Keep up to date on the current Bitcoin price index with this large matrix display

This project displays the current value of Bitcoin in one of three currencies -- USD, Euros, or GBP -- and displays it on a large, stylish RGB LED matrix display. All made in CircuitPython running on the Matrix Portal or the Metro M4 Airlift accessing the Coindesk API wirelessly!

Parts

Folks love our wide selection of RGB matrices and accessories, for making custom colorful LED displays... and our RGB Matrix Shields...
Out of Stock
Give your next project a lift with AirLift - our witty name for the ESP32 co-processor that graces this Metro M4. You already know about the Adafruit Metro...
$34.95
In Stock
Bring a little bit of Times Square into your home with this sweet 64 x 32 square RGB LED matrix panel. These panels are normally used to make video walls, here in New York we see them...
$39.95
In Stock
Our RGB matricies are dazzling, with their hundreds or even thousands of individual RGB LEDs. Compared to NeoPixels, they've got great density, power usage and the...
$5.95
In Stock
A nice whoppin' slab of some lovely black acrylic to add some extra diffusion to your LED Matrix project. This material is 2.6mm (0.1") thick and is made of special cast...
$9.95
In Stock
Our all-in-one 5V 2.5 Amp + MicroUSB cable power adapter is the perfect choice for powering single-board computers like Raspberry Pi, BeagleBone, or anything else that's...
$8.25
In Stock
This here is your standard A to micro-B USB cable, for USB 1.1 or 2.0. Perfect for connecting a PC to your Metro, Feather, Raspberry Pi or other dev-board or...
$2.95
In Stock

You can build this project with an all-in-one Matrix Portal board, its definitely the easiest and least-expensive way to go about it.

You will need a matrix portal, matrix, and USB C power/data cable

Folks love our wide selection of RGB matrices and accessories, for making custom colorful LED displays... and our RGB Matrix Shields...
Out of Stock
Bring a little bit of Times Square into your home with this sweet 64 x 32 square RGB LED matrix panel. These panels are normally used to make video walls, here in New York we see them...
$39.95
In Stock
As technology changes and adapts, so does Adafruit. This  USB Type A to Type C cable will help you with the transition to USB C, even if you're still...
$4.95
In Stock

CircuitPython is a derivative of MicroPython designed to simplify experimentation and education on low-cost microcontrollers. It makes it easier than ever to get prototyping by requiring no upfront desktop software downloads. Simply copy and edit files on the CIRCUITPY drive to iterate.

Set up CircuitPython Quick Start!

Follow this quick step-by-step for super-fast Python power :)

Further Information

For more detailed info on installing CircuitPython, check out Installing CircuitPython.

Click the link above and download the latest UF2 file.

Download and save it to your desktop (or wherever is handy).

Plug your MatrixPortal M4 into your computer using a known-good USB cable.

A lot of people end up using charge-only USB cables and it is very frustrating! So make sure you have a USB cable you know is good for data sync.

Double-click the Reset button (indicated by the green arrow) on your board, and you will see the NeoPixel RGB LED (indicated by the magenta arrow) turn green. If it turns red, check the USB cable, try another USB port, etc.

If double-clicking doesn't work the first time, try again. Sometimes it can take a few tries to get the rhythm right!

You will see a new disk drive appear called MATRIXBOOT.

 

Drag the adafruit_circuitpython_etc.uf2 file to MATRIXBOOT.

The LED will flash. Then, the MATRIXBOOT drive will disappear and a new disk drive called CIRCUITPY will appear.

That's it, you're done! :)

Power Prep

The MatrixPortal supplies power to the matrix display panel via two standoffs. These come with protective tape applied (part of our manufacturing process) which MUST BE REMOVED!

Use some tweezers or a fingernail to remove the two amber circles.

Power Terminals

Next, screw in the spade connectors to the corresponding standoff.

  • red wire goes to +5V 
  • black wire goes to GND

Panel Power

Plug either one of the four-conductor power plugs into the power connector pins on the panel. The plug can only go in one way, and that way is marked on the board's silkscreen.

Board Connection

Now, plug the board into the left side shrouded 8x2 connector as shown. The orientation matters, so take a moment to confirm that the white indicator arrow on the matrix panel is oriented pointing up and right as seen here and the MatrixPortal overhangs the edge of the panel when connected. This allows you to use the edge buttons from the front side.

 

Check nothing is impeding the board from plugging in firmly. If there's a plastic nub on the matrix that's keeping the Portal from sitting flat, cut it off with diagonal cutters

For info on adding LED diffusion acrylic, see the page LED Matrix Diffuser.

If you have a Metro M4 AirLift, you can build this project easily - you just need an RGB Matrix shield to help connect!

You will need a Metro M4 Airlift, matrix shield and matrix

Give your next project a lift with AirLift - our witty name for the ESP32 co-processor that graces this Metro M4. You already know about the Adafruit Metro...
$34.95
In Stock
Our RGB matricies are dazzling, with their hundreds or even thousands of individual RGB LEDs. Compared to NeoPixels, they've got great density, power usage and the...
$5.95
In Stock
Bring a little bit of Times Square into your home with this sweet 64 x 32 square RGB LED matrix panel. These panels are normally used to make video walls, here in New York we see them...
$39.95
In Stock

CircuitPython is a derivative of MicroPython designed to simplify experimentation and education on low-cost microcontrollers. It makes it easier than ever to get prototyping by requiring no upfront desktop software downloads. Simply copy and edit files on the CIRCUITPY drive to iterate.

Set up CircuitPython Quick Start!

Follow this quick step-by-step for super-fast Python power :)

Further Information

For more detailed info on installing CircuitPython, check out Installing CircuitPython.

Click the link above and download the latest UF2 file.

Download and save it to your desktop (or wherever is handy).

Plug your Metro M4 into your computer using a known-good USB cable.

A lot of people end up using charge-only USB cables and it is very frustrating! So make sure you have a USB cable you know is good for data sync.

Double-click the Reset button next to the USB connector on your board, and you will see the NeoPixel RGB LED (indicated by the arrow) turn green. If it turns red, check the USB cable, try another USB port, etc.

If double-clicking doesn't work the first time, try again. Sometimes it can take a few tries to get the rhythm right!

You will see a new disk drive appear called METROM4BOOT.

 

Drag the adafruit_circuitpython_etc.uf2 file to METROM4BOOT.

The LED will flash. Then, the METROM4BOOT drive will disappear and a new disk drive called CIRCUITPY will appear.

That's it, you're done! :)

Assembly

Talking to an LED matrix display can be tricky! The 64 x 32 LED used here has a whopping 2,048 pixels, and each can display RGB colors, which makes for a whole lot of data to sling around. Thankfully, our RGB Matrix shield paired with the Metro M4 Airlift does most of the heavy lifting.

Let's assemble the boards and the display so we can get things running!

Shields Up

First, add the male headers, screw terminal block, and the 8x2-pin socket to the Matrix shield, by following this guide. Be careful to match the socket polarity to the silkscreen image on the board.

Be sure to also perform the clock pin mod as shown here.

Then plug the shield into the Metro M4 Airlift.

Power Connections

To provide power, we'll screw the wiring harness connectors to the screw terminal blocks of the shield. Be sure to match the black wire to GND and the red wire to +5Vout.

Now, simply plug the other end into the panel's power header. It can only go in one way.

Data Cable

Plug in the two ends of the ribbon cable, note that the connectors are keyed to only fit in the correct orientation.

Wall Adapter

We'll power the Metro M4 from the 5V 2.5 (or a 4A) DC wall adapter plugged into the barrel jack. Even though USB can provide power to the board, the current isn't adequate for lighting up hundreds and thousands of LEDs!

Libraries

We'll need to make sure we have these libraries installed. (Check out this link on installing libraries if needed.)

  • adafruit_bitmap_font
  • adafruit_bus_device
  • adafruit_display_text
  • adafruit_esp32spi
  • adafruit_io
  • adafruit_matrixportal
  • adafruit_requests.mpy
  • neopixel.mpy

Connect to the Internet

Once you have CircuitPython setup and libraries installed we can get your board connected to the Internet. The process for connecting can be found here.

Text Editor

Adafruit recommends using the Mu editor for editing your CircuitPython code. You can get more info in this guide.

Alternatively, you can use any text editor that saves simple text files.

Code

Copy the code from the code-block below and paste it into the Mu editor and save it to your Metro M4 Airlift as code.py (or copy code.py from the zip file and place on the CIRCUITPY drive).

# Run on Metro M4 Airlift w RGB Matrix shield and 64x32 matrix display
# show current value of Bitcoin in USD

import time
import board
import terminalio
from adafruit_matrixportal.matrixportal import MatrixPortal

# You can display in 'GBP', 'EUR' or 'USD'
CURRENCY = "USD"
# Set up where we'll be fetching data from
DATA_SOURCE = "https://api.coindesk.com/v1/bpi/currentprice.json"
DATA_LOCATION = ["bpi", CURRENCY, "rate_float"]


def text_transform(val):
    if CURRENCY == "USD":
        return "$%d" % val
    if CURRENCY == "EUR":
        return "‎€%d" % val
    if CURRENCY == "GBP":
        return "£%d" % val
    return "%d" % val


# the current working directory (where this file is)
cwd = ("/" + __file__).rsplit("/", 1)[0]

matrixportal = MatrixPortal(
    url=DATA_SOURCE,
    json_path=DATA_LOCATION,
    status_neopixel=board.NEOPIXEL,
    default_bg=cwd + "/bitcoin_background.bmp",
    debug=False,
)

matrixportal.add_text(
    text_font=terminalio.FONT,
    text_position=(27, 16),
    text_color=0x3d1f5c,
    text_transform=text_transform,
)
matrixportal.preload_font(b"$012345789")  # preload numbers
matrixportal.preload_font((0x00A3, 0x20AC))  # preload gbp/euro symbol

while True:
    try:
        value = matrixportal.fetch()
        print("Response is", value)
    except (ValueError, RuntimeError) as e:
        print("Some error occured, retrying! -", e)

    time.sleep(3 * 60)  # wait 3 minutes

Background Bitmap

From the project zip file, drag the bitcoin_background.bmp file onto the Feather's CIRCUITPY drive.

This is a 64x32 pixel .bmp file, designed for this use on this display -- you can edit it or swap in your own graphics if you like.

How it Works

First we'll import some libraries to help with the heavy lifting. The time library will allow us to pause (or sleep) for three minutes between check of the Bitcoin value index.

The board library gives us access to the Metro M4 Airlift's pin definitions.

The terminalio library will be used for the price font.

And, last but not least, adafruit_matrixportal library will handle online connectivity and json file parsing when checking the Coindesk data.

Currency and Data

The CURRENCY variable can be set to either GBP, EUR, or USD. These are the three key values supported by the Coindesk API.

Next well set the data source of the Coindesk json file as DATA_SOURCE = "https://api.coindesk.com/v1/bpi/currentprice.json"

If you go to codebeautify.org/jsonviewer and enter the above URL you'll see the json file with output like this:

The DATA_LOCATION variable provides the data key:value hierarchy we need to traverse. DATA_LOCATION = ["bpi", CURRENCY, "rate_float"] when parsed from the above json file will return the value of 11762.7728 for USD.

Text Transform

The text_transform() function will be used to turn the rate float value into a string we can display, including the currency symbol, such as $11762

Matrixportal Setup

Next, the MatrixPortal object is created with the url, json_path, status_neopixel, background bitmap file, and debug arguments set.

Text is added to the matrixportal object so it can display the Bitcoin value string using terminalio.FONT, at an x/y position of 27, 16, in a nice blue color.

The glyphs (characters) that will be used are preloaded for speed.

Main Loop

In the main loop of the program we simply run value - matrixportal.fetch(). This will grab the json file, parse it, and updated the display with the current value.

Then, we use time.sleep(3 * 60) to wait three minutes until the next check!

LED Diffusion Acrylic

You can add an LED diffusion acrylic faceplate to the your LED matrix display. (Pictured here with the ON AIR project)

This can help protect the LEDs as well as enhance the look of the sign both indoors and out by reducing glare and specular highlights of the plastic matrix grid.

Measure and Cut the Plastic

You can use the sign to measure and mark cut lines on the paper backing of the acrylic sheet.

Then, use a tablesaw or bandsaw with a fine toothed blade and a guide or sled to make the cuts.

Note: it is possible to score and snap acrylic, but it can be very tricky to get an even snap without proper clamping.

Peel away the paper backing from both sides and set the acrylic onto your matrix display.

Uglu Dashes

The best method we've found for adhering acrylic to the matrix display is to use Uglu Dashes clear adhesive rectangles from Pro Tapes. They are incredibly strong (although can be removed if necessary), easy to apply, and are invisible once attached.

Use one at each corner and one each at the halfway point of the long edges, then press the acrylic and matrix panel together for about 20 seconds.

Here you can see the impact of using the diffusion acrylic. (Pictured here with the ON AIR sign project)

Stand

A very simple and attractive way to display your matrix is with the adjustable bent-wire stand.

Alternately, you can use a frame, 3D printed brackets, tape, glue, or even large binder clips to secure the acrylic to the sign and then mount it on on a wall, shelf, or display cabinet.

These mini-magnet feet can be used to stick the sign to a ferrous surface.

This guide was first published on Aug 25, 2020. It was last updated on Aug 25, 2020.