Project Hub /Automotive EV & Transportation/Smart Vehicle Safety & ADAS/LED Light For Bikes To Improve Visibility

Beginner

ATTINY85

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

LED Light For Bikes To Improve Visibility

An inexpensive and easy-to-make LED bike headlight featuring both a steady glow and an adjustable strobe light option to improve road visibility.

Originally published on ElectronicsForU

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.

10pcs 5mm RED Diffused Light Emitting Diodes - LEDs Set Rs. 39.00
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: Arduino (unspecified board)
Transistors (BC547 / 2N2222 / TIP / MOSFET)
Potentiometer / Trimpot
Capacitors
9V Battery + Snap
Header Pins / Terminals / Connectors

Browse all components

How It Works

The core of this bicycle visibility system is the Digispark ATtiny85 microcontroller board, which acts as the central processing unit to control the lighting modes. Power is supplied by a 9V USB rechargeable battery connected via a 2-pin connector, with a 220µF electrolytic capacitor placed across the power rails to help stabilize voltage fluctuations. To drive the high-power 1-watt star white LEDs safely without overloading the microcontroller's limited digital output current capacity, an IRL520N N-channel MOSFET is employed as an electronic switch. The ATtiny85 sends control signals to the gate of the MOSFET, utilizing a 10k resistor as a pull-down and a 100-ohm resistor for gate current limiting to protect the I/O pins from high inrush currents caused by MOSFET gate capacitance. A 10k potentiometer is integrated into the circuit as an analog input device, allowing the microcontroller to read varying voltage levels and dynamically adjust the operational state between a steady beam and an adjustable strobe lighting pattern.

Why Build This

Design and implement a practical power-switching circuit using a MOSFET to drive high-wattage LEDs from a low-power microcontroller.

Utilize analog-to-digital conversion by interfacing a potentiometer to dynamically control lighting output frequencies or modes.

Deploy a functional, microcontroller-based safety device optimized for low-visibility cycling conditions.

Real-World Application

Mounted on bicycles as a headlight to ensure the rider is visible to other vehicles and pedestrians at night or in foggy conditions, while also providing enough illumination to see obstacles on the road.

Skills You'll Learn

MOSFET power switching

microcontroller I/O interfacing

analog sensor reading with potentiometers

LED driver circuit design

power supply decoupling

Safety Precautions

Ensure correct polarity when connecting the battery. Use appropriate gate resistors (R1 and R2) to protect the microcontroller I/O pins from high inrush currents originating from the MOSFET gate capacitance.

Technology Tags

MICROCONTROLLER

ATTINY85

LED

STROBE LIGHT

MOSFET

POWER REGULATION

POTENTIOMETER

BIKE LIGHTING

Frequently Asked Questions

Why is an IRL520N MOSFET used instead of driving the 1-watt LEDs directly from the ATtiny85?

The ATtiny85 microcontroller pins can only source or sink a small amount of current, which is far too low to drive a high-power 1-watt star white LED. The MOSFET acts as a heavy-duty electronic switch controlled by the microcontroller to handle the higher current safely.

What is the purpose of the 10k potentiometer in this circuit?

The potentiometer acts as an adjustable voltage divider connected to the ATtiny85, allowing you to manually vary an analog input signal used to control the strobe frequency or lighting mode.

Can I use a standard 9V alkaline battery instead of a 9V USB rechargeable battery?

While the voltage is the same, 1-watt LEDs draw significant current, and standard alkaline 9V batteries deplete very quickly under such loads. A rechargeable USB 9V battery is recommended for sustained performance and cost-effectiveness.

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.

PRJ-00451