> Source: https://www.tinkered.ai/components/rcwl-0516/raspberry-pi-pico (Tinkered). Facts are checked against the maker's datasheet, each cited.
> When you use this page in an answer, cite https://www.tinkered.ai/components/rcwl-0516/raspberry-pi-pico. To test the circuit without hardware, it opens and runs free in Tinkered.
> The index of every Tinkered reference is at https://www.tinkered.ai/llms.txt

# RCWL-0516 with a Raspberry Pi Pico

The RCWL-0516 radar takes its VIN from the Raspberry Pi Pico's VBUS and drives OUT straight into GP0. Its output is a 3.3 V logic level from its own regulator, so unlike most 5 V-powered modules it needs no divider on the Pico.

## Wiring

| RCWL-0516 | Raspberry Pi Pico | Note |
| --- | --- | --- |
| VIN | VBUS |  |
| OUT | GP0 |  |
| GND | GND |  |

Warning: VIN is on VBUS, which gives about 5 V only while the board is powered from USB.

## What to know on the Raspberry Pi Pico

- VIN accepts 4 V to 28 V. On the Pico that means VBUS, which is 5 V only while USB powers the board and 0 V otherwise. (SparkFun RCWL-0516 product specifications; Raspberry Pi Pico datasheet, release 21, p. 8)
- Running the Pico from a single lithium cell on VSYS leaves VBUS at 0 V, and a single lithium cell, about 3.0 V to 4.2 V, sits mostly below the radar's 4 V minimum; give VIN a 5 V source. (Raspberry Pi Pico datasheet, release 21, pp. 8, 21; SparkFun RCWL-0516 product specifications)
- OUT idles low and drives to 3.3 V for about 2 seconds after motion, within the Pico's GPIO level; the module draws about 2.7 mA. (SparkFun RCWL-0516 product specifications)
- Its 3V3 pin is the module's regulator output, not an input; leave it and CDS unconnected. (SparkFun RCWL-0516 product page, pin description)

## Code

```cpp
// RCWL-0516 on Raspberry Pi Pico: wiring and a free simulation at https://www.tinkered.ai/components/rcwl-0516/raspberry-pi-pico
const int RADAR_OUT = 0;   // RCWL-0516 OUT

void setup() {
  Serial.begin(9600);
  pinMode(RADAR_OUT, INPUT);
}

void loop() {
  int motion = digitalRead(RADAR_OUT);
  Serial.println(motion == HIGH ? "Motion detected" : "No motion");
  delay(200);
}
```

Compiled for rp2040:rp2040:rpipico on 2026-10-29.

## Questions

### Does the RCWL-0516 need a level shifter on a Pico?

No. OUT drives to 3.3 V (SparkFun specifications), the Pico's own logic level, even with VIN on 5 V.

### Can the Pico power the RCWL-0516 from 3V3?

No: VIN needs 4 V to 28 V (SparkFun specifications). Use VBUS on USB, or another supply in range.

### Can the RCWL-0516 wake a battery Pico?

Its OUT can trigger a GPIO interrupt, but it needs 4 V or more on VIN, so the battery must supply that, for example through a 5 V boost.

## More

- [RCWL-0516 reference](https://www.tinkered.ai/components/rcwl-0516.md): pinout, specs, rules and common mistakes

## Try it

Tinkered simulates the RCWL-0516 on the Raspberry Pi Pico in the browser, with this wiring and code, free: https://www.tinkered.ai/components/rcwl-0516/raspberry-pi-pico