The ESP32-C3 Based Parking Assistant is an advanced parking sensor system that utilizes the ESP32-C3 super-mini micro-controller to provide accurate distance measurements and parking assistance.

This is the third iteration of my previously released parking assistant videos.

This parking assistant system uses ultrasonic sensors to help drivers park their vehicles accurately by providing visual and audible feedback about distance to the obstacles.

Components Required

• For this project I am using an ESP32-C3 Super Mini single core microcontroller which has a small formfactor and also includes Wi-Fi and Bluetooth (Arduino Uno or similar microcontroller).https://s.click.aliexpress.com/e/_omnke4z
• A HC-SR04 Ultrasonic Sensors (3-4 units) https://s.click.aliexpress.com/e/_ol2Np4t
• A 24 LED NeoPixel Ring https://s.click.aliexpress.com/e/_onkX369
• A TM1637 7-Segment display https://s.click.aliexpress.com/e/_o2Dm6fT
• A Buzzer https://s.click.aliexpress.com/e/_olXJAb3
• A 100 ohm Resistor https://s.click.aliexpress.com/e/_oCj0LAz
• A mini AC-DC 5V Adapter https://s.click.aliexpress.com/e/_ooQJdvj
• And mounting hardware printed using a 3D printer

Circuit Diagram

The wiring setup is pretty straightforward:

  Connect the microcontroller's Pin 4 to the buzzer

  Connect Pin 3 to the NeoPixel ring

  Wire Pin 2 to the Trig pin and Pin 1 to the Echo pin of the ultrasonic sensor

  Connect Pin 8 to CLK and Pin 9 to DIO of the TM1637 7-segment display

  Finally, connect all the positive (+) terminals to the power rail and all negative (-) terminals to ground

Breadboard Testing

Board and Library

-------------------

For the project to function, we first need to install the "ESP32-C3" board from the board manager. Additionally, we need to install the "TM1637Display.h" and "Adafruit_NeoPixel.h" libraries via the library manager.

I began by testing each component individually with the ESP32-C3 board to verify their functionality. Once all modules were confirmed to be working, I connected all of them to the ESP32 board and uploaded the program to orchestrate their combined operation. All source codes for this project are available on my GitHub repository.

We'll begin the "Parking Assistant" code by importing all the required libraries. Then, in the variable declaration section, we will define all pin numbers and the initial sensor values, making them globally accessible.

In the setup() section, the code first establishes a Wi-Fi connection to my Raspberry Pi-based home server. This feature is optional and can be disabled simply by removing or commenting out the relevant code section.

Following the network initialization, all pin modes (INPUT/OUTPUT) are defined, and the necessary hardware modules are initialized.

The loop() section operates continuously, performing two primary tasks:

  It reads the distance from the ultrasonic sensor and outputs the value to the 7-segment display.

  It also controls the NeoPixel LED color and number based on the measured distance, providing a visual indication of the approaching vehicle.

The system detects when the vehicle is stationary by monitoring for a stable distance reading. Once parked, the NeoPixels enter a "rainbow" animation mode before both the 7-segment display and NeoPixels power down.

The Board

This is the 2D and 3D representation of my board. Initially, I designed it with just the circular PCB, but in the final iteration, I incorporated an additional PCB dedicated to the ultrasonic sensor.

If you'd like to get started with PCB design, I have a step-by-step guide in "Tutorial No. 45: Transformers PCB BADGE", the link is in the description below.

Soldering

Lets starts by soldering the resistance to the board. Then lets solder the ESP32-C3 microcontroller to the board. Since I care a lot about my ICs and micro-controllers, I never solder them directly to the board. In case of an ICs, I always try to use IC bases or if a base is not available I use female pin-headers. (This avoids direct soldering and allows for easy replacement).

Then, let solder the buzzer followed by the AC-DC 5V Adapter to the board. Once thats done let solder the 7-Segment display to the board followed by the NeoPixel Ring. To maintain the height I added few supports to keep the ring affloat. 

The 220V power supply will be connected to these ports and the Ultrasonic sensor will connect to these ports via a 1M long cable.

Note: While a resistor isn't strictly required for WS2812 LEDs, it's often recommended to include one on the data line, especially for longer strips, to ensure reliable operation and protect the first LED from voltage spikes. A resistor between 220 ohms and 1k ohm is typically used.

3D Printing

I created the 3D model for this project using Microsoft 3D Builder. The top section is made up of four key components:

•   Main Housing – The primary enclosure for the unit.
•   Front Covers – Protective panels for the front section.
•   Internal Holder – A custom piece to secure the unit inside the housing.
•   Back Lid – The rear cover that completes the assembly.

For the bottom section housing the ultrasonic sensor, I used a 3D model originally created by dstark1 from Thingiverse, which I modified to fit into my project.

The 3D printed cover acts as a light-diffusing cover for the NeoPixel ring. Its semi-translucent material softens the bright LEDs, preventing eye strain and protecting the components.

Once all the 3D models were sorted, I went ahead and printed them using my 3D printer.

Assembly

To complete the setup, assemble the 3D-printed enclosure and insert the electronics into it. Mount the ultrasonic sensor on the garage wall at bumper height for accurate detection, and install the LED strip where it is clearly visible to the driver. Calibrate the system by testing with objects at known distances and adjust the SAFE_DISTANCE, WARNING_DISTANCE, and DANGER_DISTANCE values in the code accordingly. Finally, fine-tune the buzzer’s frequency and duration for optimal alerts.

Demo

When the unit boots up, the LEDs flash in rainbow colors and then switch to displaying a color based on the proximity. The distance is also shown on the 7-segment display. If no movement is detected, the LEDs and the 7-segment display turn off.

Beyond standard proximity detection, this version also includes Wi-Fi/Bluetooth connectivity, allowing smartphone integration to monitor distance data via Google Charts.

Let me know what you think. 

Feel free to like, share, and comment if you have any suggestions for improvement!

Key Features

Progressive visual feedback - LED color changes from green to red as distance decreases

Audible alerts - Beeping frequency increases as vehicle approaches obstacles

Weather-resistant - design for outdoor use

HC-SR04 Ultrasonic Sensor:

Maximum Range - 4 meters

Minimum Range - 2 cm

Thanks

Thanks again for checking my post. I hope it helps you.

If you want to support me subscribe to my YouTube Channel: https://www.youtube.com/@CrazyCoupleDIY

•   Video: https://youtu.be/rqTDj7GabGw
•   Full Blog Post: https://diyfactory007.blogspot.com/2025/08/arduino-parking-assistant-v3.html
•   Github: https://github.com/tarantula3/Arduino-Parking-Assistant-V3

  References

•   Arduino based parking assistant V1: https://youtu.be/LQGhprwuHe0
•   Arduino based parking assistant V2: https://youtu.be/MqJxUf3Cugg
•   All About TM1637: https://youtu.be/Ob9mrq_Lj9k
•   Transformers PCB BADGE: https://youtu.be/vlJoQAzjYDo

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