Project Hub /IoT & Connected Devices/Health Monitoring System/Build a Portable Step Counter using ATtiny85 and MPU6050

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ATTINY85

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

Build a Portable Step Counter using ATtiny85 and MPU6050

Build a portable, coin-cell powered pedometer using an ATtiny85 microcontroller, MPU6050 accelerometer, and an OLED display.

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.

MPU6050 - Triple Axis Accelerometer + Gyroscope Module Rs. 438.00
0.96 Inch I2C/IIC 4pin OLED Display Module White Rs. 349.00
2-Slot 18650 Holder with Protective Cover and On/Off Switch – Case Rs. 109.00
10pcs - 220 ohm 1/4 W Resistor Set Rs. 39.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

This list includes a generic resistor set as a placeholder — it is not matched to the exact value or part number this circuit needs. The correct one is specified on the original source page linked above; check it before buying.

We don't carry yet: Battery (generic / unspecified)
ATtiny
Custom PCB / PCB Fab

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How It Works

This portable step counter functions by integrating motion-sensing hardware with a low-power microcontroller system powered by a 3V coin cell battery. At the heart of the circuit is the MPU6050 sensor module, which uses a 3-axis accelerometer to continuously detect physical acceleration and movement dynamics as the user walks. The ATtiny85 microcontroller communicates with the MPU6050 and the OLED display module using the I2C protocol, facilitated by software libraries like TinyWireM. As the user moves, the ATtiny85 samples the accelerometer data, applies a step-detection algorithm to isolate acceleration spikes characteristic of footfalls, and updates the step count in its local memory. Two push buttons connected to the circuit allow the user to interact with the device, such as resetting the count or toggling display states. The processed data is then rendered graphically onto the OLED display module, providing real-time feedback of the user's physical activity. Because the entire system relies on a compact custom PCB, SMD 10KOhm pull-up resistors, and an energy-efficient ATtiny85 microcontroller, the circuit minimizes current draw, enabling practical portable operation from a single coin cell battery.

Why Build This

Design and optimize a battery-powered embedded system capable of low-power motion sensing suitable for wearable health devices.

Implement I2C communication protocols and custom algorithms on an ultra-constrained microcontroller architecture like the ATtiny85.

Integrate multiple peripheral modules—including an inertial measurement unit, an OLED display, and tactile user inputs—onto a compact custom PCB.

Real-World Application

Fitness tracking, portable activity monitors, wearable health devices, and low-power motion sensing.

Skills You'll Learn

I2C communication

accelerometer data processing

low-power microcontroller design

surface-mount component soldering

embedded display interfacing

step-detection algorithm implementation

Safety Precautions

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

Technology Tags

ATTINY85

MPU6050

OLED DISPLAY

I2C

ACCELEROMETER

PCB DESIGN

WEARABLE ELECTRONICS

C++

ARDUINO IDE

Frequently Asked Questions

How can the ATtiny85 communicate with multiple I2C devices when it lacks dedicated hardware pins?

The ATtiny85 uses software-based I2C implementation (often called USI or Universal Serial Interface) via libraries like TinyWireM, allowing it to communicate with both the MPU6050 and the OLED display over shared data and clock lines.

Why does the circuit use SMD 10KOhm resistors?

The 10KOhm resistors act as necessary pull-up resistors for the I2C bus lines, ensuring stable signal logic levels between the ATtiny85, the MPU6050, and the OLED display module.

Can a standard 3V coin cell battery provide enough current for both the display and the sensor?

Yes, provided the software utilizes low-power sleep modes and the OLED display is managed efficiently to avoid excessive continuous current draw, making coin-cell operation viable for short-term portable use.

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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