Introduction...in brief

Our current project focuses on city-wide waste water management and autonomous man-hole monitoring system, that helps in leveraging the cost of traditional monitoring system through IoT and sensor amalgamation technique, but it still needs to fill the voids left in the current system.

Manholes are the entry points for maintenance of the sewer lines, hence by monitoring the status of the sewer lines from the manholes will help in doing preventive maintenance and can prevent a heck-lot of sanitary problems in the cities.

Goals that have been accomplished at our Research Lab

Our current solution equips the 'marked' manholes with sensors that can:

1. Measures the water/ sewerage level at particular sensor-equipped manhole.

2. Detect the status change in the manhole lid - whether the lid is present or absent, and if absent, is it a scheduled maintenance call or a theft ?

3. To provide a Sewerage/ Water SOS level at which an alarm shall be sent to the Command Centre.

"Initial Requirement: The Smart Manhole Sensor shall be a centralized sensor integrator with IP67 housing, and shall be fitted inside the manhole at the most suitable location. It shall communicate the real-time sensor data through the cellular/non-cellular (LPWA) network. It shall comprise of the following types of sensors :

1. An IP67 rated Ultrasonic Sensor which will periodically monitor the Water/ Sewerage Level flowing in the Sewer Line, and shall also report the historical data over a period of time. These Ultrasonic Sensors must have the capability of measuring liquid levels upto 400 cm which shall essentially cover the entire width of the drainage pipe and the height at which it is installed on the manhole above the drainage pipe.

2. A heavy duty passive actuator for detection of manhole cover state (open/close) change. A message shall be sent instantly when the manhole cover is opened or closed.

3. A Sensor Probe which will actuate an alarm if the Water/ Sewerage reaches the 'threshold-limit'."

To equip the manholes with sensors having the above functionality, it is necessary to deploy sensors throughout the sewer-line infrastructure. However, because of the need for dedicated circuits and power sources as well as sensors with wireless connections, batteries may need to be replaced, making the operating costs for each sensor expensive, and making it difficult to deploy sensors across a wide area.

Hence deterministic approach should be made on behalf of pre-analytics and cognitive approach for determining the exact locations and number of manholes where sensors should be installed, based on the analysis of the time required for water to flow from upstream pipes to downstream locations in accordance with land topography and the shape and length of sewer pipes, which makes it possible to track and predict the overall flow through a sewer system using only about one-third as many sensors(proven through our MARK_simulation-model).

Fundamentals for this Design Challenge(TODC) :

The RSL10Sense Board is the perfect candidate among the existing solutions in the market regarding things such as;

- Form-factor; optimised sensors and electronics layout with circular PCB, that makes it a perfect solution to wearable category.

- Connectivity; integrated with cutting-edge BLE5.0 which provides 4x capabilities in terms of broadcast-data, bandwidth and operating range.

- SensorMatrix; armed with multi-sensors, ever witnessed in such price range; aiding to easy integration in nearly every project one can think to build of.

- Zero-Carbon Footprint(Almost); With deep sleep modes and ultra low consumption, that can be powered through a coin-cell for 'eons' make it ideal for install'n'forget typical products similar to beacons that are passively geotagged for dev-maint. support.

- Easy Dev.nDebug Support; pairing it with it's official App, helps in unleashing the idea of efficient device-usage as well as developing various flavours of customised firmwares with distinct capabilities.

The prominent features from RSL10SENSE board, make it an (almost) perfect solution for our current problem. Hence, through this Design-Challenge, I would like to integrate it into the manhole covers, for detecting manhole cover theft situation(common & horrific at same time), utilizing the on-board 'sensor-loads' (IMU & ambience-sensing) and performing forecasted maintenance approach of manholes as well as mechanical stresses imposed on covers from regular traffic movement would prove to be more 'stealthier' than using 'limit-switch' based mechanical approach, which we have currently deployed for the PoC in conjunction with cellular network based on LTE-CatM1 within the manhole rigs for early detection of blockage and drain-flooding, but utilizing the non-cellular wireless approach for sensing the manhole-covers would definitely help to leverage down the associated costs.

WARNING: Hand Held Hazardous gas detection units must be duly carried by the maintenance personnel before undertaking maintenance of any manhole.

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