We control computer RGB lighting without a PC

The name ARGB or Addressable RGB literally speaks for itself. Instead of stupid control of three lines as in simple strips, addressable RGB LEDs are installed here. Their trick is that the diode has the same 4 contacts, 2 of which are power, and 3 and 4 are data input and data output. Each “pixel” is not just an LED, but an entire structure with a microcontroller, as well as three LEDs of red, green and blue.

All the “diodes” stand in line and transmit data further along the chain, at the same time they themselves take data from the data packet and apply the selected color to themselves. The data packets are very compact, packing brightness (256 values) and 16,777,216 colors. All this is transmitted over the chain at speeds of up to 800 kbit/sec!

Such strips with diodes are connected to the motherboard via a simple 3-pin connector. Through them, the tape receives 5V power, as well as data.

The low supply voltage of these diodes is at the same time their strong point if they are powered, for example, from USB, but also their weak side, since each diode can consume up to 60 mA, and the tapes can be long and with a large number of diodes, and the tape substrate itself is often thin and soft for the sake of convenience. As a result, installations with a large number of diodes can greatly sag in brightness and distort color at a great distance from the beginning of the tape. But in the case of computer hardware, this situation is quite rare.

Showdown

Everything said above about addressable diodes is only a theory; in practice, manufacturers can install literally anything in their devices, as long as it is compatible with the protocol used in ws2812 chips. In addition, the ws2812 itself can be either a bare chip installed in the LED housing, or a discrete chip that controls the diodes via mosfets.

For this post, Adata XPG provided XPG Huricane 120 ARGB fans as well as Xpg Prime ARGB cable extensions. We will analyze them in search of addressable LEDs, and also connect them to our microcontroller bypassing the motherboard with its native software.

First up was the XPG Huricane 120 ARGB fan. The diodes are located in two places at once. On the “hub” of the motor, as well as in the form of a ring around the impeller.

Remove the black ring that holds the white diffuser in the fan, and then pull out the white diffuser with a screwdriver.

After removing the diffuser, you can take out the tape.

At first glance, the diodes are ordinary, exactly the kind that can be found in datasheets.

Upon closer inspection we find the same WS2812 chip.

Things get a little more interesting with the Xpg Prime ARGB Extender Cables. The backlight design is very compact and the diodes in the 5050 case simply won’t fit there. Disassembly showed that very tiny SMD diodes of 2020 size are installed here! They were found in China under the name “WS2812-2020”

Each diode inside actually has 3 LEDs as well as a Ws2812 compatible chip, which allows you to control the lighting of each decorative tube.

But how do you manage such tapes?

In practice, everything is as simple as possible. We will need any microcontroller, either Arduino, stm32, or the cheapest solution on the market – ESP8266 or ESP32. I decided to take the esp8266 as an example of a cheap controller with the ability to flash your own code.

First, let's solder the connector for addressable tapes. I found a plug from a 4pin RGB strip; to work with 3pin, you just need to bite off one cable and a pin from a male-type plug. If you don’t have such a plug, you can bite it off from one of the fans, the solution is not ideal, but who’s going to stop you?

I chose the ESP8266 by Wemos D1 mini as the controller. It is ideal for its low price of around 200 rubles, as well as its compact design and USB-TypeC connector which will allow you to connect this board with a modern cable to any PC.

I soldered the strip power to the 5V pin, ground to G, and the signal cable to the D4 port. It is advisable to install a 220-440 Ohm resistor between the tape and D4, but even without a resistor everything will work without problems.

Now I will show you the simplest way to start managing arb devices – WLED firmware. To work with it, you do not need programming knowledge or any knowledge at all. Just go to the website of the online flasher – https://install.wled.me/ select the latest firmware version, and connect the esp8266 board to the PC.

The drivers should pick up on their own, and a new COM port will appear in the system. Click INSTALL on the page and select the COM port that appeared when connecting the ESP.

If everything is done correctly, the site will offer to install the firmware, click INSTALL WLED and wait for the installation to complete, which takes about 1 minute.

After successful installation, you can immediately enter your login and password for your home Wfi network in order to control the device from a browser or from the WLED mobile application. If you do not configure the connection to the network, the board itself will raise its own network called WLED, and when connected to it, you can control the tape without having a home wifi network at all.

After successful installation of the firmware, you can connect controlled devices (fans, tapes, etc.) to the board and check. They will turn on immediately and glow orange at half brightness.

Next, go to settings (gear on the top right), then to led Preferences.

Let's set the current. In the case of USB3, it is worth setting the current to 0.9A or 900mA. But in practice, I have not come across motherboards that do not draw less than 1.5-1.9A. Let me remind you that a regular LED on a ws2812 chip will consume up to 60mA, but only if you turn on the white color at maximum brightness! In this case, we can calculate that at 1A we have a budget for as many as 16 LEDs, and at 2A there are already 32 LEDs. In practice, if you use wled effects or choose some color other than white, the total consumption of diodes can be divided several times

You also need to set the Number of diodes per channel. If you set it less, then the unused diodes will either not light up, or when turned on they will take on a random color and remain stuck. The number of diodes must be selected for a specific case. For example, my XPG Hurricane fans have 12 LEDs. If you connect all the fans in parallel, then in the wled settings it is enough to set 12 diodes. Passthru connectors of these fans are parallel, so there is simply no need to increase the number of diodes with each connected fan.

If your fans support daisy chain connection, then accordingly it is worth setting the number of diodes equal to the number of fans multiplied by the number of diodes in each fan. For example, 4 fans with 12 diodes each will give us a total of 48 diodes, this is the number that needs to be entered in the length settings.

After the settings, go to the main page, turn on the rainbow effect, and enjoy the RGB lighting that works without moms, dads, and crooked software from the motherboard!

All my Xpg hurricane fans have a passthru port, but it is parallel, so by setting 12 LEDs in the WLED settings, all 4 fans got the same backlight.

Extension cords for wires were also connected there along the chain. With special effects settings, you can get different colors on each cable tube.

WLED has excellent integration into a whole list of home automation software, such as Home assistant, Domoticz, MQTT and openHAB. Out of the box it supports integration with Amazon Echo, Philips Hue sync, etc. https://kno.wled.ge/advanced/home-automation/ Therefore, integrating computer lighting into a smart home will not be difficult.

In addition, there is an excellent API that allows you to control color and effects through simple HTTP requests or JSON https://kno.wled.ge/interfaces/http-api/ For faster communication, you can send the same json requests but via websockets https://kno.wled.ge/interfaces/websocket/

Fans of working with professional concert equipment will appreciate integration with DMX and Art-Net https://kno.wled.ge/interfaces/e1.31-dmx/

This is how you can easily and with a minimal budget control computer components with addressable RGB backlighting.