What is HigiBox?
The Intelligent Menstrual Care Dispenser — nicknamed HigiBox — is a smart device designed to improve access to menstrual hygiene products through automation, sensors, and connected technology.
Instead of being just a storage container, the device works as a smart companion system that provides hygienic product dispensing, stock monitoring, and cycle-aware notifications. By combining digital fabrication, electronics, and IoT connectivity, the project aims to make menstrual care more accessible, organized, and empowering.
Touchless, sensor-driven dispensing removes the need for manual contact — improving hygiene and ease of use.
Real-time stock sensing and weight measurement ensure you always know what's available inside the device.
A paired mobile app delivers refill alerts, cycle reminders, and supportive notifications via Bluetooth.
Designed entirely through Fab Academy skills — CNC milling, PCB design, 3D printing, and embedded programming — combining all weeks into a single cohesive product.
What It Does
Click each feature to explore how the system works. HigiBox is designed as a modular intelligent system — each feature can operate independently while contributing to the overall smart experience.
Touchless Interaction
A proximity sensor continuously monitors the area in front of the dispenser. When it detects a user's hand within range, the system activates automatically — no buttons, no contact required.
- Infrared proximity sensor (D6 pin)
- Sub-100ms response time
- Reduces cross-contamination
- Accessible for all users including those with mobility challenges
- Visual confirmation via LED strip (WS2812B)
Hand detected → Sensor fires → Controller reads D6 → Motor activates → LED confirms → Product dispensed
Multi-Product Compartments
The device contains three independent compartments, each controlled by a dedicated servo motor. Products are dispensed one at a time with precision, selected by the user or suggested by the app.
- Compartment A — Day pads (light flow)
- Compartment B — Night pads (heavy flow)
- Compartment C — Cramp relief pills (pain management during menstruation)
- Each servo independently addressable via PWM
- Mechanism tracked by motor encoder
Smart Stock Monitoring
Every compartment has an optical sensor that detects product presence. Additionally, a load cell with HX711 amplifier measures the total weight of remaining stock for precise quantity estimation.
- 3× optical sensors for per-compartment status
- Load cell on A0 for weight-based counting
- Low-stock threshold alerts (configurable)
- Stock data pushed to app via Bluetooth
- Historical usage analytics
Supportive Notifications
HigiBox is more than a dispenser — it's a cycle companion. The connected mobile app provides information, alerts, and support tailored to the user's needs.
- Refill alerts when stock is below threshold
- Product availability status per compartment
- Cycle-related reminders and suggestions
- Motivational and supportive messages
- Usage history and patterns
XIAO nRF52840 Controller
The brain of HigiBox is the compact XIAO nRF52840 — chosen for its built-in wireless connectivity, powerful processing, and tiny form factor that fits perfectly within the device housing.
- Built-in Bluetooth 5.0 + BLE — ultra-low power wireless
- Programmable via Arduino IDE
- USB-C charging and programming
- No external communication modules required
- Ultra-low power consumption for long battery life
stock_status: "low"
⚙️ How It Works — System Flow
Click each step to see what happens inside HigiBox during a single dispense cycle.
🤚 Step 1 — Hand Detection
- IR proximity sensor on pin D6 continuously scans
- When a hand enters range (<15 cm), sensor output changes state
- nRF52840 interrupt fires within milliseconds
- LED strip pulses rose to signal system activation
🧠 Step 2 — Controller Decision
- Microcontroller checks which compartments have stock
- Optical sensors confirm product presence per slot
- LCD display shows available product options
- Default: dispenses from highest-priority compartment with stock
⚙️ Step 3 — Dispensing
- Servo motor on selected compartment (D9 or D10) activates via PWM
- DC motor drives main mechanical movement
- Motor encoder confirms dispense completed correctly
- Load cell reads new weight to update stock count
📡 Step 4 — Reporting
- XIAO nRF52840 sends updated stock data via Bluetooth BLE
- Mobile app receives product type, quantity remaining, timestamp
- If stock crosses low threshold, push notification sent automatically
- Data logged for usage history and cycle patterns
Components & Electronics
Bluetooth 5.0 + BLE — ultra-low power wireless communication, no external module needed.
21mm × 17.5mm footprint — ideal for embedding in a small device housing.
Fully programmable with the standard Arduino ecosystem and nRF52840 libraries.
Modern USB-C connector for power and programming. No extra programmer needed.
🔌 All Hardware Components
📋 Component Pin Mapping
Digital Sensors
| Sensor | Qty | Function | Pin |
|---|---|---|---|
| IR / Proximity Sensor | 1 | Detect hand | D6 |
| Optical Sensors | 3 | Detect stock level | Digital header |
| Power Button | 1 | Turn device on/off | D7 |
| Motor Encoder | 1 | Track mechanism | Digital header |
Analog Sensor
| Sensor | Qty | Function | Pin |
|---|---|---|---|
| Load Cell (HX711) | 1 | Measure product weight | A0 |
Actuators & Outputs
| Component | Qty | Interface | Pin |
|---|---|---|---|
| Servo Motors | 3 | PWM | D9, D10 |
| DC Motor | 1 | Motor driver | External |
| LCD Display | 1 | I2C | SDA, SCL |
| LED Strip | 1 | Digital | Header |
| Status LED | 1 | Digital | D8 |
Circuit Board Strategy
The PCB was redesigned to simplify routing and improve manufacturability. Instead of integrating every component directly on the board, the design uses external headers for sensors and actuators — reducing trace crossings and making the system more modular.
Clean power rails for 3.3V logic and 5V motor supply, with proper decoupling.
On-board indicator for system state — powered, connected, error conditions.
All sensors and actuators connect via header pins — replaceable and serviceable.
Dedicated power button footprint on D7 for clean on/off control.
🔌 Interactive Pin Map
Hover each pin row to highlight. The bar shows relative signal complexity.
📊 Pin Summary
| Pin Type | Quantity | Used For |
|---|---|---|
| Digital Pins | 4–5 | Sensors, button, LED |
| Analog Pins | 1 | Load cell / weight |
| PWM Pins | 2 | Servo motors |
| I2C Pins | 2 | LCD display |
| Power Pins | Multiple | 3.3V, 5V, GND rails |
The key design decision was to move away from an all-in-one PCB toward a hub-and-spoke model. The main board handles power, the microcontroller, and essential I/O. All sensors, actuators, and outputs connect via labeled header pins.
This choice was driven by three priorities:
- Repairability — any sensor can be replaced without reflowing the board
- Routing simplicity — fewer crossings mean fewer vias and less signal noise
- Iterability — hardware can be upgraded compartment-by-compartment
Connected Companion App
The HigiBox app is the user's window into their dispenser. It connects over Bluetooth to the XIAO nRF52840, receiving real-time stock data and sending configuration updates. The app interface is designed to be calm, supportive, and informative.
App preview mockup
Push notifications when any compartment drops below the configured threshold. Never run out unexpectedly again.
Sync with cycle tracking for proactive product suggestions — ensures the right products are stocked at the right time.
Calm, motivational, and informative messages. The app is designed to feel like a caring companion, not a clinical tool.