making them as unobtrusive as possible. Above the RFS, we also placed boards with poster cut outs of the tray return campaign to encourage customers to return their trays.

Charts of Wisdom

The data received is displayed on our live dashboard so we can observe real-time changes in occupancy status of the tables and utilization of the tray return racks.

Moreover, there is an insights tab that automatically generates insights based on the data acquired which can provide the management with a direction to improving the tray return campaign. Read on to the next section to find out more!

Satisfying our stakeholders