The scenario
A highway monitoring station needs to detect vehicle speed between two infrared sensor pairs and display it on an LCD.
What is in this drawing
Read the decisions behind it.
01
Use IR sensor pairs 1 and 2 to capture entry and exit time
02
Use AT89S52 to compute speed from the sensor time difference
03
Use I2C LCD for clean readout and 7805 regulator for stable 5V
Reuse when designing a microcontroller-based highway speed checker or similar time-of-flight sensor projects.
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