[Shenzhen University Electronic Competition] 32-bit microcontroller core board infrared temperature measurement rotating fan

We selected the STM32F103RCT6 microcontroller as the core controller and added an infrared sensor module, motor drive module, servo drive module and temperature and humidity sensor module to realize the fan's position recognition and temperature sensing functions.

The system architecture is as follows:

1. Controller module

The controller module is mainly composed of STM32F103RCT6 microcontroller. The microcontroller core board also includes independent button circuit, OLED display interface circuit, communication-download interface circuit and LED circuit.

1.1 LED circuit -------The LED circuit consists of two LEDs and two resistors. The LED circuit can indicate whether the program is running normally. For example, in the servo driver, the LED is on and off to initially judge whether the program is executed.

1.2 Communication-Download Interface Circuit ------- The core board is connected to the communication-download module through the XH-6P sub-socket. The PWR of the interface circuit will indicate whether the STM32 is successfully connected to the module. The interface circuit is powered by the communication-download module, and relies on the communication-download module to complete the task of downloading the computer program to STM32.

1.3 OLED interface circuit ------- The core board is connected to the OLED display through J7, and data can be displayed through the OLED display.

1.4 Independent button circuit ------- Each button is connected in parallel with a capacitor. When the button is pressed, the voltage of the STM32 microcontroller is low level. In programming, you can control the execution of function modules through buttons.

1.5 STM32 microcontroller circuit ------- This circuit includes STM32 microcontroller, filter circuit, reset circuit and startup mode selection circuit, which mainly controls all modules. The IO port of the microcontroller can also be used to connect functional modules other than the core board

The picture shows the STM32 architecture

2. Additional implementation functions

2.1. Infrared sensor module ------- We use the HC-SR501 infrared sensor module. The advantages of this module are that it does not emit any type of radiation, the device consumes very little power, has good concealment, is cheap, and works The voltage is consistent with the voltage provided by the core board. This kind of probe can detect human body radiation within a range of less than 120 degrees and a distance of 7 meters and output a high level, which in turn drives the steering module to change the direction of the fan.

2.2 Motor drive module ------- We use the L9110 motor drive module, which has strong anti-interference ability and large current drive capability. By measuring the temperature and humidity sensor, the L9110 controls the fan blade speed.

2.3 Servo drive module ------- We use the SG90 servo drive module. SG90 has a low operating voltage, is easy to operate, and is cheap. It has two categories: 90 degrees and 180 degrees, and the one we chose is the 180-degree SG90 servo. It relies on the recognition of the infrared sensor in our infrared temperature measurement fan to drive itself to the position of the person.

2.4 Temperature and humidity sensor module ------- We use the DHT11 temperature and humidity sensor module. The working voltage is 3-5.5V. This module has fast response and strong anti-interference ability. It can measure the temperature and humidity of the environment at the same time, thereby improving the accuracy of the measurement. In terms of function implementation, we use the data obtained by the sensor to adjust the rotation speed of the fan blades. The higher the temperature, the faster the fan blades rotate, and vice versa.