HC-SR501 PIR with Nordic nRF52840 DK

Wiring for the HC-SR501 PIR motion sensor on the Nordic nRF52840 DK (nRF52840-QIAA, 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

Check before you power it on

• Supply: 5 V from the 5V pin.
• The HC-SR501 PIR works at 5 V, so its output (OUT → P1.03) can reach 5 V. The Nordic nRF52840 DK pins take only 3.3 V: add a voltage divider (for example 1 kΩ and 2 kΩ) or a level shifter on that wire.

Test code (Arduino)

The Arduino core for this board numbers its pins differently from the chip names, so no code is shown here. Use the pin names from your core’s variant file.

Arduino board: adafruit:nrf52:pca10056. Plug USB into the port on the short edge (interface MCU, J2) and set the power switch to ON; before the first Arduino sketch, burn the Adafruit bootloader and SoftDevice once.

Questions

Which Nordic nRF52840 DK pins do I use for the HC-SR501 PIR?

VCC → 5V, OUT → P1.03, GND → GND.

Does the HC-SR501 PIR work with the Nordic nRF52840 DK at 3.3 V?

The HC-SR501 PIR works at 5 V, so its output (OUT → P1.03) can reach 5 V. The Nordic nRF52840 DK pins take only 3.3 V: add a voltage divider (for example 1 kΩ and 2 kΩ) or a level shifter on that wire.

Full Nordic nRF52840 DK pinout · HC-SR501 PIR motion sensor: all pins and data

The HC-SR501 PIR on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Nano Arduino Uno R3 WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 ESP32-S3-DevKitC-1 NUCLEO-F401RE Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico Teensy 4.1

Other parts on the Nordic nRF52840 DK

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