Standalone microbit scrolling displays

I wanted to make a scrolling display for my desk on parents’ evening, and thought I might use a micro:bit. Then I thought 5 micro:bits might be even better. But how to get them scrolling one message across? I didn’t want to use a computer to control them, I wanted them to be standalone, self-contained. And the radio abilities of the micro:bit mean that no wires should be needed.

So here’s a very simple bit of Python that will turn any number of micro:bits into a rough and ready big scrolling display. There are two different programs, one for the transmitting micro:bit which goes on the right-hand end. Code your message into the Python script and flash it using the Mu editor. When all your other micro:bits are ready, press button A to begin.

--------------------
|RX4|RX3|RX2|RX1|TX|
--------------------

The receiver code goes on all the other micro:bits numbered 1 upwards, lower numbers on the right. Change the number for each device. When powered up they stay blank until they receive the message from the transmitter.

Transmitter code – this goes on the micro:bit on the far right. Code your message in here:

from microbit import *
import radio

message = 'Mr Booth - ICT'

while True:
    if button_a.was_pressed():
        radio.on()
        radio.send(message)
        while True:
            display.scroll(message)

Here’s the receiver code – change the rxnumber for the device number, numbering from 1 on the right, higher numbers as you go left:

from microbit import *
import radio
radio.on()

# set the receive device number here
rxnumber = 1

sleeptime = rxnumber * 750

while True:
    incoming = radio.receive()
    if incoming:
        sleep(sleeptime)
        while True:
            display.scroll(incoming)

UPDATE

Unbeknown to me, Philip Meitiner of the micro:bit Educational Foundation has been working on pretty much exactly the same idea! Can’t wait to see his code as I suspect his is a much more elegant solution:

Found time to work on my #microbit RC matrix. Smooth scrolling was target for weekend – almost there! Lots of todos but a nice milestone :) pic.twitter.com/ltxOTggHgg

— Philip Meitiner (@pragmaticPhil) November 5, 2017