A collection of typical MCU essay competition questions (Part 5)

Single chip microcomputer paper 9 water temperature control system

　　1. Mission

　　Design and make a water temperature automatic control system, the control object is 1 liter of clean water, the container is enamelware. The water temperature can be set manually within a certain range, and can be automatically controlled when the ambient temperature drops to keep the set temperature basically unchanged.

　　II. Requirements

　　1. Basic requirements

　　(1) The temperature setting range is 40～90℃, the minimum resolution is 1℃, and the calibration temperature is ≤1℃.

　　(2) When the ambient temperature drops (for example, by using an electric fan for cooling), the static error of temperature control is ≤1°C.

　　(3) Use a decimal digital tube to display the actual water temperature.

　　2. Development part

　　(1) Use appropriate control methods to reduce the system's adjustment time and overshoot when the set temperature changes suddenly (from 40°C to 60°C).

　　(2) The static error of temperature control is ≤0.2℃.

　　(3) When the set temperature changes suddenly (from 40°C to 60°C), a curve showing the change of water temperature over time will be automatically printed.

　　3. Rating opinions

　　Project score

　　Basic Requirements

　　Design and summary report: scheme design and demonstration, theoretical analysis and calculation, circuit diagram, test methods and data, analysis of test results 50

　　Actual production completion status 50

　　Play part

　　Reduce adjustment time and overshoot 20 Static error of temperature control ≤ 0.2℃ 10 Print curve function 10 Features and innovations 10

Microcontroller Paper 10 AM Radio

　　1. Mission

　　Use the components provided (with information) to build an AM radio receiver.

　　II. Requirements

　　1. Basic requirements

　　(1) Receiving frequency range: 540kHz～1600kHz;

　　(2) Tuning method: manual electric tuning;

　　(3) Output power: ≥100mW;

　　(4) Measure sensitivity, selectivity, image rejection ratio and electrical tuning characteristics (by direct injection of a signal generator); describe the test method, record the measured values ​​and draw the curves.

　　2. Development part

　　(1) Automatic and manual radio station search and storage function (can be achieved by using the provided phase-locked loop device or other methods);

　　(2) Number of preset radio stations: ≥ 10;

　　(3) Display the preset radio station number;

　　(4) Features and innovations (for example: improved performance indicators, single +3V power supply for the entire device, power saving, display of radio frequency, etc.).

　　3. Rating opinions

　　Project score

　　Basic Requirements

　　Design and summary report: scheme design and demonstration, theoretical analysis and calculation, circuit diagram, test method and test data, analysis of test results 50

　　Actual production completion status 50

　　Completed (1) 25 items Completed (2) 5 items Completed (3) 5 items Completed (4) 15 items

　　IV. Description

　　1. The electrical tuning characteristic refers to the relationship curve between the input signal and the control voltage of the varactor diode.

　　2. List of components provided (other components must be prepared by yourself)

　　(1) AM radio single chip integrated circuit (with low power amplifier), model: CX1600P/M;

　　(2) AM radio input loop coil and magnetic antenna;

　　(3) Varactor diode, model: SVC341;

　　(4) Local oscillator coil;

　　(5) Phase-locked frequency synthesizer integrated circuit for electronic tuning, model: LC7218 (optional);

　　(6) 7.2MHz crystal (optional).

　　3. Attach a report summary of no more than 400 words before the design report.