Tutorial 07: Setting Up Raspberry Pi Pico W in Arduino IDE

Introduction to the Raspberry Pi Pico W

The Raspberry Pi Pico W is the official microcontroller board from the Raspberry Pi Foundation, featuring their in-house RP2040 chip. Released in 2022, it brought WiFi capabilities to the popular Pico platform, making it an excellent choice for IoT projects.

Pico W vs Regular Pico

• Raspberry Pi Pico - Original version. No WiFi or Bluetooth. Requires Ethernet shield for internet.
• Raspberry Pi Pico W - Adds WiFi (2.4 GHz 802.11n). Same form factor, same pinout. The "W" stands for Wireless.

Step 1: Add Raspberry Pi Pico W to Arduino IDE

The Pico W uses a different core than ESP boards. Here's how to add it:

1. Open Arduino IDE
2. Go to File → Preferences (Windows/Linux) or Arduino IDE → Settings (Mac)
3. In the "Additional Boards Manager URLs" field, add the Pico URL:

If you already have ESP8266/ESP32 URLs, separate them with commas:

4. Click OK
5. Go to Tools → Board → Boards Manager
6. Search for "pico" or "rp2040"
7. Find "Raspberry Pi Pico/RP2040 by Earle F. Philhower" and click Install
8. Wait for installation to complete (2-3 minutes)

Step 2: Selecting Your Board

After installation, select your board:

1. Go to Tools → Board → Raspberry Pi RP2040 Boards
2. Select "Raspberry Pi Pico W"

Step 3: Configuring Board Settings

Once you've selected your board, configure these settings:

• Flash Size: 2MB (no FS) or 2MB (FS:1MB) - OceanRemote firmware uses about 400KB, so either works
• CPU Speed: 133 MHz (default, stable)
• Optimize: Small (-Os) (Standard) - Reduces code size
• RTTI: Disabled (saves memory)
• Stack Protection: Disabled
• C++ Exceptions: Disabled (saves memory)
• Debug Port: Disabled
• Debug Level: None
• USB Stack: Adafruit TinyUSB (recommended)
• IP/Bluetooth Stack: IPv4 Only
• Upload Method: Default (UF2)
• Port: Pico W doesn't use a COM port like ESP boards. Instead, you'll put it in BOOTSEL mode (see below).

Step 4: Installing Required Libraries for Pico W

OceanRemote firmware requires these libraries for Pico W:

1. Go to Sketch → Include Library → Manage Libraries
2. Search for and install each library:

• ArduinoJson by Benoit Blanchon (version 6.x) - Required for all devices
• DHT sensor library by Adafruit - Required only if using DHT22 sensor
• Adafruit Unified Sensor - Dependency for DHT library
• OneWire by Jim Studt - Required only if using DS18B20 sensor
• DallasTemperature by Miles Burton - Required only if using DS18B20 sensor

Step 5: Entering BOOTSEL Mode (How to Upload)

The Pico W doesn't have an auto-reset circuit like ESP boards. You need to manually enter BOOTSEL mode:

1. Disconnect the USB cable from your Pico W
2. Press and HOLD the BOOTSEL button (white button on the board)
3. While holding BOOTSEL, connect the USB cable to your computer
4. Release the BOOTSEL button after 2 seconds
5. A drive called "RPI-RP2" should appear on your computer
6. In Arduino IDE, click Upload
7. Arduino will compile and copy the UF2 file to the Pico W
8. The Pico W will automatically reset and run your code

Step 6: Testing Your Pico W

Before flashing OceanRemote firmware, test your setup with a simple blink sketch:

// Pico W Blink Test
// The built-in LED is on pin 25 (LED_BUILTIN)

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(115200);
  Serial.println("Pico W is alive!");
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // LED ON
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);    // LED OFF
  delay(1000);
}

1. Copy the code above into Arduino IDE
2. Select your board (Tools → Board → Raspberry Pi RP2040 Boards → Raspberry Pi Pico W)
3. Put your Pico W in BOOTSEL mode (hold BOOTSEL, connect USB, release)
4. Click Verify (checkmark) to compile
5. Click Upload (right arrow)
6. Open Serial Monitor (Tools → Serial Monitor) at 115200 baud
7. You should see "Pico W is alive!" and the LED blinking

Pico W Pin Reference for OceanRemote

When generating firmware, OceanRemote uses these default pin mappings for Pico W:

Pico W Special Features

• Programmable I/O (PIO) - Can create custom interfaces (NeoPixels, SD cards, etc.)
• 12-bit ADC - Better analog reading than ESP8266 (10-bit) and comparable to ESP32
• Dual-core - Can run WiFi on one core, application on the other
• USB Mass Storage - Upload code by copying UF2 files (no drivers needed)
• Low Power - Can run on two AA batteries

Next Steps

Now that your Pico W is ready, continue with:

• Tutorial 08: Installing Required Libraries (detailed)
• Tutorial 09: Configuring Board Settings (detailed)
• Tutorial 13: Raspberry Pi Pico W Pinout and Wiring Guide
• Tutorial 15: Flashing Firmware to Your Device