What is it?

This IoT controller combines a high-performance ESP32-C6 microcontroller with power relays, PWM outputs, and connectors for a wide range of sensors. Its wireless connectivity and programmability make it a versatile solution for automating tasks such as climate control in small and medium-sized greenhouses. Using this system, users can remotely monitor and adjust variables like temperature, humidity, light, and irrigation, increasing efficiency and improving productivity.

Why did you make it?

This controller was developed for use in indoor greenhouses for controlled agricultural production, allowing for highly controlled plant cultivation. To achieve a stable microclimate, it utilizes sensors, actuators, and control platforms capable of measuring environmental variables and controlling fans, pumps, heaters, or lighting. However, due to its versatility and modularity, it can be used in various applications depending on the user's specific requirements, based on the controller's features.

What makes it special?

The IoT controller system is flexible and can be adapted to different crops and greenhouse sizes. Some representative use cases are presented below.

Irrigation Automation:

• Soil moisture probes connected to analog inputs allow for moisture measurement in different pots or raised beds. When the moisture falls below a configurable threshold, the board activates a pump via one of the relays or PWM outputs to trigger a drip irrigation system. The irrigation schedule can be programmed from the mobile app and updated via Wi-Fi.

Ventilation and Temperature Control :

• Temperature and humidity sensors measure the air conditions inside the greenhouse. If the temperature exceeds the desired value, the system activates the fans and opens dampers via relays. On cold days, it can activate a heater connected to another relay output.

• The Wi-Fi interface allows for notifications to be sent when the temperature or humidity falls outside the preset ranges. A typical graph of the daily temperature and humidity evolution is shown below.

Lighting and Photoperiod Control:

• A relay or PWM output can be used to control LED grow lights. Photoperiod programming is done via the app, allowing you to adjust the duration of artificial light according to the plants' growth stage.

• Light sensors can measure natural light and automatically supplement with artificial light when necessary. CO₂ Concentration Monitoring and Ventilation • The addition of a CO₂ sensor allows you to monitor the carbon dioxide concentration inside. When the concentration is too high, fans are activated to refresh the air; when it is too low (preventing optimal photosynthesis), valves can be opened or CO₂ generators activated.

Integration with Cloud Platforms:

• Thanks to Wi-Fi connectivity, the microcontroller can be integrated with IoT platforms (AWS IoT, Azure IoT, Google Cloud IoT) or open-source services (Home Assistant, Node-RED). This allows for historical data storage, alarm creation, remote voice control, and real-time graph visualization.

Alerts and Predictive Maintenance:

• The system can send notifications to a smartphone when it detects faults, such as a pump without water or extreme temperatures, allowing for timely intervention. Recording environmental data helps identify trends and adjust ventilation or irrigation to prevent disease and optimize growth.

Specs

DC Power Input:

• Vin = 12V
• Imax = 2A

Protection:

• Fuses: 2.2A (Overcurrent)
• TVS Diodes: 16V (Over Voltage)
• Protection for reverse connection: 40V Schottky Barrier Rectifier

Buck and LDO:

• DC DC converter to 5V: High efficiency 92%
• LDO for control levels at 3V3 with TVS protection and isolated

Module:

• Module SoC that supports 2.4 GHz Wi-Fi 6 (802.11 ax), Bluetooth® 5 (LE), Zigbee and Thread (802.15.4)
• 4MB flash
• 23 GPIOs, rich set of peripherals
• On-board PCB antenna

CPU and On-Chip Memory:

• ESP32-C6 embedded, 32-bit RISC-V single-core microprocessor, up to 160 MHz
• 320 KB ROM
• 512 KB SRAM
• 16 KB Low-power (LP) SRAM

Dedicated inputs:

• Soil moisture sensors (x2)
• CO2 sensor (x1)
• Ambient temperature and humidity sensor (X1)
• Light sensor (X1)
• pH sensor (X1) (Optional)

Graphical User Interface:

• 2.4" TFT screen

Communication Buses:

• USB C
• I2C (Possibility of expanding sensors) / QWIC port
• SPI

Dedicated Outputs:

• 4 Relay Outputs: (Lamp, Extractor, Heater, Water Pump, Fertilizer Pump) - 110V-230V / 10A
• 2 Transistorized Outputs: (2 Pumps at 12V / 5A)