Cocoa Monitor — IoT Fermentation & Drying System

A complete, simplified IoT monitoring system for tracking cocoa bean fermentation and drying using ESP8266 and ESP32 microcontrollers.

Overview

Cocoa Monitor logs environmental data and internal fermentation temperatures to a Google Sheet, enabling real-time fermentation tracking across multiple sensor nodes.

Fermentation Phase

• TEMP Node: Bean mass temperature profile (3× DS18B20 probes)

Drying Phase

• GREENHOUSE Node: Inside drying environment (DHT11)
• OUTSIDE Node: Outside reference environment (DHT11)

All nodes upload to a single Google Sheet via a shared Google Apps Script backend.

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Quick Start

Hardware

• 3× ESP32 Dev Boards
• 3× DS18B20 temperature probes (TEMP)
• 2× DHT11 sensors (GREENHOUSE, OUTSIDE)
• WiFi network (SSID: xxxxxxxxxxxxx)

Installation

1. Flash firmware from /firmware to each board (see guide)
2. Deploy Apps Script from /apps-script to Google Apps Script
3. Verify uploads within 5–10 minutes (data appears in Google Sheet)

See docs/COCOA_MONITOR_SIMPLIFIED_GUIDE.md for complete setup instructions.

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File Structure

cocoa-monitor/
├── firmware/                      # Arduino sketches (ready to flash)
│   ├── TEMP_DS18B20x3.ino         # NodeMCU ESP8266 (fermentation temps)
│   ├── GREENHOUSE_DHT11.ino       # ESP32 (inside greenhouse)
│   └── OUTSIDE_DHT11.ino          # ESP32 (outside environment)
├── apps-script/
│   └── AppScript_Simplified.gs    # Google Apps Script backend
├── docs/
│   └── COCOA_MONITOR_SIMPLIFIED_GUIDE.md  # Complete installation guide
└── README.md                      # This file

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Key Features

✅ 4 Independent Nodes — Fermentation environment + temps + drying (indoor/outdoor)
✅ Real-Time Logging — Automatic uploads every 5–30 minutes
✅ NTP Time Sync — Accurate UTC-4 (Trinidad) timestamps
✅ Error Handling — WiFi reconnection, sensor fault detection, fallback timestamps
✅ Simplified Code — All bloat removed, lean & focused

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System Architecture

Internet
   ▲
   │ HTTPS GET (Apps Script)
   │
┌──────────────────────────────┐
│   Google Sheets              │
│  (3 worksheets)              │
│  • TEMPERATURE               │
│  • GREENHOUSE                │
│  • OUTSIDE                   │
└──────────────────────────────┘
     ▲         ▲         ▲
     │         │         │
   [TEMP]    [GHSE]    [OUTSIDE]
  DS18B20x3  DHT11     DHT11
  ESP32   ESP32     ESP32

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Configuration

All nodes share the same WiFi and Apps Script URL:

WiFi SSID:       your info
WiFi Password:   your info
Timezone:        UTC-4 (Trinidad)
Apps Script URL: https://script.google.com/macros/s/your info/exec

Modify in each sketch before flashing.

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Google Sheet Details

Sheet ID: your info

Worksheets created automatically:

• TEMPERATURE — Timestamp, T1_Top_C, T2_Middle_C, T3_Bottom_C, Average_C
• GREENHOUSE — Timestamp, Temp_C, Humidity_%
• OUTSIDE — Timestamp, Temp_C, Humidity_%

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Troubleshooting

Device won't connect to WiFi

• Verify SSID and password match in sketch
• Check WiFi range and signal strength

DS18B20 reads -127°C

• Verify 4.7kΩ pull-up resistor between D2 and 3.3V
• Run address-scan sketch to get probe hex addresses
• Paste correct addresses into TEMP_DS18B20x3.ino

Data not appearing in Google Sheet

• Check serial monitor (115200 baud) for HTTP error codes
• Verify Apps Script URL is correct
• Ensure NTP time sync completes (wait 30 sec after boot)

Apps Script errors

• Do NOT create a new deployment after edits — edit in place
• Use "Manage Deployments" to refresh the existing URL
• Check Apps Script Execution Log for debug messages

See docs/COCOA_MONITOR_SIMPLIFIED_GUIDE.md for more troubleshooting.

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Upload Intervals

Node	Interval	Purpose
TEMP	60 min	Fermentation heat curve
GREENHOUSE	60 min	Drying progress (indoor)
OUTSIDE	60 min	Drying reference (outdoor)

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Libraries Required

For ESP32 (GREENHOUSE, OUTSIDE):

• WiFi (built-in)
• HTTPClient (built-in)
• DHT sensor library by Adafruit

Install via Arduino IDE Sketch → Include Library → Manage Libraries.

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Next Steps

1. Read the guide — docs/COCOA_MONITOR_SIMPLIFIED_GUIDE.md
2. Flash firmware to your 3 boards
3. Deploy Apps Script to Google Apps Script
4. Monitor uploads via serial monitor (115200 baud)
5. Create charts in Google Sheets to visualize fermentation data

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License

MIT License — see LICENSE file for details.

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Notes

• Remove test code before deployment — ensure READ_INTERVAL and UPLOAD_INTERVAL are production values
• Backup your Google Sheet — no version control, edits are permanent
• Check sensor baselines — DS18B20 probes are ±0.5°C accurate; no calibration needed

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Last Updated: July 2026
Version: 1.0 (Simplified)

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For questions or issues, refer to the complete guide in docs/.