K-Fee: The Connected Coffee Machine ☕️🤖
A web-controlled coffee brewing system that combines IoT hardware with full-stack development
🔗 View on Hackster.io
🔧 GitHub Repository
Project Overview
We reengineered a standard coffee machine into a smart brewing system controllable via web interface. Users can:
- Customize sugar levels (1-5 cubes)
- Select cup size (S/M/L)
- Create/save custom recipes
- Schedule automatic brewing
- Monitor ingredient levels in real-time
Homepage of the connected coffee machine web interface
Technical Breakdown 🛠️
Hardware Architecture
- Brain: Raspberry Pi 3B+ (MQTT broker/server) + ESP32 (sensor/motor control)
- Sensing Suite:
- VL53L0X time-of-flight sensors (ingredient level monitoring)
- Capacitive proximity sensor (cup detection)
- Water level sensor
- Actuation System:
- NEMA 14 stepper motors with custom 3D-printed augers
- L298N motor drivers
- Grove Relay for 230V kettle control
- Safety: Red LEGO-enclosed high voltage compartment
Software Stack
- Web Interface (Python/Flask):
- Recipe database (SQLite)
- Scheduled brewing system
- Real-time machine status dashboard
- MQTT Communication (Mosquitto):
- Website ↔ Raspberry Pi ↔ ESP32
- JSON payloads for brewing parameters
- Firmware (C++/Arduino):
- Sensor data acquisition
- Motor control algorithms
- Safety interlocks
Development Challenges 🧗
- High Voltage Handling: Safely controlling 230V kettle with ESP32
- Material Flow: Designing 3D-printed augers for consistent sugar/coffee dispensing
- Sensor Fusion: Combining multiple sensing modalities for reliable operation
- Real-time Sync: Ensuring <500ms latency between web request and machine start
Lessons Learned 🎓
- Team Collaboration: Coordinating between 4 developers across hardware/software
- Iterative Design: 7 versions of 3D-printed augers to prevent ingredient clumping
- Safety First: Implementing multiple failsafes for high-voltage components
- User Experience: Balancing technical complexity with intuitive web interface
Project Gallery 📸
Architecture overview showing MQTT communication flow
Team Insights 💡
“Well the coffee wasn’t that good, in fact there was too much sugar for not enough coffee, but it was a fun project to work on.”
Ready to brew?
👉 Full tutorial on Hackster.io
👨💻 Explore the codebase