El escenario
A PIR motion sensor detects nearby movement, pulls its output high, and turns on an NPN transistor. The transistor energizes a relay coil, closing its contacts across the laptop's power button header to automatically start the laptop.
Qué hay en este dibujo
Lee las decisiones que hay detrás.
01
Use a relay to isolate the low-voltage control circuit from the laptop's power button contacts.
02
Add a flyback diode across the relay coil to suppress inductive voltage spikes and protect the transistor.
03
Include pull-down and decoupling components to ensure reliable triggering and noise immunity.
Ideal for kiosks, digital signage, automated test benches, or any laptop that should wake or power on when a person approaches the sensor.