I'm quite blank when it comes to electronics, but am trying to learn...

So I bought a DIY Learning Kit from Banggood to get some solder practice.

As you can see from this video, the leds will change color and turn on and off in different patterns.

This question already establish that two pin RGB leds most likely contains some kind of micro chip, but it doesn't say anything about how they can be controlled.

The chip on the board is a STC15F204AE, and I guess that's the one responsible for creating the patterns. But again - how?

Is it just a fixed sequence pattern in the LED, and then the chip ensures that each LED receives power right after the previous, or is the LEDs addressable some how?

  • 1
    \$\begingroup\$ https://youtu.be/gxdgRHmOuIo has some insights. \$\endgroup\$ Commented Jan 16, 2017 at 5:35
  • \$\begingroup\$ That was a great video! With constant voltage, my LED will change color and turn on and off in a pattern, so I guess it's one of the cycling LEDs and not a pulsing LED as mentioned right in the start of the video. But I'll try to experiment a little with different voltages and pulses just in case. Thanks! \$\endgroup\$
    – Vegar
    Commented Jan 16, 2017 at 8:16

1 Answer 1


I'm afraid we're a smart about this as you are – for all we know (and as you know, from the answer you've linked to), the LED contains some controller itself. It might be controllable by shutting the supply voltage on and off, or by varying the input voltage.

The STC15F204AE is just a run-off-the-mill microcontroller – it was probably chosen for price reasons (it's not an established microcontroller brand, but uses the ancient, yet omnipresent 8051 CPU core architecture.) It executes some software (that we don't know) to send some commands (that we sadly don't know, either) to control the LEDs (which listen to some –unknown– form of commands).

  • \$\begingroup\$ But it would be theoretically possible to communicate with the led through just the power-pin? \$\endgroup\$
    – Vegar
    Commented Jan 15, 2017 at 14:05
  • \$\begingroup\$ It is, as you say it only has two pins, one has to be ground, one has to be supply, and thus, communication has to happen over one of these. OK, things like wireless communication or wireless energy transfer aside. \$\endgroup\$ Commented Jan 15, 2017 at 14:09
  • \$\begingroup\$ I take that as a 'yes', that it would be possible to control the color through the power-pin. some how. \$\endgroup\$
    – Vegar
    Commented Jan 15, 2017 at 15:09
  • 1
    \$\begingroup\$ Hm, I thought I said exactly that in my answer? \$\endgroup\$ Commented Jan 15, 2017 at 15:22
  • \$\begingroup\$ I tried putting power to a single led, and it shows that with a constant input voltage, the led will change color and turn on and off in a predefined pattern, so most likely, the chip will only time when each led gets it's power. Probably. \$\endgroup\$
    – Vegar
    Commented Jan 16, 2017 at 7:51

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