T-Relay Quick Start

Required Libraries

Library	Version	Source
(No external libraries required)	—	—

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Arduino

PlatformIO (Recommended)

1. Install VS Code and the PlatformIO IDE extension
2. Clone the repository:

   git clone https://github.com/Xinyuan-LilyGO/T-Relay.git

3. Open platformio.ini and select the target example
4. Click ✓ to build, connect via USB, click → to upload

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Arduino IDE

1. Install ESP32 Board Support

1. Open Arduino IDE → File → Preferences
2. Add to "Additional Board Manager URLs":

   https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

3. Go to Tools → Board → Boards Manager, search esp32, install esp32 by Espressif Systems

2. Board Settings

Setting	Value
Board	ESP32 Dev Module
Upload Speed	921600
CPU Frequency	240 MHz (WiFi)
Flash Size	4 MB (32Mb)
Partition Scheme	Default 4MB with spiffs

3. Upload

Connect via USB and click Upload.

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Peripheral Examples

Basic Relay Control

// T-Relay GPIO pin definitions (adjust to your version)
#define RELAY1  21
#define RELAY2  19
#define RELAY3  18
#define RELAY4   5

void setup() {
    pinMode(RELAY1, OUTPUT);
    pinMode(RELAY2, OUTPUT);
    pinMode(RELAY3, OUTPUT);
    pinMode(RELAY4, OUTPUT);
    // Relays are active-HIGH
    digitalWrite(RELAY1, LOW);
    digitalWrite(RELAY2, LOW);
    digitalWrite(RELAY3, LOW);
    digitalWrite(RELAY4, LOW);
}

void loop() {
    digitalWrite(RELAY1, HIGH);  // Turn relay 1 ON
    delay(1000);
    digitalWrite(RELAY1, LOW);   // Turn relay 1 OFF
    delay(1000);
}

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FAQ

Q: Upload keeps failing?
A: Hold BOOT, press and release RST, then release BOOT to enter download mode.

Q: Relays not switching?
A: Verify the relay control GPIO pins for your board version. T-Relay uses active-HIGH control by default.

Q: What load can T-Relay switch?
A: Each relay channel can switch up to 10 A at 250 VAC or 30 VDC. Do not exceed these ratings.