Master the Internet of Things: Create Your Own Smart Greenhouse Model!

First, let's begin with an introduction to the system model:

The physical model is mainly divided into four parts:

Greenhouse Model;

Gas and Liquid Generation Devices;

System Control Circuit;

Greenhouse Monitoring Center;

1.Greenhouse Model

The greenhouse/shed model features artificial turf and plant models as decorations, with various sensors installed within the model. Water pipes are suspended with holes punctured for irrigation purposes, and a ventilation fan is installed on the left side.

2.Gas and Liquid Generation Devices

The gas generation device comprises three water pumps and three storage bottles. One of the water pumps is used to control the reaction between baking soda and water, which generates a large amount of CO2 stored in the bottle. Another water pump is responsible for drawing water from the storage bottle and delivering it to the water pipe to achieve a drip irrigation effect for watering plants. The last water pump also draws water and delivers it to the water pipe to create a spraying effect, which can be used for irrigating large areas of plants and firefighting.

3.System Control Circuit The hardware system

Based on the STM32 microcontroller, includes: the STM32 microcontroller minimum system board, power regulation circuit, multi-channel relay module, buzzer driver circuit, ESP8266 wireless network module, and various sensors such as flame sensor, temperature sensor, humidity sensor, and CO2 sensor.

Considering that making a PCB would incur costs, a handmade version was created instead. As a result, the wiring is quite messy and hasn't been organized, so please go easy on the criticism!

The circuit schematic and PCB diagrams are as follows:

4.Greenhouse Monitoring Center

The greenhouse monitoring client, designed using the Onenet platform's application editor, provides real-time updates displaying temperature, humidity, changes in temperature and humidity trends, flame alarms, working status of water pumps and ventilation fans, and whether leaf surfaces contain water. A mini development board is embedded into the system as the Internet of Things (IoT) hub, utilizing China Mobile's ONENET platform to upload data. This setup monitors various parameters of sensors within the greenhouse/greenhouse modules' operational status.

System Architecture Diagram:

Working Principle:

The system employs an STM32 microcontroller as the control chip to collect data from various sensors and execute corresponding processing tasks. By controlling relays, it drives the water pump, air pump, ventilation fan, and buzzer (and uploads data to a server for terminal viewing), ultimately achieving automated control of greenhouses.

Firstly, when the soil moisture in the greenhouse drops below 40% RH, the microcontroller activates the water pump to start spraying (drip irrigation) to adjust the soil moisture. When the CO2 concentration level in the greenhouse falls below 1000 PPM, the air pump starts generating CO2 to raise the concentration above 1000 PPM. The CO2 is generated through the reaction of baking soda with water, producing a large amount of CO2 stored in a gas storage bottle.

Secondly, the greenhouse is equipped with flame sensors. In the event of fire detection, the microcontroller triggers the buzzer alarm, activates the water pump to spray water, and drives the fan to ventilate.

Additionally, the monitoring and management center for the greenhouse is designed based on the China Mobile OneNet IoT platform. Using the ESP8266 module to connect to WiFi, the system uploads various sensor data (such as temperature and humidity) and operational status to the greenhouse monitoring management system. We can access this system via two methods: PC web client and mobile app.

Partial program