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Tutorials

Building a Simple USB Flashlight

Overview​

This tutorial will walk you through building a simple USB flashlight using tscircuit. The circuit takes 5V from a USB-C connector, routes it through a pushbutton, and lights an LED through a current-limiting resistor.

What You Will Build​

The finished board has four parts:

  • a USB-C connector for power input
  • a normally-open pushbutton for user control
  • a resistor to limit LED current
  • a red 0603 LED as the light source

Circuit Requirements​

This small flashlight needs to:

  • connect USB VBUS to the button input
  • connect the button output to the LED through a resistor
  • return the LED cathode to USB ground
  • keep the board narrow enough to behave like a small USB accessory

Building the Circuit Step by Step​

Step 1: Add the USB-C Power Input​

Start with a small board and place the USB-C connector near one end. The VBUS pins provide the 5V rail and the GND pins provide the return path.

Schematic Circuit Preview

Step 2: Add the Pushbutton​

The pushbutton sits between USB VBUS and the resistor. Pressing it completes the positive side of the LED circuit.

Schematic Circuit Preview

Step 3: Add the LED and Current-Limiting Resistor​

The resistor protects the LED by limiting current. A 1k resistor is a safe, conservative value for a small indicator-style USB flashlight.

Schematic Circuit Preview

Final Notes​

Use the 3D preview to check that the connector, button, resistor, and LED are spaced comfortably on the board. For a brighter flashlight, lower the resistor value after checking the LED's current rating and the available USB power.