LED / Strip
Controlling RGB LED Module LED / Strip with Arduino Uno
What is the RGB LED Module?
RGB LED Module practical reference
A basic 4-pin RGB LED breakout used for teaching PWM color mixing and simple status-indicator projects.
Key specifications
- Type: Common-cathode on most breakout modules (common-anode variants also exist — verify with a multimeter before wiring)
- Forward voltage: ~2V (Red), ~3.2V (Green), ~3.2V (Blue), typical
- Control: 3 independent PWM channels, one per color, each through its own current-limiting resistor
- Current-limiting resistor: ~220Ω-330Ω per color channel at 5V logic — a shared value across R/G/B works fine even though forward voltages differ slightly
Pinout and connection notes
On a common-anode module, drive each color LOW to turn it on rather than HIGH — inverted from the common-cathode wiring most beginner tutorials assume.
- R: Red channel — through a current-limiting resistor to a PWM pin
- COM: Common cathode (to GND) or common anode (to VCC), depending on your specific module
- G: Green channel — through a current-limiting resistor to a PWM pin
- B: Blue channel — through a current-limiting resistor to a PWM pin
Integration checklist
- Confirm the exact part number and breakout-board revision.
- Verify supply voltage, current demand, logic levels, and signal direction against the datasheet.
- Check controller pin assignments and bus address or interface mode against the example code.
- Power up with external loads disconnected, then test signals before full integration.
- If readings or communication fail, check power and ground first, then pin mapping, interface settings, and library initialization.
Troubleshooting and reproducibility
Record the board used, wiring, library/version, supply arrangement, and measured behavior. Use the selected board-specific wiring example as the source of truth. Never assume visually similar modules share identical voltage tolerance or pin order.
Setting Up RGB LED Module with Arduino Uno
Library
None — built-in analogWrite by —
No library needed; uses core PWM functions.
Wiring
| Component pin | Arduino Uno pin | Note |
|---|---|---|
| R | D9 | PWM pin — series resistor usually already on the breakout module. |
| G | D10 | PWM pin. |
| B | D11 | PWM pin. |
| COM | GND / 5V | GND for common-cathode modules, 5V for common-anode — check your specific board. |
Swipe sideways to see every column →
- Common-cathode vs common-anode is the single most common gotcha here — if all your colors look inverted (white when you asked for black, etc.), you have the wrong COMMON_CATHODE setting for your specific module.
- Bare 4-leg RGB LEDs (not on a breakout board) need a current-limiting resistor per color leg (~220Ω) — breakout modules usually already include these.
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