Make a display for your display! Show off your message to the world. This guide will show how to set up and assemble a Matrix Portal and RGB Matrix display, then make a transparent pocket in your backpack, purse, or messenger bag to show it off.

There is also a simple code example that displays your bmp images in slideshow fashion. Use the onboard buttons to switch between folders and play different messages, or pause on your favorite image. Set your bag down and the onboard accelerometer will sense that you're not moving and dim the screen to save battery life.

You can also use any of the other Matrix Portal code samples to get you started. Get ready to have fun with all the features the Matrix Portal offers.


The build for this project is really easy. For the electronics setup you'll just need a screwdriver. For the handbag mod, we'll use fabric scissors and glue to affix our vinyl window. Sewing skills could be helpful, but are not required.

The coding portion is a little trickier, but I've made it as simple as possible to get images flashing up on your screen. There are more and more guides in the Adafruit Learning System every day with sample code, so this project can get as involved as you'd like.

Parts Needed

The Matrix Portal board is a very cool microcontroller that plugs into the back of any of our RGB Matrix display panels. The displays come in lots of different sizes - check them out here.

I used the 4mm pitch 64x32 sized one for this project. It measures 10' x 5', and it fits perfectly inside the outer pocket of my pack. 

Video of a person rotating an LED matrix panel with animation resembling falling colored sand.
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Vide of assembled and powered on 64x32 RGB LED Matrix Panel - 4mm pitch. The matrix displays "Black Lives Matter" alongside the Raised Fist.
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Angled shot of a blue long rectangular USB battery pack.
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This lipstick-sized USB battery will power the Matrix Portal for a few hours (depending on the brightness of your images). We've also got a bigger one if you want it to last all night.

Angled shot of white rectangular USB battery pack with 4 dotted lights indicating battery is fully charged.
A large-sized rechargeable battery pack for your Raspberry Pi (or Arduino, or
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This board connects with a USB C cable, so get at least one of these.

1 x USB C Cable
USB C 6" Cable

You can unplug the cable to turn it off, but it's easier and handier to plug in an on/off switch.

1 x On/Off Switch
USB Cable with Switch

Additional Materials

You'll also need a backpack, messenger bag, or purse with a pocket that will comfortably fit your RGB display, with a couple inches extra on the "long" side to accommodate the Matrix Portal board and the USB cable.

I found the pack I'm using in this guide in the travel section at Target.

For the window, you'll need a square of vinyl. You can find this online or at your local plastic store. I used iridescent vinyl, which does make the matrix a little harder to see in the daytime, but it's shiny and iridescent so I don't really care -- and the matrix still shows through beautifully in lower light. The iridescence also gives my images a bit of a rainbow sheen, which I count as a win.

I also used a bit of Fray Check on my bag. This is a great product that you can find at sewing stores or online. Just apply it to the cut edges of your fabric and it will keep the fabric from unraveling. I always have some of this stuff handy.

This guide was first published on Oct 21, 2020. It was last updated on Apr 20, 2024.

This page (Overview) was last updated on Mar 08, 2024.

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