GPIO Digital Output

Overview

GPIO digital output is used to control relays, LEDs, buzzers, DC motors, and other actuators. Outputs high/low levels to drive external loads.

Supported Peripheral Types

Type	type Value	Description
GPIO_DIGITAL_OUTPUT	12	Standard digital output

Pin Description

• ESP32: GPIO 0-5, 12-33 (some pins have limitations)
• ESP32-C3: GPIO 0-10, 18-21
• ESP32-S3: GPIO 0-21, 35-48

Note: GPIO 6-11 (ESP32) are reserved for internal Flash use and cannot be configured as outputs.

Typical Applications

Application	Wiring	Description
LED	GPIO → Resistor(220Ω) → LED → GND	High level to light up
Relay	GPIO → Relay Module IN	Most modules trigger on low level
Buzzer	GPIO → Active Buzzer+	High level to sound
DC Motor	GPIO → Motor Driver Module	Requires external driver circuit

Digital output directly drives physical loads. When configuring, keep the peripheral disabled first, confirm the trigger level of the relay or motor driver module, then verify with individual actions.

Configuration

Method 1: Web Interface Configuration (Recommended)

Different peripheral types will display different parameters. Before saving, verify peripheral ID, type, pins, and enable status.

Step 1: Navigate to Peripheral Management Page

1. Open a browser and navigate to the ESP32 IP address
2. After logging in, click Peripheral Configuration in the left menu

Step 2: Add GPIO Digital Output Peripheral

1. Click the Add Peripheral button

2. Fill in the configuration:

   Field	Value	Description
   Peripheral ID	led1 or relay1	Unique identifier
   Name	Status LED or Fan Relay	Display name
   Peripheral Type	GPIO Digital Output (type: 12)	Standard digital output
   Pin Configuration	2 or 15	Fill according to actual wiring
   Initial State	0	0=Low level, 1=High level

3. Click Save

Step 3: Verify Configuration

1. Find the newly added peripheral in the peripheral list
2. Click the Enable toggle
3. Use the control panel to test output state

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Method 2: JSON Configuration File Import

Add the following configuration to the peripherals array in data/config/peripherals.json:

LED Output

{
  "id": "led1",
  "name": "Status LED",
  "type": 12,
  "enabled": false,
  "pins": [2],
  "params": {
    "initialState": 0,
    "pwmChannel": 0,
    "pwmFrequency": 1000,
    "pwmResolution": 8,
    "defaultDuty": 0
  }
}

Relay Output (Low Level Trigger)

{
  "id": "relay1",
  "name": "Relay-Fan",
  "type": 12,
  "enabled": false,
  "pins": [15],
  "params": {
    "initialState": 0,
    "pwmChannel": 0,
    "pwmFrequency": 1000,
    "pwmResolution": 8,
    "defaultDuty": 0
  }
}

Buzzer

{
  "id": "buzzer",
  "name": "Alarm Buzzer",
  "type": 12,
  "enabled": false,
  "pins": [4],
  "params": {
    "initialState": 0,
    "pwmChannel": 0,
    "pwmFrequency": 1000,
    "pwmResolution": 8,
    "defaultDuty": 0
  }
}

Peripheral Execution Integration

GPIO digital output can serve as the action target of peripheral execution rules:

Action Type	actionType	Description
ACTION_HIGH	0	Output high level
ACTION_LOW	1	Output low level
ACTION_HIGH_INVERTED	13	Logic high (physical low level)
ACTION_LOW_INVERTED	14	Logic low (physical high level)
ACTION_BLINK	2	Blink (actionValue=interval ms)
ACTION_BREATHE	3	Breathing light effect

Web Interface Configuration Steps

Step 1: Create Execution Rule

1. Switch to the Peripheral Execution Management tab
2. Click the Add Rule button
3. Fill in basic configuration and configure triggers

Step 2: Add GPIO Action

1. Click the Add Action button

2. Fill in action configuration:

   Field	Value	Description
   Action Type	Select High Level or Low Level	Choose based on requirements
   Target Peripheral	Select relay1	GPIO output peripheral
   Execution Delay	0	Execute immediately

3. Click Save

💡 Tip: For low-level trigger relay modules, use "Logic High (Inverted)" or "Logic Low (Inverted)"

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JSON Configuration Example

{
  "targetPeriphId": "relay1",
  "actionType": 0,
  "actionValue": "",
  "useReceivedValue": false,
  "syncDelayMs": 0,
  "execMode": 0
}

Notes

1. Initial State: initialState of 0 means default low level on power-up, 1 means high level
2. Low-Level Trigger Relay: Use ACTION_HIGH_INVERTED(13) / ACTION_LOW_INVERTED(14) for logic inversion
3. Current Limit: ESP32 single pin maximum output current is 40mA; external driver circuit needed for high-power loads
4. PWM Parameters: Even for digital output type, PWM parameters in params must be retained (framework compatibility design), but they do not affect digital output behavior
5. Platform Downlink Control: Platform can control output state via MQTT: [{"id":"relay1","value":"1"}]