Tutorial 14: Raspberry Pi 4 / Zero 2W - Setup Guide

Raspberry Pi 4 vs Zero 2W Overview

OceanRemote will support two Raspberry Pi models for IoT control:

What Makes Raspberry Pi Different

Unlike ESP8266, ESP32, and Pico W (microcontrollers), the Raspberry Pi 4 and Zero 2W are full Linux computers. This means:

• Full Operating System - Runs Raspberry Pi OS (Linux)
• Python Native - OceanRemote firmware runs as a Python script, not compiled C++
• Multi-tasking - Can run multiple programs simultaneously
• Storage - Uses SD card for storage (GBs, not MBs)
• Networking - Full TCP/IP stack, SSH access, web server capabilities
• USB Ports - Can connect USB devices (cameras, storage, etc.)

Prerequisites

• Raspberry Pi 4 (2GB+ recommended) or Raspberry Pi Zero 2 W
• MicroSD card (16GB minimum, 32GB recommended)
• 5V 3A USB-C power supply (Pi 4) or 5V 2.5A (Zero 2W)
• Micro HDMI cable (Pi 4) or mini HDMI (Zero 2W) - optional for headless setup
• USB keyboard and mouse (for initial setup)
• Ethernet cable (optional, for faster setup)
• Relay module (5V, active LOW recommended)
• Dupont jumper wires (female-female)
• Optional: DHT22, DS18B20, or NTC sensor

Step 1: Install Raspberry Pi OS

Download Raspberry Pi Imager

1. Go to https://www.raspberrypi.com/software/
2. Download Raspberry Pi Imager for your operating system
3. Install and run the Imager

Flash the SD Card

1. Insert your microSD card into your computer
2. In Raspberry Pi Imager, click Choose Device and select your model (Pi 4 or Zero 2 W)
3. Click Choose OS → Raspberry Pi OS (other) → Raspberry Pi OS Lite (32-bit) (headless) or Raspberry Pi OS (32-bit) (with desktop)
4. Click Choose Storage and select your SD card
5. Click the gear icon (⚙️) to configure advanced options:
   • Set hostname: oceanremote-pi or your choice
   • Enable SSH: Check "Enable SSH" and "Use password authentication"
   • Set username/password: Default pi/raspberry (change for security)
   • Configure WiFi: Enter your SSID and password
   • Set locale settings: Timezone, keyboard layout
6. Click Write and wait for the process to complete

Step 2: Boot and Connect to Your Pi

Option A: With Monitor (Desktop)

1. Insert the SD card into your Pi
2. Connect HDMI cable to monitor
3. Connect USB keyboard and mouse
4. Connect power supply
5. Wait for boot (30-60 seconds)
6. Log in with your username/password
7. Open Terminal (Ctrl+Alt+T)

Option B: Headless (SSH)

1. Insert the SD card into your Pi
2. Connect power supply
3. Wait 1-2 minutes for boot
4. Find your Pi's IP address:
   • Check your router's DHCP client list
   • Use ping raspberrypi.local (Mac/Linux)
   • Use arp -a (Windows)
5. Connect via SSH:
   ssh pi@[IP_ADDRESS]

Step 3: Update Raspberry Pi OS

Once connected, run these commands to update your system:

sudo apt update
sudo apt upgrade -y
sudo apt install python3-pip python3-venv git -y

Step 4: Install Python Libraries

OceanRemote firmware for Raspberry Pi requires these Python libraries:

# Install required packages
sudo pip3 install requests
sudo pip3 install RPi.GPIO
sudo pip3 install adafruit-circuitpython-dht
sudo apt install python3-libgpiod -y

# For DS18B20 sensor (optional)
sudo modprobe w1-gpio
sudo modprobe w1-therm

Step 5: Enable GPIO Access

To control GPIO pins without sudo, add your user to the gpio group:

sudo usermod -a -G gpio pi
sudo reboot

Step 6: Raspberry Pi GPIO Pinout

The 40-pin GPIO header is identical on Pi 4 and Zero 2W:

                    Raspberry Pi 40-Pin GPIO Header
            ┌─────────────────────────────────────────────┐
            │  3.3V  │ 1 │ 2 │ 5V                       │
            │  GPIO2 │ 3 │ 4 │ 5V                       │
            │  GPIO3 │ 5 │ 6 │ GND                      │
            │  GPIO4 │ 7 │ 8 │ GPIO14 (TXD)             │
            │  GND   │ 9 │10 │ GPIO15 (RXD)             │
            │  GPIO17│11 │12 │ GPIO18                   │
            │  GPIO27│13 │14 │ GND                      │
            │  GPIO22│15 │16 │ GPIO23                   │
            │  3.3V  │17 │18 │ GPIO24                   │
            │  GPIO10│19 │20 │ GND                      │
            │  GPIO9 │21 │22 │ GPIO25                   │
            │  GPIO11│23 │24 │ GPIO8                    │
            │  GND   │25 │26 │ GPIO7                    │
            │  GPIO0 │27 │28 │ GPIO1                    │
            │  GPIO5 │29 │30 │ GND                      │
            │  GPIO6 │31 │32 │ GPIO12                   │
            │  GPIO13│33 │34 │ GND                      │
            │  GPIO19│35 │36 │ GPIO16                   │
            │  GPIO26│37 │38 │ GPIO20                   │
            │  GND   │39 │40 │ GPIO21                   │
            └─────────────────────────────────────────────┘

OceanRemote Default GPIO Assignments (Coming Soon)

Step 7: Wiring Relays to Raspberry Pi

Relay Wiring Diagram (Raspberry Pi):
┌─────────────┐                    ┌─────────────────────────────┐
│  Raspberry  │                    │      5-Channel Relay Module  │
│   Pi 4/Zero │                    ├─────────────────────────────┤
├─────────────┤                    │  IN1 │ GPIO17 (Pin 11)       │
│   5V Pin 2  ├────────────────────┤  IN2 │ GPIO27 (Pin 13)       │
│   GND       ├────────────────────┤  IN3 │ GPIO22 (Pin 15)       │
│   GPIO17    ├────────────────────┤  IN4 │ GPIO23 (Pin 16)       │
│   GPIO27    ├────────────────────┤  IN5 │ GPIO24 (Pin 18)       │
│   GPIO22    ├────────────────────┤  VCC │ 5V (Pin 2 or 4)       │
│   GPIO23    ├────────────────────┤  GND │ GND                   │
│   GPIO24    ├────────────────────┘                             │
└─────────────┘                                                  │
                          ┌─────────────────────────────────────┘

Step 8: Wiring Sensors

DHT22 Temperature & Humidity Sensor

DS18B20 Digital Temperature Sensor

Step 9: Power Requirements

Raspberry Pi 4

• Official Power Supply: 5V 3A USB-C
• Typical current draw: 600-800mA (idle), 1.2-2A (full load)
• With relays: Use external 5V supply for relay module (do NOT power from Pi's 5V pin if using many relays)

Raspberry Pi Zero 2 W

• Power Supply: 5V 2.5A USB micro
• Typical current draw: 120-150mA (idle), 300-400mA (full load)
• With relays: Use external 5V supply for relay module

Step 10: Running OceanRemote Firmware (Coming Soon)

Once the firmware is released, you'll:

1. Generate Python firmware from the OceanRemote dashboard
2. Copy the code to your Pi
3. Run the script: python3 oceanremote_firmware.py
4. Set up auto-start on boot (systemd service)

# Example future commands (when firmware is available)
wget https://www.oceanremote.net/firmware/pi_firmware.py
python3 pi_firmware.py

Troubleshooting

Pi Won't Boot

• Check power supply (5V 3A for Pi 4, 5V 2.5A for Zero 2W)
• Re-flash SD card with Raspberry Pi Imager
• Check activity LED (green LED should blink)
• Try a different SD card (some are incompatible)

Can't SSH to Pi

• Enable SSH in Imager's advanced options
• Create empty ssh file on boot partition
• Check your router's DHCP client list for IP address
• Try ping raspberrypi.local

GPIO Permission Denied

• Run sudo usermod -a -G gpio pi and reboot
• Or run Python with sudo (not recommended)

Relays Not Responding

• Verify relay VCC is connected to 5V (external supply recommended)
• Test GPIO with a simple LED before connecting relay
• Check that you're using BCM numbering (not physical pin numbers)

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.OUT)

while True:
    GPIO.output(17, GPIO.HIGH)
    time.sleep(1)
    GPIO.output(17, GPIO.LOW)
    time.sleep(1)

Next Steps

While waiting for OceanRemote firmware for Raspberry Pi:

• Tutorial 15: Flashing Firmware to Your Device (for ESP boards)
• Tutorial 16-20: Working with sensors (applicable to Pi too)
• Sign up for updates: We'll notify you when Raspberry Pi firmware is ready!