Example 36: Touch Sensor

Experiment Overview

ESP32 has built-in capacitive touch sensors supporting 10 touch pins (Touch0~Touch9), enabling touch detection without external components. FastBee provides the GPIO_TOUCH peripheral type (type: 21) for direct support.

Hardware Wiring

Touch Channel	GPIO Pin	Description
Touch0	GPIO4	Touch input 0
Touch2	GPIO2	Touch input 2
Touch3	GPIO15	Touch input 3
Touch4	GPIO13	Touch input 4
Touch5	GPIO12	Touch input 5
Touch6	GPIO14	Touch input 6
Touch7	GPIO27	Touch input 7
Touch8	GPIO33	Touch input 8
Touch9	GPIO32	Touch input 9

Touch pins can detect touch by connecting directly to a metal pad or conductive material.

JSON Configuration Example

{
  "peripherals": [
    {
      "id": "touch_01",
      "name": "Touch Input",
      "type": 21,
      "enabled": false,
      "pins": [4],
      "params": {}
    }
  ]
}

Peripheral Execution Linkage

Scenario: Touch Toggle Light (Polling Trigger)

Feature: Toggle LED on/off when touch sensor is touched

Web UI Configuration Steps

Step 1: Ensure LED Peripheral is Configured

• Peripheral ID: led_d1
• Type: GPIO Output

Step 2: Create Rule

1. Click Peripheral Execution in the left menu
2. Click New Rule button
3. Fill in basic configuration:
   • Rule Name: Touch Toggle Light
   • Report Data: ✅ Enabled
   • Enable: ✅ Enabled

Step 3: Configure Trigger (Polling Trigger)

1. Click Add Trigger button

2. Fill in trigger configuration:

   Field	Value	Description
   Trigger Type	Select Polling Trigger	Periodic condition check
   Target Peripheral	Select touch_01	Touch sensor
   Polling Interval	100	100ms
   Condition Expression	value < 40	Touch threshold

Step 4: Configure Action

1. Click Add Action button

2. Fill in:

   • Action Type: Select Toggle Level
   • Target Peripheral: Select led_d1

3. Click Save button

ESP32 Touch Pin List

Touch Channel	GPIO Pin	Touch Channel	GPIO Pin
Touch0	GPIO4	Touch5	GPIO12
Touch2	GPIO2	Touch6	GPIO14
Touch3	GPIO15	Touch7	GPIO27
Touch4	GPIO13	Touch8	GPIO33
		Touch9	GPIO32

⚠️ Note: Touch1 (GPIO0) is not recommended; it may affect touch readings when WiFi is active

Notes

1. Threshold: Value decreases when touched (typically <40); higher when not touched (>60); determine threshold through actual testing
2. Wire Length: Wire from touch pin to sensing pad should not be too long (<30cm)
3. ESP32-S3: S3 has improved touch sensors with different threshold ranges
4. Anti-False-Touch: Add touch confirmation delay to avoid false triggers
5. WiFi Impact: WiFi operation may slightly affect touch readings