This is an example of a basic "Weather Station using STM32 with ThingSpeak IoT." Powered by STM32 ARM Cortex (Blue Pill), this system detects environmental parameters like as temperature, humidity, and soil moisture. This example is a "Weather Station using STM32 with ThingSpeak IoT." The DHT11 is a temperature and humidity sensor that, as the name suggests, is used to measure the atmospheric temperature and humidity in a specific environment or in a confined closed space. A soil moisture sensor, on the other hand, is used to measure the level of soil moisture on the earth. Both of these sensors are used in conjunction with one another.

Now let's have a look at how to interface the widely used DHT11 temperature, humidity, and soil moisture sensors with the STM32 microcontroller by utilizing the Arduino IDE. The block diagram for this process is shown below. Microcontroller manufacturer ST Microelectronics' STM32F103C8T6 is included on the Blue Pill development board, which is also known as the STM32. This information is provided for individuals who are unfamiliar with the STM32. It is a 32-bit ARM Cortex M3 controller that features a high clock frequency and is designed to be used in high-speed applications that have power constraints. Construction & Working principle

1. STM32 (Blue Pill) (Blue Pill) 2. DHT11 Sensor 3. Soil Moisture Sensor 4. ESP8266 WiFi Module 5. 16X2 LCD Display The next section provides a full description of each element.

The temperature and humidity can both be measured with the help of the DHT11 sensor. A specific in-built NTC is included in the sensor so that temperature may be

accurately measured. It is equipped with an 8-bit microprocessor that will send the current temperature and humidity levels out as serial data via the one-wire protocol. This indicates that the sensor has only one data pin through which both the temperature and humidity values may be read, hence conserving pins on the microcontroller side of the equation. Additionally, the sensor is factory calibrated, making it simple to link with various other types of microcontrollers.

The amount of water that is contained within the soil is what is known as the moisture content of the soil. This can be determined by employing a soil moisture sensor, which consists of two conducting probes that function as a probe and is capable of measuring the soil's moisture content. The difference in resistance that occurs between the two conducting plates allows it to calculate the amount of moisture that is present in the soil. The quantity of moisture that is present in the soil has an inverse relationship with the amount of resistance that is there between the two conducting plates.

The ESP8266 wifi module is an inexpensive standalone wireless transceiver that can be utilized for the construction of endpoint Internet of Things applications. The embedded programs can now have internet connectivity thanks to the ESP8266 wifi module. The TCP/UDP communication protocol is utilized in order to establish a connection with the server or client. A series of AT commands must be entered into the microcontroller in order for it to be able to communicate with the ESP8266 wifi module. Using a UART with a predetermined Baud rate, the microcontroller is able to connect with the ESP8266-01 wifi module (Default 115200)

The actual appearance of the Blue Pill Controller is depicted in the following figure (Figure 5). When compared to the official Arduino boards, these boards are available at a fraction of the cost while also having open-source hardware. The microcontroller that sits atop it is a STMicroelectronics STM32F103C8T6, if you were curious. In addition to the microcontroller, the board contains two crystal oscillators: one with a frequency of 8 MHz and the other with a frequency of 32 kHz. Both of these crystals

have the capability of driving the on-board real-time clock (Real Time Clock). Because of this, the microcontroller can function in deep sleep states, making it an excellent choice for use in applications that are powered by batteries.

The operation of the project is based on the continuous measurement of the weather monitoring parameters, the display of those parameters on a 16x2 LCD display, and the uploading of those parameters into a cloud platform. Temperature, humidity, and soil moisture values are some of the weather monitoring parameters that will be displayed. In this instance, I am utilizing the ThingSpeak IoT Platform in order to save the data in a setting that is real-time. The power supply for the project must be 5V for the STM32, which is also referred to as the Blue Pill Development Board. 3.3V~3.6V for ESP8266 Wi-Fi Module. Here, I simply used a potential divider circuit to convert 5V to 3.6V. The diodes D3, D4, and a 1K ohm resistor are linked in series, and the cutin voltage for each silicon diode is 0.7V. Because I am connecting these two diodes in series, the overall voltage will be 1.4V less than 5V, which will be 3.6V.