A collection of typical MCU essay competition questions (Part 3)

Single chip microcomputer paper five simple radio remote control system

1. Mission

Design and build radio remote control transmitters and receivers.

1. Radio remote control transmitter

2. Radio remote control receiver

II. Requirements

1. Basic requirements

(1) Operating frequency: fo = Select any frequency from 6 to 10 MHz.

(2) Modulation method: AM, FM or FSK...select any one.

(3) Output power: not more than 20mW (on standard 75Ω dummy load).

(4) Remote control objects: 8. The controlled devices are represented by LEDs, which light up to indicate operation.

(5) The distance between the receiver and the transmitter should be no less than 10m.

2. Development part

(1) One of the 8-channel devices is a light. The brightness of the light is remotely controlled by commands. The brightness is divided into 8 levels and the level is displayed by a digital tube.

(2) Under a certain transmission power (no more than 20mW), try to increase the receiving distance.

(3) Add channel anti-interference measures.

(4) Reduce power consumption as much as possible.

Note: Ready-made transmitters and receivers cannot be used.

III. Scoring Opinions》Basic requirements for project scoring Design and summary report: scheme design and demonstration, theoretical calculation and analysis, circuit diagram, test methods and data, result analysis 50 Actual production completion 50 Partial completion of item (1) 12 Completed item (2) 8 Completed item (3) 5 Completed item (4) 5 Features and innovation 20

MCU Paper 6 Simple Resistance, Capacitance and Inductance Tester

1. Mission

Design and build a resistance, capacitance and inductance parameter tester with digital display

II. Requirements

1. Basic requirements

(1) Measurement range: resistance 100Ω～1MΩ; capacitance 100pF～10000pF; inductance 100μH～10mH.

(2) Measurement accuracy: ±5%.

(3) Make a 4-digit digital tube display to show the measured value, and use light-emitting diodes to indicate the type and unit of the measured component.

2. Development part

(1) Expand the measurement range.

(2) Improve measurement accuracy.

(3) Automatic switching of measuring range.

3. Rating opinions

Project scoring basic requirements Design and summary report: scheme design and demonstration, theoretical calculation and analysis, circuit diagram, test method and data, result analysis 50 Actual production completion status

50 Partially completed item (1) 9 Completed item (2) 9 Completed item (3) 12 Features and innovations 20

Microcontroller Paper 7 DC Stabilized Power Supply

1. Mission

Design and manufacture stable power supplies that convert AC to DC.

II. Requirements

1. Basic requirements

(1) When the input voltage of the regulated power supply is 220V, 50Hz, and the voltage variation range is +15% to -20%, the following conditions are met:

a. The output voltage can be adjusted from +9V to +12V

b. Maximum output current is 1.5A

c. Voltage regulation rate ≤ 0.2% (input voltage 220V, range of +15% to -20%, no load to full load)

d. Load regulation ≤ 1% (at minimum input voltage, full load)

e. Ripple voltage (peak-to-peak) ≤ 5mV (at minimum input voltage, full load)

f. Efficiency ≥ 40% (output voltage 9V, input voltage 220V, full load)

g. With over-current and short-circuit protection function

(2) When the input voltage of the regulated current power supply is fixed at +12V:

a. Output current: 4～20mA adjustable

b. Load regulation rate ≤ 1% (when input voltage is +12V and load resistance changes from 200Ω to 300Ω, the relative change rate of output current is 20mA)

(3) When the input voltage of the DC-DC converter is +9V to +12V:

a. Output voltage is +100V, output current is 10mA

b. Voltage regulation rate ≤ 1% (input voltage range +9V～+12V)

c. Load regulation rate ≤ 1% (at input voltage +12V, no load to full load)

d. Ripple voltage (peak-to-peak) ≤ 100mV (at input voltage +9V, full load)

2. Development part

(1) Expanded functions

a. After eliminating the short circuit fault, it will automatically return to normal state

b. Overheat protection

c. Prevent "overshoot" when turning on and off

(2) Improve the technical indicators of the voltage-stabilized power supply

a. Improve voltage regulation and load regulation

b. Expand the output voltage adjustment range and increase the maximum output current value

(3) Improvement of DC-DC converter

a. Improve efficiency (at 100V, 100mA)

b. Increase the output voltage

(4) Digital display of output voltage and output current

3. Rating opinions

Project Scoring 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 50 Partial completion of item (1) 9 Completion of item (2) 15 Completion of item (3) 6 Completion of item (4) 10 Features and innovation 10

Single chip computer paper eight simple digital frequency meter

1. Mission

Design and make a simple frequency meter with digital display.

II. Requirements

1. Basic requirements

(1) Frequency measurement

a. Measurement range signal: square wave, sine wave; amplitude: 0.5V~5V; frequency: 1Hz~1MHz

b. Measurement error ≤ 0.1%

(2) Cycle measurement

a. Measurement range signal: square wave, sine wave; amplitude: 0.5V~5V; frequency: 1Hz~1MHz

b. Measurement error ≤ 0.1%

(3) Pulse width measurement

a. Measurement range signal: pulse wave; amplitude: 0.5V～5V; pulse width ≥100μs

b. Measurement error ≤ 1%

(4) Display

Decimal digital display, display refresh time 1 to 10 seconds continuously adjustable, the above three measurement functions are indicated by light-emitting diodes of different colors.

(5) It has self-calibration function, and the time scale signal frequency is 1MHz.

(6) Design and manufacture a voltage-stabilized power supply that meets the requirements of this design task.

2. Development part

(1) The frequency measurement range is extended to 0.1Hz~10MHz (signal amplitude 0.5V~5V), and the measurement error is reduced to 0.01% (maximum gate time ≤10s).

(2) Measure and display the duty cycle of a periodic pulse signal (amplitude 0.5V~5V, frequency 1Hz~1kHz). The duty cycle range is 10%~90%, and the measurement error is ≤1%.

(3) Perform frequency measurements of small signals within the range of 1 Hz to 1 MHz and with a measurement error of ≤ 1%, and propose and implement anti-interference measures.

3. Rating opinions

Basic requirements for project scoring

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

Complete item (1) 10 Complete item (2) 10 Complete item (3) 20 Features and innovations 10

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