Example 52: TM1637 Seven-Segment Temp/Humidity Display

Scenario Overview

Use a DHT11/DHT22 temperature and humidity sensor to collect data, and alternately display temperature and humidity values on a TM1637 four-digit seven-segment display. Suitable for scenarios requiring long-distance data observation (e.g., greenhouse, server room temperature monitoring).

Required Hardware

Module	Model	Purpose
Temp & Humidity Sensor	DHT11 / DHT22	Collect temperature and humidity
Seven-Segment Display	TM1637 Four-Digit	Display values
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

TM1637 Seven-Segment Wiring

TM1637 Pin	ESP32 GPIO	Description
VCC	3.3V / 5V	Power
GND	GND	Ground
CLK	GPIO 18	Clock pin
DIO	GPIO 19	Data pin

Peripheral Execution Linkage Configuration

Scenario 1: Alternate Display of Temperature and Humidity (Timer Trigger)

Function: Alternate display every 6 seconds (temperature 3s, humidity 3s)

Web Interface Configuration Steps

Rule 1: Display Temperature

1. Click Peripheral Execution in the left menu

2. Click Add Rule button

3. Fill in basic configuration:

   • Rule Name: Display Temperature
   • Report Data: ✅ Enabled
   • Enable: ✅ Enabled

4. Configure trigger:

   • Trigger Type: Select Timer Trigger
   • Timer Mode: Select Fixed Interval
   • Interval: 6000 (6 seconds)
   • Time Offset: 0 (0 second offset)

5. Configure actions (2 actions required):

   • Action 1: Select Sensor Read, target dht1
   • Action 2: Select Seven-Segment Display, target tm1637_1, template {dht1.temperature}

6. Click Save button

Rule 2: Display Humidity

1. Create another rule, name: Display Humidity
2. Trigger configuration:
   • Trigger Type: Select Timer Trigger
   • Interval: 6000 (6 seconds)
   • Time Offset: 3000 (3 second offset, staggered from temperature)
3. Action configuration:
   • Action 1: Select Sensor Read, target dht1
   • Action 2: Select Seven-Segment Display, target tm1637_1, template {dht1.humidity}
4. Click Save

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Scenario 2: Temperature Alarm Blink (Poll Trigger)

Function: Seven-segment display blinks and buzzer triggers when temperature exceeds 35°C

Configuration Steps:

1. Create a rule, name: High Temp Blink
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 Seven-Segment Display, target tm1637_1, template {dht1.temperature}, ✅ Enable blink
   • Action 2: Select HIGH, target buzzer1 (buzzer must be configured in advance)
4. Click Save

Complete Configuration Import

[
  {
    "id": "dht1",
    "name": "DHT11 Temp & Humidity",
    "type": 38,
    "enabled": false,
    "pins": [32],
    "params": {
      "driver": "DHT",
      "model": "DHT11",
      "interval": 3000
    }
  },
  {
    "id": "tm1637_1",
    "name": "Four-Digit Seven-Segment",
    "type": 47,
    "enabled": false,
    "pins": [18, 19],
    "params": {
      "brightness": 4,
      "colon": true
    }
  }
]

Display Output

TM1637 four-digit seven-segment display:

Temperature mode: 25.3 (shows 25.3, colon blinks to indicate active sampling)
Humidity mode: 60.5 (shows 60.5)

• Supports displaying values from 0-9999
• Supports one decimal point
• Colon can indicate status (blinking = normal, steady = alarm)

Comparison with OLED Solution

Feature	TM1637 Seven-Segment	SSD1306 OLED
Display Content	Numbers only	Text + graphics
Viewing Distance	Far (5-10m)	Near (< 1m)
Power Consumption	Higher	Very low
Suitable Scenarios	Factory/greenhouse/server room	Desktop/portable devices
Information Capacity	Low (4 digits)	High (multi-line text)

Notes

1. Display Precision: TM1637 has only 4 digits, temperature shows 25.3, humidity 60.5
2. Data Format: Sensor values are automatically truncated to displayable digits
3. Brightness Adjustment: Adjust brightness parameter per ambient light (0=dimmest, 7=brightest)
4. Refresh Rate: Recommend ≥ 1000ms refresh interval, too fast causes flickering
5. Pin Conflict: CLK/DIO can use any GPIO, avoid conflict with SPI devices