Custom IoT Device
Purpose-built wearable device based on the ESP32-S3 platform with premium biometric sensors for real-time fitness tracking, heart rate monitoring, and seamless app integration.
Processor
ESP32-S3
Dual-Core @ 240 MHz
Biometrics
MAX30102
HR + SpO2 Sensor
Motion
QMI8658
6-Axis IMU
Display
1.69" LCD
240x280 Touch
Software innovations that make the hardware truly unique.
Secure on-device key storage turns your watch into a crypto hardware wallet for signing AERO transactions.
Vibration patterns for rep validation, achievements, and workout cues without looking at screen.
Cadence-based classification using Tudor-Locke research — idle, slow walk, normal walk, brisk walk, jogging, running with MET values.
Over-the-air firmware updates for new features and improvements.
LVGL-powered animated watch faces and gamified visual feedback.
Real-time biometric data streaming over Bluetooth Low Energy.
Update Rate
Biometric data refresh
Latency
End-to-end delay
Connection
Auto-reconnect enabled
Power
BLE 5.0 optimized
Cadence-based classification using Tudor-Locke et al. (2018) walking cadence research.
| Activity | Cadence (SPM) | MET Value |
|---|---|---|
| Idle/Stationary | 0 - 14 | 1.3 |
| Slow Walk | 15 - 79 | 2.8 |
| Normal Walk | 80 - 99 | 3.5 |
| Brisk Walk | 100 - 119 | 4.3 |
| Jogging | 120 - 149 | 7.0 |
| Running | 150+ | 9.8 |
// Calorie Estimation (Ainsworth Compendium 2011)
Calories/min = MET × Weight(kg) × 3.5 / 200
ESP32-S3 acts as a hardware crypto wallet — private keys never leave the device.
Key Generation
BIP-39 mnemonic → BIP-32 seed → secp256k1
Address
Public key → Keccak-256 → last 20 bytes
Storage
AES-256-CBC encrypted in ESP32 NVS flash
PIN Protection
PBKDF2 (10K iterations), 5-attempt lockout
Signing
Decrypt key in RAM → sign → immediately wipe
Signing Flow
1. App sends 32-byte TX hash via BLE
2. Watch displays sign request on screen
3. User approves via gesture or button
4. PIN-derived key decrypts private key in RAM
5. ECDSA sign (secp256k1) + compute recovery ID (v=27+recid)
6. Private key wiped from RAM immediately
7. 65-byte signature (r + s + v) sent back via BLE
8. tx_count incremented and persisted
Hardware Implemented
Watch firmware, BLE communication, hardware wallet, and activity detection functional