Example 51: OLED Temperature and Humidity Display

Scenario Overview

Use a DHT11/DHT22 temperature and humidity sensor to collect environmental data, and display real-time temperature and humidity values on an SSD1306 OLED screen. This is a typical "sensor read → screen display" linkage scenario.

Required Hardware

Module	Model	Purpose
Temp & Humidity Sensor	DHT11 / DHT22	Collect temperature and humidity
OLED Display	SSD1306 0.96" I2C	Display data
ESP32 Dev Board	Puzhong ESP32	Main controller

Hardware Wiring

DHT11 Wiring

DHT11 Pin	ESP32 GPIO	Description
VCC	3.3V	Power
DATA	GPIO 32	Data pin
GND	GND	Ground

SSD1306 OLED Wiring

OLED Pin	ESP32 GPIO	Description
VCC	3.3V	Power
GND	GND	Ground
SDA	GPIO 21	I2C Data
SCL	GPIO 22	I2C Clock

Peripheral Execution Linkage Configuration

Scenario 1: Timed Read and Display Temp/Humidity (Timer Trigger)

Function: Read DHT11 data every 3 seconds and display on OLED

Web Interface Configuration Steps

Step 1: Create Rule

1. Click Peripheral Configuration in the left menu → Switch to Peripheral Execution Management tab
2. Click Add Rule button
3. Fill in basic configuration:
   • Rule Name: OLED Display Temp & Humidity
   • Report Data: ✅ Enabled
   • Enable: ✅ Enabled

Step 2: Configure Trigger (Timer Trigger)

1. Click Add Trigger button

2. Fill in trigger configuration:

   Field	Value	Description
   Trigger Type	Select Timer Trigger	Timed collection
   Timer Mode	Select Fixed Interval	Millisecond interval
   Interval	3000	3 seconds

Step 3: Configure Actions (2 actions required)

Action 1: Read Sensor Data

1. Click Add Action button
2. Fill in:
   • Action Type: Select Sensor Read
   • Target Peripheral: Select dht1

Action 2: OLED Display Data

1. Click Add Action button again

2. Fill in:

   • Action Type: Select OLED Display
   • Target Peripheral: Select oled1
   • Display Template:

   === FastBee ===
   Temp: {dht1.temperature}C
   Humi: {dht1.humidity}%
   ===============

3. Click Save button

---

Scenario 2: Display with Temperature Alarm (Poll Trigger)

Function: Display warning and trigger buzzer when temperature exceeds 35°C

Configuration Steps:

1. Create a rule, name: Temperature Alarm Display
2. Trigger configuration:
   • Trigger Type: Select Poll Trigger
   • Target Peripheral: Select dht1
   • Data Field: temperature
   • Operator: >
   • Threshold: 35
   • Poll Interval: 5000
3. Action configuration (2 actions required):
   • Action 1: Select OLED Display, target oled1, template:

     !! WARNING !!
     High Temp!
     {dht1.temperature}C
     Check cooling

   • Action 2: Select HIGH, target buzzer1 (buzzer must be configured in advance)
4. Click Save

Complete Configuration Import

Save the following as a JSON file and import to peripherals.json via the Web interface file management:

[
  {
    "id": "dht1",
    "name": "DHT11 Temp & Humidity",
    "type": 38,
    "enabled": false,
    "pins": [32],
    "params": {
      "driver": "DHT",
      "model": "DHT11",
      "interval": 3000
    }
  },
  {
    "id": "oled1",
    "name": "OLED Display",
    "type": 36,
    "enabled": false,
    "pins": [21, 22],
    "params": {
      "driver": "SSD1306",
      "width": 128,
      "height": 64,
      "i2cAddress": "0x3C"
    }
  }
]

Display Output

OLED display example:

=== FastBee ===
Temp: 25.3C
Humi: 60.5%
===============

• 128x64 resolution supports 4 lines of text (16px font size)
• Supports Chinese and English characters (Chinese characters occupy two character widths)
• {periphId.field} in the template will be replaced with actual sensor values

Extension Suggestions

1. Multi-Sensor Display: Add BMP280 barometric pressure data, alternate between multiple pages
2. Graphical Display: Use script action to draw temperature trend curves
3. Time Display: Combine NTP time to show clock on screen
4. WiFi Status: Display WiFi connection status and IP address

Notes

1. I2C Address: SSD1306 default address is usually 0x3C, some modules use 0x3D
2. Refresh Rate: OLED refresh should not be too frequent (≥ 1000ms), otherwise flickering may occur
3. Burn-in: Long-duration static content may cause OLED burn-in. Recommend periodically switching display content
4. DHT Sampling Rate: DHT11 maximum 1 time/second, DHT22 maximum 1 time/2 seconds
5. Shared I2C: OLED can share I2C bus with BMP280 and other sensors