RGB LED Strip Kit – A Look Inside

Today’s topic is somewhat funny. It is a teardown of a Chinese RGB LED Strip Kit. This is an old kit I recently found on a dusty shelf. Let’s start with its unboxing.

This is a cheap RGB LED strip kit that features an infrared remote control that lets you choose between different modes and colors. As you can see in the pictures, the kit comes with the following components:

  • 12V/2A SMPS Plug-in Adapter (100-240VAC Input)
  • 3-Channel RGB LED Controller with Infrared Sensor
  • Infrared Remote Control Handset (Powered by CR1220 Lithium Cell)
  • 12V Flexible RGB LED Strip (5 meter/9 LEDs per every cuttable segment)

An annotated picture to make things less clouded…

And the overall wiring diagram:

If you are still interested enough, you should have a look at this. I’m going to take it apart. It also goes more in-depth on the electronics used in the RGB LED controller!

This is what I saw inside when I freed a couple of plastic locks to open the controller box. Interestingly enough, a single-sided little PCB which’s populated with all chip components. The only exception is the 2.1mm x 5.5mm DC power jack which is a regular thru-hole type.

Notice the vacant space next to the unknown 8-pin microcontroller. As clearly marked, it’s reserved for a 24C02 Serial EEPROM.

The microcontroller seems to be one of the PIC12F series as I can remember a few similar designs (more on this shortly). I created a schematic below for you.

Key parts are:

The 2835 (2.8mm x 3.5mm) RGB LED strip is a common-anode type – yes, you’ve guessed it. But note the LED strip has 330Ω series resistors for all LEDs.

This standalone RGB LED controller, as it seems, is based on a PIC12F675, PIC12F629, or PIC12F683 microcontroller. It is probably a loose adaptation of the RGB LED Mood Light project (http://picprojects.org.uk/projects/rgb2/index.htm#Code_Download).

The Si2302 MOSFETs are logic-level devices and are specified to operate with a very low gate voltage.

The 38kHz infrared remote control lets you choose different colors and modes to your liking. Else the software will keep changing colors in its own way.

As a final aside, let’s see how to use Raspberry Pi Pico (https://www.electroschematics.com/raspberry-pi-pico-first-look-part-1/) to easily test independent RGB LEDs/LED modules/LED strips!

The simple idea is to configure three GPIOs as three LED drive channels (GPIO16-18-20). The GND is common for all channels.

This is the code to run in the Thonny IDE (https://thonny.org/). When you run the code , it will ask where to save the code. You can save either in the computer or in the MicroPython device. If you save the code as “main.py” in the device, the code will run automatically even if you’re powering it later using a 5V/USB power supply adapter without connecting to the computer.

from machine import Pin

import time

led1 = Pin(16, Pin.OUT)

led2 = Pin(18, Pin.OUT)

led3 = Pin(20, Pin.OUT)

while True:

led1.value(1)

utime.sleep(1)

led1.value(0)

led2.value(1)

utime.sleep(1)

led2.value(0)

led3.value(1)

utime.sleep(1)

led3.value(0)

I tested this concept using a traffic light LED module (RYG) as it’s only handy at that time. Spoiler: It worked out fine! You can see a quick test video here https://www.youtube.com/watch?v=ZTdp0F6_0w8

Side note: I already used the same traffic light LED module on another project https://www.codrey.com/electronic-circuits/traffic-light-led-modules-lets-start/

As you would expect, LED strips cannot be run with this simple setup. You need to use three logic-level Power MOSFETs to accomplish that. I won’t go into it because you know how to do it.

RGB LED Strip Lights are becoming quite popular now a days, and these strips do come with several amazing features like programmable options for hassle-free functioning, music/voice modes to perfectly synchronize the light with music, smartphone apps for wireless control, etc.

I’m ready to dive into something interesting, and I’m hoping to find a few ways of making these cute things without too much work. Stay tuned!

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