# Fifth Lichuang Electronic Design Competition #Universal infrared remote control watch

# Note: * is required.

[Please fill in during the registration stage↓]

* 1. Self/team introduction

We are sophomore undergraduate students from the School of Electronics and Information Engineering of Shenzhen University. Our members are mainly from three majors: electronic science and technology, microelectronics science and engineering, and communication engineering.

* 2. Briefly introduce the project

It is mainly an STM32F411CEU6 as the main control chip with attitude sensing, infrared input, and infrared output. It can store any input infrared signal, and then emit infrared rays to control various electrical equipment, and has the ability to measure current, voltage, resistance, and capacitance. The watch is a highly practical gadget for electronic engineers.

[Please fill in during the competition stage↓]

< br> * 1. Describe project details

Many people may have heard of and used universal remote controls, but most universal remote controls are used to directly copy the remote control of a type of TV or other electrical appliances. They are not very convenient to use and have limitations. Faced with various Such electrical appliances often require various types of universal remote controls to match them. Sometimes what many people need is a remote control that can copy any remote control signal at will, but such similar products are often not common. Some people say that mobile phones also Similar functions can be achieved, but the fact is that not every mobile phone has an infrared emission function, and mobile phones cannot receive infrared signals, so they cannot copy the input infrared signals. Using a microcontroller to make such a product is a solution. It can also be used to debug various infrared devices, such as infrared remote control cars or other homemade devices, as an integrated remote control. The reason why the multimeter function is added is that for an electronics major or electronics enthusiast, the multimeter is often used most when debugging circuit boards. However, the traditional multimeter is larger in size, and for these people, Measuring high voltage, large current, and sufficiently accurate resistance is often not the focus. The multimeter is mainly used to measure the continuity of the circuit. Simply measuring the resistance of the resistor and the capacitance or current of the capacitor are the most commonly used. This meter That's the point.

* 2. Describe the challenges faced by the project and the problems solved

Hardware parts:

(1) First of all, due to lack of experience during the hardware welding process, many chips or devices were connected to tin. This technical mistake slowed down the entire circuit board welding and debugging process. Later it was found that the tools used Since many 0402 packages are used on the circuit board, soldering with a blade soldering iron will inevitably be a bit bulky. Using an ordinary tip can solder these small package devices very well. The tin connection can be solved by using flux, etc. to improve.

(2) Due to design errors, it was not considered that the ACS712 outputs an alternating current, and the rectification and filtering circuit was not added to the circuit design. Therefore, the function of measuring current cannot be realized, and hardware problems cannot be improved by software optimization. Software part:

(1) Due to the internal design of other programs in the microcontroller, there are problems with accuracy and response when processing the infrared transmitting and receiving part of the program. To solve this problem, we use an external STC microcontroller to pre-burn the infrared receiving and decoding program through the serial port. Connecting STM32 is actually equivalent to an external module, so that infrared reception and transmission can be completed independently;

(2) In the actual programming process, due to the use of ST's standard library, there are certain bugs. For example, initializing GPIO and other peripherals in some memory locations will fail and the register address cannot be written. It is speculated that this is a problem with the optimization of the standard library. , only the initialization code of some peripherals can be changed to solve this problem.

(3) During the system task scheduling process, the timer interrupt time does not match correctly, causing a series of problems when the system is running.

* 3. Describe the key points involved in the hardware and software parts of the project

hardware:

(1) The voltage detection circuit mainly converts the external -15v~15v voltage through several voltage-limiting resistors into 0~3.3v according to KCL and KVL, and then collects it by the ADC chip;

(2) Resistance detection circuit, based on the simple principle of voltage division, connect the resistance to be measured in series with 1k and 1M ohm high-precision resistors through analog switches to measure the voltage division, thereby achieving accurate measurement of resistance values ​​in a large range;

(3) The capacitance detection circuit calculates the time constant based on the first-order zero-state response of the capacitor, and then calculates the capacitance value of the connected capacitor based on the series resistance;

(4) The infrared receiving and transmitting circuit uses an external STC microcontroller (a module~~~~), which is pre-burned with the infrared decoding program, and then communicates with the STM32 through the serial port to realize the decoding and modulation of the external input infrared signal;

software:

(1) Posture calculation algorithm to realize step counting, hand raising sensing, wrist turning sensing, and LCD virtual touch screen;

(2) Decoding and transmitting algorithms for different infrared signals, infrared signal storage algorithms, etc.;

(3) Resistance and capacitance measurement algorithm;

(4) Customized timer system task scheduling algorithm.

< br> * 4. Project material list display

See attachment

* 5. Upload project pictures

5.1. If the contest logo is not printed on the PCB, it will be deemed as giving up the participation.

5.2. Other pictures of the project

* 6. Demonstrate your project and record it as a video for uploading

6.1. Video upload contest official website

Video has been uploaded, see top

6.2. Video title and link at Station B

Title: The 5th Lichuang Electronic Design Competition: "Universal Remote Control Watch" Project-Function Demonstration & Performance Test

Link: https://www.bilibili.com/video/BV1354y1m7Tr < br> < br> Notes:

①: Video requirements: Please shoot horizontally, the resolution is no less than 1280×720, the format is Mp4/Mov, and the size of a single video is limited to 100M;

②: Video upload: Please upload to the official website of the competition and Station B ( www.bilibili.com ) simultaneously. The top 10 most popular projects at Station B will receive 1,000-5,000 yuan in cash rewards, and other uploaded projects will receive 100 yuan Lichuang Mall no-threshold coupons;

③: Video title: The 5th Lichuang Electronic Design Competition: {Project Name}-{Video Module Name};

For example, the 5th Lichuang Electronic Design Competition: "Autonomous Driving" Project - Team Introduction. ( http://www.bilibili.com ),

The top 10 most popular projects at Station B will receive cash rewards of 1,000-5,000 yuan, and other uploaded projects will receive 100 yuan Lichuang Mall no-threshold coupons;

www.bilibili.com, the top 10 most popular projects on station B will receive a cash reward of 1,000-5,000 yuan, and other uploaded projects will receive a 100 yuan Lichuang Mall no-threshold coupon < br> < br> < br> * 7. Whether it is released to the public for the first time.

7.1. Please indicate whether the project has been published or won awards before.

This is a new project completely developed by Lichuang EDA and has not been published in any other competition or platform.

7.2. If the project is optimized on the original basis, please explain the optimization part

1. Optimized the collection and numerical optimization of analog quantities and the algorithm of capacitance and resistance.

2. Optimize the PCB diagram, from the previous two-layer plywood design to the current single four-layer design

* 8. Please see the attachment for the open source documentation program~~~~

* 9. Please see the attachment for references.~

Click the link for more details: https://www.szlcsc.com/go/dsxq