How to Add an RGB Matrix Display to Your Board in Geppetto
Micro RGB Matrix Tile connected to the WiFi RGB LED Matrix board.
When it comes to custom display applications, you may not need to go the route of including a large-scale LED or LCD display screen. For specialized or artistic lighting applications, you can benefit from a system that provides selectable color mixing and distribution across your lighting module. This is where an RGB matrix display is an ideal choice for your next lighting application.
Gumstix recently released three new RGB LED display modules:
These three RGB display modules are based on digitally addressable Worldsemi WS2812B LEDs, more commonly known as Adafruit Neopixels. These RGB modules can be programmed with an Arduino-compatible board or COM using the Adafruit Neopixel library. Let’s take a look at each of these modules and how you can quickly add them to a new carrier board using Geppetto.
Designing Around the Micro RGB Matrix Tile
The Micro RGB Matrix Tile is a 16 x 16 RGB LED grid (256 LEDs total) in a densely-packed setting. Multiple RGB LED displays can be daisy-chained together and they easily connect to any microcontroller board. The Wordsemi WS2812B-2020 RGB LEDs used on this board have a refresh rate of 800 Kbps. The Micro RGB Matrix Tile is designed for applications requiring a high-resolution display, custom controller mode, and modular stacking.
Micro RGB Matrix Tile board.
Adding the Micro RGB Matrix Tile in Geppetto
The 5.6 cm x 5.6 cm Micro RGB Matrix Tile uses three primary connections:
- 2-pin DATA IN
- 2-pin DATA OUT
- 4-pin power port
Te DATA IN and DATA OUT ports allow you to connect this display to the controller digital port or another display port, respectively. The DATA OUT port is used for stacking another RGB matrix display using the 2nd display’s DATA IN port, creating a daisy chain network of LED modules. You can stack as many of these modules together until you run into processing, memory, or power constraints. Adding more modules requires adding more memory and a power regulator with a larger output.
Each RGB LED consumes approximately 80 mW, thus all 256 LEDs will consume at least 20.48 W of power. The module comes with an onboard Texas Instrument TP5450 step down converter. The power module can deliver 5 V/5 A from an input source ranging from 5.5 V to 36 V. You can immediately clone this RGB matrix display module into a new Geppetto project by going to the product page and clicking the Design Your Own button. This will bring up a new project in Geppetto that contains the RGB matrix display module and a power regulator.
Cloned Micro RGB Matrix Tile board in a new Geppetto project
Adding an ESP32U as a Controller
The image above shows the Micro RGB matrix display without any host controller. One option for a controller is an ESP32U. This controller requires 3.3 V of power, so we can add a 3.3 V/1.5 A power converter to the board. The Topmost left RGB LED in the matrix is used to configure the DATA IN connection. Here, we’ve connected the DATA IN is connected to the PWN_1H on the ESP32 microcontroller, as shown below.
Defining the DATA IN connection on a new Micro RGB matrix display board in Geppetto
After the connection is made, the entire board should turn green, indicating that there are no errors in the board design. To enable support for stacking other RGB LEDs on this board, the DATA OUT connection at the bottom right LED can be passed out through a 2-pin connector. Other components like sensors can also be added. I added a USB micro-B port so that I can program the ESP32 via USB. The USB micro-B port is connected to a a USB to UART converter, which is then connected to the ESP32 UART Download port. The final design of this modular, stackable RGB matrix display is shown below:
2D board layout (left) and 3D view of the finished RGB matrix display (right)
Adding the RGB Matrix Tile in Geppetto
The RGB Matrix Tile is similar to the Micro RGB Matrix tile. It is also a 16 x 16 RGB LED array that supports daisy-chaining. However, the RGBs used on this board are based on Worldsemi WS2812B-3535s LEDs. The display module comes with 2-pin DATA IN, 2-pin DATA OUT, and 4-pin power connections.
Just like the Micro RGB Matrix Tile, this display board can be added to any application using Geppetto. Just go to the product page and clone the existing design. The initial board will contain the LEDs and a 5 V/5 A power regulator. You’ll need to add a host controller if you want this RGB matrix display to function as its own product; this follows the same procedure presented for the Micro RGB Matrix Tile.
WiFi RGB LED Matrix
The WiFi-based RGB LED Matrix display uses a USB Type-C for power delivery, which is capable of delivering enough power to driver over 1000 RGB LEDs. The module also contains a WiFi MCU ATSAMW25 for controlling the LEDs. The ATSAMW25 can be easily programmed with the Arduino IDE. Geppetto's new USB Type-C power delivery module is capable of 100 W of power to a set of daisy-chained modules. The WiFi RGB LED Matrix display is meant to be an independent device as it already includes its own host-controller and power regulator.
You can also clone the WiFi RGB Matrix Tile display with Geppetto and add it to your modular board. First, just go to the product page and click the Design Your Own button. The initial cloned design is shown in the image below. Just like the Micro RGB Matrix Tile board, this cloned board can be expanded further by adding sensors, another RGB Matrix Tile module, another controller, and much more.
Cloned WiFi RGB LED Matrix board in Geppetto
RGB Matrix Display Design is Easy in Geppetto
No matter which of the above displays you want to use, Geppetto’s online platform allows you to design your customized board from a broad range of fully functional COMs and other hardware modules. These tools are available in a browser-based design interface that allows you to create fully functional modular hardware systems and quickly plan for production. It’s free to get started and experiment with any design you can imagine.