HC-SR501 PIR with Raspberry Pi Pico 2

Wiring for the HC-SR501 PIR motion sensor on the Raspberry Pi Pico 2 (RP2350, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

HC-SR501 PIR pin	Role	Raspberry Pi Pico 2 pin	Notes
VCC	Power	VBUS	Needs 4.5 V or more: use VBUS
OUT	Output from the part	GP15
GND	Ground	GND

Check before you power it on

Supply: 5 V from the VBUS pin.
The HC-SR501 PIR works at 5 V. On the Raspberry Pi Pico 2, GP15 tolerate 5 V inputs, so a direct connection is fine while the board is powered.

Test code (Arduino)

void setup() {
  Serial.begin(115200);
  pinMode(15, INPUT);  // OUT on GP15
}

void loop() {
  Serial.println(digitalRead(15));
  delay(100);
}

Arduino board: rp2040:rp2040:rpipico2. If the board is not found, hold the BOOTSEL button while plugging in the USB cable.

Questions

Which Raspberry Pi Pico 2 pins do I use for the HC-SR501 PIR?

VCC → VBUS, OUT → GP15, GND → GND.

Does the HC-SR501 PIR work with the Raspberry Pi Pico 2 at 3.3 V?

Yes: the HC-SR501 PIR runs at 5 V and the Raspberry Pi Pico 2 uses 3.3 V signals, so no level shifting is needed.

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full Raspberry Pi Pico 2 pinout · HC-SR501 PIR motion sensor: all pins and data

The HC-SR501 PIR on other boards

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Other parts on the Raspberry Pi Pico 2

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