Eiwa Water Level Sensor
An IoT water level monitoring prototype designed to measure water usage in 20-liter bottles and transmit sensor data to a subscription-based Android application. The system enables predictive refill logistics by monitoring consumption levels and helping suppliers anticipate when customers need replacement bottles, reducing operational friction and improving service reliability.
Project Overview
Understanding the Project
The Goal
Develop a hardware-to-cloud integration system capable of monitoring water levels in real time and transmitting sensor data to a subscription-based mobile platform, enabling predictive refill scheduling and improving delivery efficiency.
The Challenge
Designing a reliable sensor integration capable of accurately measuring water levels and transmitting data efficiently to the backend infrastructure. The system needed to ensure stable communication between the IoT device and the mobile platform while supporting predictive refill logic for a subscription-based service model.
My Role
IoT & Backend Integration Developer responsible for sensor data acquisition, hardware-to-cloud communication, and API integration with the Android application. The mobile application was developed by a separate team.
Role
Firmware & Backend Integration
Timeline
2020
Platform
IoT · Firmware + API
Team
Cross-functional (Hardware + Software)
Screenshots
Visual Showcase
Mobile view consuming measurements from the backend API
Hardware prototype used for validation (electronics not developed by me)
Prototype installation used during real-world measurement tests
What I Built
- Designed and implemented the firmware algorithm to estimate liquid level from capacitive sensor readings.
- Implemented the firmware networking flow to send measurements to a backend REST API over WiFi (ESP8266).
- Defined the API contract required to register devices and store measurement history.
- Advised on database modeling to persist device metadata, measurement logs, and last-known status.
- Supported integration with a third-party Android application by aligning payload formats and endpoint behavior.
- Validated the prototype through measurement tests with satisfactory results under real usage conditions.
Tech Stack
Firmware
Backend
Mobile
Database
Architecture Design Decisions
These decisions were intentional to ensure the site feels professional, calm, and easy to navigate:
- Firmware-first approach to keep the measurement logic close to the sensor and reduce backend complexity
- Stable payload structure for long-term device compatibility and straightforward mobile consumption
- Database design focused on traceability: device metadata + time-series measurement history
- Clear separation of responsibilities between firmware delivery and mobile presentation layer
Results & Learnings
The prototype enabled automated water level monitoring and data synchronization with the Eiwa mobile platform, supporting a subscription-based service where customers never run out of water. By enabling predictive refill scheduling, the system reduces unnecessary store visits for heavy 20-liter bottles and improves logistical efficiency for suppliers.