Project Hub /Test & Measurement Instrumentation/Sensors & Signal Measurement Tools/How to Interface Raspberry Pi Pico W with an Ultrasonic Sensor

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RASPBERRY PI

₹500 – ₹1,500

3 – 6 Hours

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How to Interface Raspberry Pi Pico W with an Ultrasonic Sensor

Learn how to connect an HC-SR04 ultrasonic sensor to a Raspberry Pi Pico W to measure distances and display the results on an optional OLED screen using MicroPython.

Originally published on CircuitDigest

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Raspberry Pi 3 - Model B+ 1.4Ghz 64-bit quad-core Processor with 1 GB Ram (Original) Rs. 9,810.00
Ultrasonic Sensor Module HC-SR04 Rs. 89.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
0.96 Inch I2C/IIC 4pin OLED Display Module White Rs. 349.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

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How It Works

The Raspberry Pi Pico W interfaces with an HC-SR04 ultrasonic sensor to calculate distances using sound waves and timing principles. Under the control of a MicroPython script running in the Thonny IDE, the Pico W sends a short trigger pulse to the ultrasonic sensor. Upon receiving this signal, the HC-SR04 emits an 8-cycle burst of ultrasound at 40 kHz. When these sound waves encounter an obstacle, they bounce back as an echo. The sensor detects this reflected wave and outputs an echo pulse whose duration corresponds directly to the round-trip travel time of the sound. The Raspberry Pi Pico W measures the exact length of this incoming pulse using its digital input pins. By applying the known speed of sound through air, the microcontroller computes the distance between the sensor and the target object. If the optional OLED screen is included in the circuit, communication is established via I2C, allowing the Pico W to transmit the calculated distance data and render it visually on the display for real-time tracking.

Why Build This

Design and prototype a functional smart parking or robotic obstacle-avoidance feedback loop using physical computing hardware.

Implement automated liquid level monitoring or non-contact proximity detection systems suitable for industrial instrumentation.

Practice reading, processing, and displaying asynchronous sensor data metrics using an embedded microcontroller running MicroPython.

Real-World Application

Distance measurement, smart parking systems, obstacle detection for robotics, and automated liquid level monitoring.

Skills You'll Learn

Microcontroller digital input and output control

pulse-width timing measurement

I2C peripheral communication

sensor data processing

visual display interfacing

Safety Precautions

No specific precautions noted for this build — always follow general electronics safety practices.

Technology Tags

MICROPYTHON

ULTRASONIC SENSOR

HC-SR04

OLED DISPLAY

DISTANCE MEASUREMENT

IOT

PROTOTYPING

Frequently Asked Questions

Can I power the HC-SR04 sensor directly from the Pico W's 3.3V pin?

While the HC-SR04 can technically operate at 3.3V, it is designed for a 5V supply and may yield weaker trigger and echo responses on lower voltages; check your specific sensor module specifications to determine if a 5V VBUS connection with level shifting on the echo pin is required to protect the Pico W's 3.3V inputs.

Why is an optional OLED screen useful in this setup?

The OLED screen provides a local, real-time visual output of the measured distance, allowing you to read sensor data immediately without needing to keep the Pico W tethered to the Thonny IDE terminal.

What happens if the ultrasonic sensor does not detect any returning echo?

If no obstacle is within range to reflect the sound wave, the echo pin will time out, and your MicroPython code must be written to gracefully handle this timeout to prevent the program from freezing.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

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