CONSUMER ELECTRONICS
DSI Sense – Indoor Dry Skin Index Monitoring Device
Project Overview
Designed and developed a smart diagnostic device that continuously measures the Dry Skin Index (DSI) to estimate the hydration level of the skin’s outer layer. The device syncs data in real time to mobile apps and the cloud, offering actionable insights for better skincare and indoor air management.
HARDWARE | FIRMWARE | MOBILE/WEB APPS | EMS MANUFACTURING
Client Requirement & Objectives
Accurate DSI Monitoring
The device must accurately measure the Dry Skin Index using an onboard environmental sensor and transmit the data periodically to the server for analysis.
Multi-Protocol Communication
t should support both BLE and Wi-Fi protocols to ensure smooth connectivity with Android/iOS apps and data transfer to AWS servers via MQTT.
Provisioning & OTA Updates
Initial BLE pairing should allow Wi-Fi provisioning; once configured, the device must perform OTA firmware updates and securely upload sensor data to the cloud.
User-Friendly Data Visualization:
The mobile application should fetch DSI values from the cloud and present them as trends or insights in an intuitive, user-friendly format for the end user.
System Design & Build
Dual Connectivity Stack
Implemented a BLE-based onboarding system with secure Wi-Fi provisioning, followed by MQTT-based data sync to AWS IoT.
OTA & App Sync
Enabled firmware updates over-the-air post-initial BLE setup, with seamless integration into Android/iOS apps.
Sensor Integration
Integrated calibrated DSI sensors with adaptive polling intervals and filtering to maintain reading accuracy.
Cloud Architecture
Developed a lightweight MQTT protocol handler with retry and session persistence, and connected to AWS for scalable data storage and visualization.
Key Challenges & Solutions
Heat Dissipation in a Compact Form Factor
Wi-Fi modules generated heat that interfered with DSI readings. We redesigned the PCB and enclosure to improve ventilation and separated the sensor from hotspots.
Sensor Isolation:
Special PCB layout and firmware calibration routines were implemented to minimize noise and thermal drift around the sensor.
Low Power Optimization
Balanced real-time data needs with power consumption by optimizing BLE and Wi-Fi duty cycles and reducing sensor polling during inactivity.
OTA Reliability:
Ensured robust OTA processes with fallbacks and version rollbacks to handle interrupted firmware updates.
Project Tech Stack
Micron
Telit
Nordic
SEMTECH
IRIDIUM
Espressif
STM 32
u-blox
Bluetooth
Cloud
Android
iOS
React.js
Django
Client
The DSI Sense is the first sensor device + app that monitors the Dry Skin Index to help people moisturize their skin in a proactive, timely fashion. The Dry Skin Index is based on a thermodynamic property of water vapor that is calculated from both humidity and temperature.
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