Add project page for Artem Lebedev

website/versioned_docs/version-fils_en/project/2026/artem.lebedev/index.md

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+# Ali coffee
+Coffee vending machine with drinks selection options, based on ESP-32-C6 chip.
+
+:::info
+
+**Author:** Artem Lebedev (group 1221EB, FILS) \
+**GitHub Project Link:** [Ali coffee](https://github.com/UPB-PMRust-Students/fils-project-2026-artemlebedev)
+
+:::
+
+## Description
+
+This project is a coffee vending machine capable of creating a variety of coffee drinks using a gravity- and time-based dispenser of hot water and instant coffee. To implement this idea, we'll use a solenoid valve for the water tank, a servo motor with a flap for the coffee container, drink selection buttons, and a host of additional features: an LCD screen displaying the brewing process and water level, a buzzer to notify when the coffee is ready, and a float sensor to indicate when the water level is low. At the core of all these devices will be an ESP32-C6 chip; the enclosure will be a wooden T-shaped structure.
+
+## Motivation
+
+My desire to build a coffee machine, rather than any other device, is easy to explain – I'm a big fan of this aromatic drink, and if I'm going to do anything, it's going to be something I personally wouldn't shy away from using. Of course, my design is a far cry from a professional coffee machine, but at the same time, I think it will provide worthy competition to the machines dotted around campus.
+
+## Architecture
+
+The system is organized into three functional layers:
+
+**Input Layer**
+- Three tactile push buttons select the drink mode: Espresso, Double Espresso, or Americano.
+- A float switch liquid level sensor monitors the water tank and signals when it is empty.
+
+**Control Layer**
+- The ESP32-C6 SuperMini runs the main async task loop via Embassy.
+- On button press, a mode-specific timing profile is selected, and serving coffee and water for the correct duration starts.
+- The water sensor is polled continuously; if the tank is empty, dispensing is blocked and the display shows a warning.
+
+**Output Layer**
+- A 12V solenoid valve (normally closed) controls water flow from the tank to the cup, driven by an IRF540N MOSFET with a 100Ω gate resistor.
+- A servo motor (SG90) opens and closes a mechanical gate on the coffee powder container.
+- An SSD1306 OLED display (0.96", I2C) shows brewing status and warnings.
+
+All components share a common ground. The 12V rail powers the solenoid valve and is supplied by an external 12V 2A DC adapter. The ESP32-C6 is powered via USB.
+
+## Diagram
+![Ali_coffee_schematics](ali_coffee_schematics.webp)
+
+## Log
+
+### Week 5 - 11 May 
+
+### Week 12 - 18 May
+
+### Week 19 - 25 May
+
+## Hardware
+
+The system is built around the ESP32-C6 SuperMini microcontroller, which manages all inputs and outputs over GPIO, PWM (LEDC), and I2C. Two food-grade plastic containers (1–2L) serve as the water and coffee powder tanks, each mounted above the dispensing point to allow gravity-fed flow.
+
+Water flow is controlled by a 12V normally-closed solenoid valve. When the ESP32-C6 pulls the MOSFET gate high, the valve opens and hot water flows through a silicone tube into the cup. The MOSFET (IRF540N) is connected with a 100Ω resistor on the gate to limit switching transients.
+
+Coffee powder is dispensed through a mechanical gate controlled by the SG90 servo. At rest, the gate is closed. When activated, the servo rotates 90° to open the gate, powder falls by gravity, and the servo returns to close it after the timed duration.
+
+### Pin Connections
+
+| ESP32-C6 GPIO | Function | Connected To |
+|---|---|---|
+| GPIO2 | Button – Espresso | Tactile button → GND |
+| GPIO3 | Button – Double Espresso | Tactile button → GND |
+| GPIO4 | Button – Americano | Tactile button → GND |
+| GPIO5 | Solenoid valve control | IRF540N Gate (via 100Ω) |
+| GPIO6 | I2C SCL | SSD1306 SCL |
+| GPIO7 | I2C SDA | SSD1306 SDA |
+| GPIO8 | Servo PWM (LEDC) | SG90 signal wire |
+| GPIO9 | Water level sensor | Float switch → GND |
+| 3.3V | Power | SSD1306 VCC, SG90 VCC, Float switch |
+| GND | Common ground | All GND rails |
+
+### Schematics
+
+
+## Bill of Materials
+
+| Device | Usage | Price |
+|---|---|---|
+| ESP32-C6 | Main microcontroller | 50 RON |
+| Solenoid Valve 12V N/C | Water flow control | 25 RON |
+| IRF540N MOSFET | Solenoid valve driver | 2.5 RON |
+| Resistor 100Ω | Gate resistor for MOSFET | 0.5 RON |
+| Servo SG90 | Coffee powder gate control | 13.5 RON |
+| OLED SSD1306 0.96" I2C | Status display | 10 RON |
+| Float Switch Liquid Level Sensor | Water tank monitoring | 25 RON |
+| Food-grade plastic container 1–2L (×2) | Water and coffee powder tanks | 30 RON |
+| Silicone tube (thermoresistant) | Water delivery from tank to cup | 10 RON |
+| Hose barb fitting | Tank outlet connector | 5 RON |
+| Tactile push buttons (×3) | Mode selection | 5 RON |
+| Breadboard 830 points | Prototyping platform | 10 RON |
+| Dupont jumper wires (M-M, M-F set) | Component connections | 10 RON |
+| DC barrel jack 5.5mm | Power supply connector | 2.5 RON |
+| 12V 2A DC power adapter | Powers solenoid valve | 20 RON |
+| **TOTAL** | | **220 RON** |
+
+***
+
+## Software
+
+| Library | Description | Usage |
+|---|---|---|
+| `esp-hal` | Hardware Abstraction Layer for ESP32-C6 | GPIO, LEDC PWM, I2C peripheral control |
+| `esp-hal-embassy` | Embassy runtime adapter for ESP32 | Enables async task execution on ESP32-C6 |
+| `embassy-executor` | Async task executor | Runs concurrent tasks: buttons, dispensing, display |
+| `embassy-time` | Async time utilities | `Timer::after()` for precise dispensing durations |
+| `embedded-hal` | Hardware abstraction traits | Standard interface for GPIO and PWM |
+| `embedded-hal-async` | Async hardware abstraction traits | `wait_for_falling_edge()` for button and sensor input |
+| `ssd1306` | SSD1306 OLED display driver | Renders status messages on the 0.96" display |
+| `embedded-graphics` | 2D graphics primitives | Text rendering on the OLED display |
+| `esp-backtrace` | Panic handler with serial output | Debugging — prints panic traces over UART |
+| `esp-println` | `println!` macro over UART | Logging timing and sensor values during development |