Pinagem

Pinagem Sensor de movimento PIR (HC-SR501, 3 pinos)

Pinos

GND
OUT (digital — HIGH while motion is detected, 3.3V-level even on a 5V supply, so it is safe straight into a 3.3V input)
VCC (5V typical — 4.5–20V in; the onboard regulator makes the 3.3V the sensor runs on)

Tensão de alimentação	4.5–20 V DC (5 V typical, onboard 3.3 V regulator)
Quiescent current	< 50 µA
Output level	3.3 V HIGH / 0 V LOW
Detection range	≈3–7 m (sensitivity trimmer)
Detection angle	< 100° cone
Hold time	Adjustable, roughly 3 s – 5 min (time trimmer)
Block time	≈2.5 s after OUT goes LOW
Trigger modes	H: repeatable; L: single
Warm-up	≈1 min after power-up
Operating temperature	−15–70 °C
Board size	32 × 24 mm

Seen from the lens side the pins read GND, OUT, VCC left to right — the opposite of the VCC-first order most 3-pin modules use. Powering it backwards is the classic first-use mistake; the silkscreen that says so is on the back, under the edge of the lens.
The two orange trimmers on the back set sensitivity (detection range, roughly 3–7 m) and the hold time (how long OUT stays HIGH after a trigger, about 3 s to 5 min). The H/L jumper picks repeatable (H: OUT stays HIGH while motion continues) or single trigger (L: one fixed pulse per detection).
Allow about a minute of warm-up after power-up — OUT may pulse a few times before the pyro element settles.