Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 27 | Kombucha Fermentation Control System |
Edwin Xiao John Puthiaparambil Rudy Beauchesne |
Haocheng Bill Yang | design_document1.pdf proposal1.pdf |
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| # Kombucha Fermentation Control System Team Members: - Rudy Beauchesne (rudyb2) - John Puthiaparambil (jtp7) - Edwin Xiao (edwinyx2) # Problem Home kombucha brewing is becoming increasingly popular, but most options fall into two extremes: expensive commercial systems with automated control, or low-cost DIY methods that depend on frequent manual checks and guesswork. As a result, home brews are often inconsistent from batch to batch, with fermentation running too slow or too fast, acidity drifting outside the desired range, or the process stalling without clear feedback. This unpredictability can lead to inconsistent flavor and, in the worst case, failed or spoiled batches. There is a need for a low-cost, repeatable kombucha brewing system that continuously monitors key conditions like temperature and pH and provides clear, reliable feedback with minimal user intervention. # Solution We propose a low-cost, closed-loop kombucha brewing system designed to make home fermentation more consistent and repeatable. A microcontroller on a custom PCB continuously reads temperature, pH, RGB color, ultrasonic liquid level, and pressure sensors to track fermentation conditions and progress. Using these measurements, the system controls a heating pad to regulate temperature and peristaltic pumps to add fresh tea or remove liquid as needed based on user-defined targets. If feasible within budget, the system will also include a small optional aeration pump (air pump + sterile filter) for primary fermentation to provide controlled aeration during primary fermentation. A companion companion app dashboard (web-based) displays real-time status and logs trends over time so users can monitor brewing without constant manual checking. # Solution Components Subsystem 1: Fermentation Monitoring & Control This subsystem monitors the primary fermentation conditions and regulates temperature to keep the brew in a stable range. Functionality: - Continuously measure temperature, pH, and color trends during F1 - Drive a heating pad to maintain a user-defined temperature setpoint and control pumps for automated liquid handling - Send sensor data to the main controller for closed-loop control and logging Sensors / Components: - Temperature sensor: DS18B20 - Ultrasonic liquid-level sensor: HC-SR04 measures the brew height/volume to detect evaporation and prevent overfilling/underfilling during pump-based tea additions or liquid removal - pH Sensor: Analog pH probe + signal conditioning (PH-4502C module or equivalent front-end) - RGB Color Sensor: TCS34725 - Heating Element: Resistive heating pad controlled via MOSFET - Peristaltic pump(s): 12 V peristaltic pump (food-safe tubing) - Microcontroller: ESP32 Subsystem 2: Fermentation State & Safety Monitoring This subsystem monitors secondary fermentation indicators and system safety. Functionality: - Measure internal pressure buildup during fermentation - Detect abnormal fermentation conditions (overpressure or stalled fermentation) - Provide safety cutoffs and alerts if thresholds are exceeded Sensors / Components: - Pressure Sensor: MPX5700AP or equivalent pressure transducer - Signal Conditioning Circuit: Instrumentation amplifier and filtering - Safety Cutoff: Relay or solid-state switch for heater disable - Status Indicators: LEDs for system state and fault indication Subsystem 3: Data Logging & Web Interface This subsystem provides real-time data logging and user visibility through a web-based dashboard. Functionality: - Transmit sensor data (temperature, pH, color, pressure) to a web server - Log historical fermentation data for later analysis - Display real-time plots and system status via a browser-based interface Sensors / Components: - Wireless Interface: ESP32 integrated Wi-Fi - Backend: Lightweight web server or cloud-hosted database (e.g., HTTP/MQTT-based logging) - Frontend: Web dashboard displaying time-series sensor data and system state Subsystem 4: Power Management This subsystem provides regulated and reliable power to all system components. Functionality: - Supply 12 V power to the heating pad and pumps - Step down 12 V to 3.3 V for logic and sensors - Isolate high-power and low-power domains for safety and noise reduction Sensors / Components: - Power Source: 12 V wall adapter - Regulation: DC-DC buck converter (12 V → 3.3 V) - Loads: Heating pad, pumps, ESP32, and sensors Criterion For Success: - Maintain fermentation temperature within ±1°C of the target setpoint for a continuous 48-hour period - Measure pH with ≥0.1 pH resolution and maintain ±0.2 pH accuracy after calibration - Detect and log measurable color changes correlated with fermentation progression - Maintain safe operating pressure below a defined threshold and trigger a shutdown if exceeded - For the final demo, we will start from a deliberately off-condition brew (ice-cooled and pH shifted away from target) and show the system autonomously returning temperature and pH to a reasonable kombucha range using the heating pad and peristaltic pumps while logging and plotting all sensor trends live in the app This project involves significant circuit-level hardware design, including sensor signal conditioning, power management, actuator control, and embedded system integration. The scope and complexity are appropriate for a multi-person team and align with the course requirements. |
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