Diving into the o28 LED Matrix

Having the LED matrix in SIGNAL mode unleashes some really fun features! littleBits’ engineers have programmed 5 presets onto the LED matrix, so you can play with the Bit right out of the box. In this post, we’ll be covering how to use the 5 presets, what they do, and how to make the most of them.


Before we get into what each preset does, let’s take a look at the Bit itself. You’ll notice that the o28 LED matrix has 3 bitSnaps: the input bitSnap, the input auxiliary bitSnap, and the output bitSnap. The first input bitSnap controls one aspect of each preset, like brightness or location; while the auxiliary input controls another, like color or location. The output bitSnap connects to other Bits in a circuit.

You’ll need input Bits on both input bitSnaps to fully control the presets on the LED matrix. Keep in mind, you’ll need a powerSnap on the auxiliary input to get it to work properly. We’ll get into what each preset does in the next section.


When you switch the mode of the o28 LED matrix to SIGNAL, pressing the button labeled PRESETS will cycle the LED matrix through Color Wheel, X-Y, Draw, Spectrum, and Scoreboard. The default preset is Color Wheel. However, if you select any preset and power-off, then power-on the LED matrix, it will return to the last preset used.

The presets are represented by icons. Each icon appears on the display for ~1 second every time you press the PRESETS button. When the icon turns off, the LED matrix is set to that preset.


Icons Example Name Description Main Input Aux Input
    Color Wheel All LEDs on the screen display the same color. Sets LED brightness Sets LED color
    Spectrum Mimics an audio visualizer and displays the frequency spectrum of the input signal. Signal source being visualized Color scheme
    X-Y Lights a single white LED that moves around the screen. The position is controlled by using inputs on the 2 input bitSnaps. X location Y Location
    Scoreboard Shows two numbers that increment up. Each number increases from 0-9, and resets to 0 after 9. Increments player 1 score, in red Increments player 2 score, in white
Draw Sets the colors on the screen pixel by pixel to draw an image. The input Bits select the pixels and colors. Cursor for which pixel you are changing Change color



Coding with the LED matrix in SIGNAL mode opens up a whole new world of possibilities. You can take advantage of the [LOOPS], [MATH], and [SEND SIGNAL] blocks to code some really cool effects.



SERIAL mode gives you total control over the display on the LED matrix. While in SERIAL mode, the LED matrix will display any custom images and scrolling text you make. Use the [IMAGES] blocks in the app to send colors and pictures to the matrix, and the [TEXT] blocks to send messages. Just make sure that the LED matrix is snapped to OUT 1 on the codeBit.

While playing around with the LED matrix Bit, you might notice that pressing the PRESETS/CHANNEL button makes a 1 show up on the matrix. This 1 refers to the channel on which the LED matrix receives data. All LED matrices default to channel 1, and will all show the same image if you snap them in line with each other. littleBits’ engineers are working on making 4 channels available for each LED matrix, which will be useful when tiling your matrices.


The case around each LED matrix has dimples and magnets. These features are super helpful when you’re using multiple matrices.The dimples help you position the displays correctly, and the magnets keep them from separating. You’ll notice that the cases snap together when they’re in the correct position, and push apart when they’re not – like the Bits themselves!


If you’ve ever wished that the LED matrix could be bigger, tiling is the answer. The multi-tile feature allows you to combine up to four LED matrices together to form a larger display that you can use in your games and animations. 

Use the new multi-tile feature to arrange your matrices in any of the following formations:

Tiling with 2 Matrices

Tiling with 3 Matrices

Tiling with 4 Matrices


Multi-tile is an advanced feature and is only available in the “blank canvas” screen. To set up the multi-tile feature on your computer, open up a blank canvas screen and follow the instructions in the multi-tile panel on the blank canvas screen.

Step 1: Decide on the number of matrices that you plan to use and choose that number from the drop-down menu.

Multi-tile: Step 1

In this example, I am going to tile four matrices, so I have chosen “4 Matrices” from the drop-down menu.


Step 2: Figure out how you plan to arrange your matrices and click on that arrangement.

Multi-tile: Step 2

In this example, I have chosen the 2×2 arrangement. Once you’ve selected an arrangement, any matrix blocks that you have dragged out to your canvas should change to match the arrangement you’ve selected.

Step 3:
Connect your LED matrices to OUT1 of the codeBit, all in a row and arrange them in the same formation that you chose in step 2.

In this example, I have attached 4 matrices to OUT1 of the codeBit and have organized the four matrices into a 2×2 grid. (Note: The matrices have magnets and dimples on each side that allow them to snap together.)

Step 4:
Connect your codeBit and upload your multi-tile arrangement and code to your codeBit.

Step 5:
Press the CHANNELS button on each LED matrix until the number displayed matches the image in the window.


We’ve included solutions to common questions below.

  • What happens to my multi-tile settings if my circuit is disconnected from power?

    If you have already uploaded a multi-tile image to your codeBit and your circuit is disconnected from power, you will need to reconnect power to your circuit and update the channels on each LED Matrix Bit.


  • What happens to my multi-tile settings if any of my LED matrix Bits are disconnected from the codeBit? 

    If any of your led matrix Bits is unplugged from your codeBit, you will need to reconnect all of your LED matrix Bits to the codeBit, upload your code again, and update the channels on each of your LED matrix Bits.


  • What happens to my multi-tile settings if I rearrange my tiles?

    If you rearrange the your LED matrix tiles, but keep the same number of tiles in your arrangement, (like going from 4 matrices in a 1×4 arrangement to 4 matrices in a 2×2 arrangement,) your drawing will be rearranged, but nothing will be lost.

    However, if you remove any of your LED matrix Bits, (like going from 4 matrices in a 2×2 arrangement to 2 matrices in a 1×2 arrangement,) you will lose a part of your drawing and won’t be able to undo it.


  • Are all of the blocks compatible with multi-tile?
    There are a few blocks that aren’t yet compatible with multi-tile: 

    • [ SEND [ COLOR ] PIXEL AT X: [ 0 ], Y: [ 0 ] TO [OUT1] ]
    • [ ADD [ COLOR ] PIXEL AT X: [ 0 ], Y: [ 0 ] TO [ IMAGE ] ]
    • [ SEND IMAGE [ ] ROTATED [ 90 ] TO [ OUT1 ] ]
    • [ ROTATE [ IMAGE ] BY [ 90 ] ]

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