I Built a Parking Sensor on ESP32 in 1 Minute — Day 5/100

The brain of this build is the HC-SR04 ultrasonic sensor. Four pins: VCC, GND, TRIG, and ECHO. The two metal cylinders are a transmitter and a receiver. The transmitter fires a burst of ultrasonic sound, the
receiver catches the reflection. Time the round trip, do the math, get distance.

Same ESP32 board from yesterday's project, with HC-SR04 wired in, plus an OLED screen and a piezo buzzer kept from the previous wiring. Flash the code, and we're live.

Closer the obstacle → faster the beeps → bigger the bar on the OLED.

## Hardware

• ESP32 dev board
• HC-SR04 ultrasonic sensor
• 0.96" SSD1306 OLED (I²C)
• Piezo buzzer
• Breadboard + jumper wires

## Wiring

OLED SDA → GPIO 22
OLED SCL → GPIO 23
OLED SDA → GPIO 22
OLED SCL → GPIO 23
Buzzer (+) → GPIO 18 (LEDC PWM)
HC-SR04 TRIG → GPIO 5
HC-SR04 ECHO → GPIO 4 (with 1k/2k voltage divider — ECHO is 5V, ESP32 is 3.3V)

## Code logic

• Sample every 60 ms, EMA-smooth the reading
• 0–5 cm: solid tone (STOP!)
• 5–12 cm: fast beeps (CLOSE)
• 12–20 cm: slow beeps (WARN)
• 20 cm: silent (SAFE)

100 days of electronics from zero. New project every day for 100 days.

00:00 The HC-SR04
00:10 How ultrasonic works
00:25 Wiring and flashing
00:40 Live test
00:50 Subscribe — Day 6 tomorrow
Previous: Day 4 — ESP32 crypto price ticker
Next: Day 6 — temperature + humidity sensor
#esp32 #arduino #electronics #diy #maker #engineering #stem

Видео I Built a Parking Sensor on ESP32 in 1 Minute — Day 5/100 канала EfimTech