maximal annoyance with the BBC micro:bit and MicroPython

I just picked up a micro:bit, the little educational microprocessor board originally from the BBC. It’s a nice little unit, though like all educational resources, it’s sometimes hard to access resources as a non-edu type.

I landed upon MicroPython, a Python language subset that runs directly on the micro:bit’s ARM chip. I rather like the Mu editor:
To give the old microcontroller grumps something real to complain about, MicroPython includes a bunch of very high-level functions, such as a powerful music and sound module. Getting the sound out is easy: just croc-clip a speaker onto the output pads:

(MicroPython warns against using a piezo buzzer as a speaker, but mine worked fine — loudly and supremely annoyingly — with a large piezo element. Some piezos have a fixed-frequency oscillator attached, but this simple one was great.)

This trivial example plays the Nyan Cat theme forever, but every time it loops it gets faster. The beats variable starts at the default 120 bpm, but is increased by one every time:

# nyan but it gets faster
import music
beats = 120
while True:
    beats = beats + 1

This starts out as merely irritating, but quite quickly becomes deeply annoying, and in mere hours become vastly vexing. I’m sure you’d only use this power for good …

Ⓗⓞⓦ ⓣⓞ ⓑⓔ ⓐⓝⓝⓞⓨⓘⓝⓖ ⓦⓘⓣⓗ Ⓟⓔⓡⓛ ⓐⓝⓓ Ⓤⓝⓘⓒⓞⓓⓔ

It’s been so long since I’ve programmed in Perl. Twelve years ago, it was my life, but what with the Raspberry Pi intervening, I hadn’t used it in a while. It’s been so long, in fact, that I wasn’t aware of the new language structures available since version 5.14. Perl’s Unicode support has got a lot more robust, and I’m sick of Python’s whining about codecs when processing anything other than ASCII anyway. So I thought I’d combine re-learning some modern Perl with some childish amusement.

What I came up with was a routine to convert ASCII alphanumerics ([0-9A-Za-z]) to Unicode Enclosed Alphanumerics ([⓪-⑨Ⓐ-Ⓩⓐ-ⓩ]) for advanced lulz purposes. Ⓘ ⓣⓗⓘⓝⓚ ⓘⓣ ⓦⓞⓡⓚⓢ ⓡⓐⓣⓗⓔⓡ ⓦⓔⓛⓛ:

# - ⓑⓔ ⓐⓝⓝⓞⓨⓘⓝⓖ ⓦⓘⓣⓗ ⓤⓝⓘⓒⓞⓓⓔ
# created by scruss on 2014-05-18

use v5.14;
# fun UTF8 tricks from
use strict;
use utf8;
use warnings;
use charnames qw( :full :short );
sub annoyify;

die "usage: $0 ", annoyify('string to print like this'), "\n" if ( $#ARGV < 0 );
say annoyify( join( ' ', @ARGV ) );

# 💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩

sub annoyify() {
    # convert ascii to chars in circles
    my $str = shift;
    my @out;
    foreach ( split( '', $str ) ) {
        my $c = ord($_);             # remember, can be > 127 for UTF8
        if ( $c == charnames::vianame("DIGIT ZERO") )
            # 💩💩💩 sigh; this one's real special ... 💩💩💩
            $c = charnames::vianame("CIRCLED DIGIT ZERO");
        elsif ($c >= charnames::vianame("DIGIT ONE")
            && $c <= charnames::vianame("DIGIT NINE") )
            # numerals, 1-9 only (grr)
            $c =
              charnames::vianame("CIRCLED DIGIT ONE") +
              $c -
              charnames::vianame("DIGIT ONE");
        elsif ($c >= charnames::vianame("LATIN CAPITAL LETTER A")
            && $c <= charnames::vianame("LATIN CAPITAL LETTER Z") )
            # upper case
            $c =
              charnames::vianame("CIRCLED LATIN CAPITAL LETTER A") +
              $c -
              charnames::vianame("LATIN CAPITAL LETTER A");
        elsif ($c >= charnames::vianame("LATIN SMALL LETTER A")
            && $c <= charnames::vianame("LATIN SMALL LETTER Z") )
            # lower case
            $c =
              charnames::vianame("CIRCLED LATIN SMALL LETTER A") +
              $c -
              charnames::vianame("LATIN SMALL LETTER A");
        else {
            # pass thru non-ascii chars
        push @out, chr($c);
    return join( '', @out );

Yes, I really did have to do that special case for ⓪; ⓪…⑨ are not contiguous like ASCII 0…9. ⓑⓞⓞ!

Introducing RAFTP — the Really Annoying File Transfer Protocol

I would like to describe a new and highly impractical method of transferring data between computers. Modern networks are getting more efficient every year. This protocol aims to reverse this trend, as RAFTP features:

  1. Slow file transfers
  2. A stubborn lack of error correction
  3. The ability to irritate neighbours while ensuring inaccurate transmission through playing the data over the air using Bell 202 tones.
Figure 1

Figure 1 shows a test image before it was converted into PGM format. This was then converted into an audio file using minimodem:

minimodem --tx -v 0.90 -f doge-small-1200.wav 1200 < doge-small-tx.pgm

This file was then transferred to an audio player. To ensure maximal palaver, the audio player was connected to a computer via a USB audio interface and a long, minimally-shielded audio cable. The output was captured as mp3 by Audacity as this file: RAFTP-demo

The mp3 file was then decoded back to an image:

madplay -o wav:- RAFTP-demo.mp3   | minimodem --rx -q -f - 1200 | rawtopgm 90 120 | pnmtopng > doge-small-rx.png

Figure 2 shows the received and decoded file:

Figure 2
Figure 2

Ever heard the term “Appropriate Use of Technology”?

Well, this is not that: For He’s a Jolly Good Fellow [mp3], as played on this:

— an Arduino driving a stepper motor driving a Sankyo musical box. And yes, heat-shrink tubing ‘reinforced’ with dental floss doesn’t make a very robust flexible coupling.