📖 What You'll Learn in This Tutorial:

✓ Understanding the ESP8266 D1 Large pinout
✓ Differences between D1 Mini and D1 Large
✓ Wiring relays to the D1 Large
✓ Connecting DHT22, DS18B20, and NTC sensors
✓ Power supply considerations

ESP8266 D1 Large Overview

The ESP8266 D1 Large is the bigger sibling of the D1 Mini. It uses the same ESP8266 chip but offers more GPIO pins broken out, making it ideal for complex projects that need many connections.

📏 D1 Large vs D1 Mini:

Feature	D1 Mini	D1 Large
Size	34mm x 25mm	55mm x 55mm
GPIO Pins	16	16 (same chip)
Power Pins	Limited	More 5V/3.3V/GND
Breadboard Friendly	Yes	Very (spaced pins)
Best For	Compact projects	Complex wiring, prototyping

Pinout Diagram

                    ESP8266 D1 Large Pinout
            ┌─────────────────────────────────────────────────────┐
            │  ┌───┐                                              │
            │  │USB│                                              │
            │  └───┘                                              │
            │                                                     │
            │  D0  ────┐  ┌────  D8      ┌────  A0               │
            │  D1  ────┤  ├────  D7      └────  3.3V              │
            │  D2  ────┤  ├────  D6      ┌────  GND               │
            │  D3  ────┤  ├────  D5      ├────  RST               │
            │  D4  ────┘  └────  D4      ├────  TX                │
            │                          ┌─┴────  RX                │
            │  D5  ────┐  ┌────  5V     │                         │
            │  D6  ────┤  ├────  GND    │                         │
            │  D7  ────┤  ├────  3.3V   │                         │
            │  D8  ────┘  └────  RST    │                         │
            │           3V3 GND RST TX RX                         │
            └─────────────────────────────────────────────────────┘

Pin to GPIO Mapping (Same as D1 Mini)

Board Pin	GPIO	OceanRemote Use	Notes
D0	GPIO16	Not used	Wake from deep sleep
D1	GPIO5	Relay 1	✅ Safe
D2	GPIO4	Relay 2 + Sensor	✅ Safe
D3	GPIO0	Relay 3	⚠️ Must be HIGH at boot
D4	GPIO2	Relay 4 / LED	⚠️ Must be HIGH at boot
D5	GPIO14	Relay 5	✅ Safe
D6	GPIO12	Not used	✅ Safe for expansion
D7	GPIO13	Not used	✅ Safe for expansion
D8	GPIO15	Not used	⚠️ Must be LOW at boot
A0	ADC	NTC Thermistor	Analog input 0-3.3V

⚠️ Boot Pin Notes (Same as D1 Mini):

GPIO0 (D3) - Must be HIGH at boot. Don't connect to GND.
GPIO2 (D4) - Must be HIGH at boot. Built-in LED is active LOW.
GPIO15 (D8) - Must be LOW at boot. Use with pull-down resistor.

Wiring Relays to D1 Large

OceanRemote uses 5 relays by default. The D1 Large has the same GPIO assignments as the D1 Mini:

Relay	D1 Large Pin	GPIO
Relay 1	D1	GPIO5
Relay 2	D2	GPIO4
Relay 3	D3	GPIO0
Relay 4	D4	GPIO2
Relay 5	D5	GPIO14

💡 D1 Large Advantage:

The D1 Large has more 5V and GND pins, making it easier to power multiple relay modules without using a breadboard.

Wiring Sensors

DHT22 Temperature & Humidity Sensor

DHT22 Pin	Connect to D1 Large
VCC	3.3V or 5V
DATA	D2 (GPIO4)
GND	GND

DS18B20 Digital Temperature Sensor

DS18B20 Pin	Connect to D1 Large
VDD	3.3V
DATA	D2 (GPIO4) + 4.7kΩ pull-up to 3.3V
GND	GND

NTC 10kΩ Thermistor (Analog)

NTC Thermistor Voltage Divider:
         3.3V
          │
          ▼
        ┌───┐
        │NTC│  ← 10kΩ NTC (resistance changes with temperature)
        └───┘
          │
          ├──────► A0 (ADC)  ← Voltage measured here
          │
        ┌───┐
        │10k│  ← Fixed 10kΩ resistor (R_series)
        │Ω  │
        └───┘
          │
         GND

⚠️ DS18B20 Pull-up Resistor Required!

A 4.7kΩ resistor must be connected between DATA (D2) and 3.3V. Without it, readings will fail.

Complete Wiring Diagram (5 Relays + DHT22)

                    COMPLETE D1 LARGE WIRING
            ┌─────────────────────────────────────────────────────┐
            │                                                     │
            │  ┌──────────┐     ┌─────────────────────────────┐  │
            │  │ D1 Large │     │      5-Channel Relay Module  │  │
            │  ├──────────┤     ├─────────────────────────────┤  │
            │  │   USB    │     │  IN1 │ D1 │ GPIO5           │  │
            │  │   5V     ├─────┤  IN2 │ D2 │ GPIO4           │  │
            │  │   GND    ├─────┤  IN3 │ D3 │ GPIO0           │  │
            │  │   3.3V   ├───┐ │  IN4 │ D4 │ GPIO2           │  │
            │  │   D1     ├───┤ │  IN5 │ D5 │ GPIO14          │  │
            │  │   D2     ├───┤ │  VCC │ 5V │                 │  │
            │  │   D3     ├───┤ │  GND │ GND│                 │  │
            │  │   D4     ├───┘ └─────────────────────────────┘  │
            │  │   D5     ├─────┐                                │
            │  │   A0     │     │    ┌─────────────────────┐     │
            │  └──────────┘     │    │      DHT22 Sensor    │     │
            │                   │    ├─────────────────────┤     │
            │                   └────┤ DATA │ D2            │     │
            │                        │ VCC  │ 3.3V          │     │
            │                        │ GND  │ GND           │     │
            │                        └─────────────────────┘     │
            └─────────────────────────────────────────────────────┘

D1 Large Advantages for Complex Projects

More Power Pins: Multiple 5V, 3.3V, and GND pins - no need for breadboard power rails.
Spaced Layout: Pins are spaced for easy jumper wire access.
Sturdy Mounting: Has mounting holes for secure installation.
Reset Button: Easy access to reset the board.
Better Labeling: All pins are clearly marked on the board.

💡 When to Choose D1 Large:

Choose the D1 Large for projects with many sensors (3+), multiple relay modules, or when you're prototyping and need easy access to pins. Choose D1 Mini for compact, permanent installations.

Power Supply Requirements

USB Power (Recommended for Testing)

Use a quality USB cable (not charge-only)
5V, 1A minimum (2A recommended with multiple relays)
Phone charger works well

External Power (For Permanent Installation)

Connect 5-12V DC to the 5V pin (regulated power)
Or use the VIN pin for unregulated 5-12V (board has voltage regulator)
The D1 Large has a more robust voltage regulator than the D1 Mini
Total current: ~200mA (D1 Large) + 70mA per active relay

⚠️ Power Warning:

Do NOT power relays from the D1 Large's 3.3V pin! Relays need 5V. Use the 5V pin or an external power supply.

Troubleshooting

Device Won't Boot

Check D3 (GPIO0) and D4 (GPIO2) - ensure they aren't pulled LOW at boot
Disconnect sensors and relays, test with bare board first
Try a different USB cable

Relays Not Clicking

Check relay VCC is connected to 5V (not 3.3V)
Verify relay logic (Positive vs Negative) in dashboard settings
Check that IN pins are properly connected to D1-D5

Sensor Not Reading

DS18B20: Verify 4.7kΩ pull-up resistor is installed
DHT22: Check wiring, try swapping DATA pin
NTC: Verify voltage divider circuit is correct

🔧 D1 Large vs D1 Mini Compatibility:

The D1 Large uses the exact same ESP8266 chip and GPIO assignments as the D1 Mini. Firmware generated for D1 Mini works identically on D1 Large. The only differences are physical layout and power pin availability.

Next Steps

Now that you understand the D1 Large wiring, continue with:

Tutorial 12: ESP32 Pinout and Wiring Guide
Tutorial 13: Raspberry Pi Pico W Pinout and Wiring
Return to Tutorial 02: Generate and flash your firmware!

🎯 You're Ready!

Your D1 Large is now properly wired. You can now generate firmware from the OceanRemote dashboard and flash your device!

Tutorial 11: ESP8266 D1 Large - Pinout and Wiring