parking-distance-meter

Overview

The Parking Distance Meter is an ESP8266-based device that helps with parking by displaying the distance to nearby objects. It uses an ultrasonic sensor to measure distance and displays it on a 7-segment LED display. The device automatically turns off the display when the car is out of range or when the distance has remained static for a set period.

Hardware Requirements

• ESP8266 board (D1 Mini recommended)
• Ultrasonic distance sensor (HC-SR04 or similar)
• TM1637 7-segment LED display
• Relay module
• Power supply

Pin Configuration

The default pin configuration in the YAML file is:

• Echo Pin: GPIO5 (D1 on D1 Mini)
• Trigger Pin: GPIO4 (D2 on D1 Mini)
• Relay Pin: GPIO14 (D5 on D1 Mini)
• CLK Pin: GPIO12 (D6 on D1 Mini)
• DIO Pin: GPIO13 (D7 on D1 Mini)

Configuration File

The parking-distance-meter-{id}.yaml file is an ESPHome configuration file that defines how the device works. To use it:

1. Replace {id} in the filename with your unique device ID (e.g., parking-distance-meter-k062hx.yaml)
2. Customize the configuration parameters as needed

Key Configuration Parameters

Device Identification

• id: Unique identifier for the device (e.g., "k062hx")
• name: Base name for the device (default: "parking-sensor")
• friendly_name: Human-readable name (default: "Parking Distance Meter v3")

Sensor Configuration

• update_interval: How often the sensor takes measurements (default: 0.15s)
• max_distance: Maximum valid distance in meters (default: 1.5m)
• pulse_duration: Duration of ultrasonic pulse (default: 20μs)

Display Configuration

• display_update_interval: How often the display updates (default: 0.15s)

Relay Configuration

• debounce_time: Time in milliseconds to debounce sensor readings (default: 1000ms)
• static_timeout: Time in milliseconds after which the display turns off if the distance remains static (default: 300000ms = 5 minutes)
• static_diff: Minimum difference in cm to consider the distance as changed (default: 2.0cm)

Network Configuration

• wifi_fallback_password: Password for the fallback AP mode
• ota_password: Password for OTA updates
• encryption_key: Key for encrypted communication with Home Assistant

How It Works

Distance Measurement

The device uses an ultrasonic sensor to measure the distance to objects. The measurements are:

• Taken at regular intervals (defined by update_interval)
• Filtered using a median filter to reduce noise
• Converted from meters to centimeters for display

Display Logic

The 7-segment display shows the current distance in centimeters. The display behavior is controlled by several mechanisms:

1. Maximum Distance Threshold:

   • When the measured distance exceeds max_distance, the display turns off after debounce_time milliseconds
   • When the distance returns below max_distance, the display turns back on

2. Static Distance Detection:

   • The device tracks if the distance remains stable (changes less than static_diff cm)
   • If the distance remains static for longer than static_timeout (5 minutes by default), the display turns off
   • Any significant movement resets this timer and turns the display back on

Network Connectivity

The device connects to your home network and integrates with Home Assistant:

• Supports OTA updates
• Provides a web server interface
• Creates a fallback access point if WiFi connection fails
• Integrates with Home Assistant via the ESPHome API

Home Assistant Integration

The device exposes:

• A sensor entity for the measured distance
• A switch entity to control the relay/display manually

Customization

To customize the device for your needs, modify the substitution variables at the top of the YAML file before flashing it to your ESP8266 device.