상황
A white cane for visually impaired users detects obstacle contact with a normally-open pushbutton, activating a vibration motor for tactile feedback.
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01
Use a low-side NPN transistor (2N2222) to switch the vibration motor without overloading the pushbutton contacts.
02
Include a flyback diode across the motor to suppress inductive voltage spikes.
03
Add a pull-down resistor on the transistor base so the motor stays off when no obstacle is touched.
Battery-powered tactile alert devices that activate a small DC motor or buzzer from a momentary contact sensor.