We Saw a Chicken …

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  • looks like your dodgy uncle

    the dried, lumpy and in places mouldy remains of a carved turnip head lantern
    time hasn’t been kind to the neep lantern‘s fizzog

  • I (U+1F494, BROKEN HEART) UTF-8

    Something has gone very wrong with the database encoding on this blog after a recent update, so all my lovely UTF-8 characters have gone mojibake.

    Trying to find ways to fix it. It may have to be manual. Remember, kids: have backups before letting WordPress upgrade!

    Here’s the Python equivalent of what I think the database has done:

    bytes("I ???? UTF-8", encoding='utf-8').decode(encoding='cp1252')
'I 💔 UTF-8'

    Quite why my hosting thought a character encoding from last century was appropriate, I’ll never know.

    Update, November 2023: kinda-sort fixed the backend, but the encoding is still weird — can we…?

  • I spent all of yesterday calculating circular key grids …

    12 green forked twig-like motifs arranged around a circle
    a green thing

    … only to realize I don’t really like circular key grids.

  • one perfect cayenne

    bright red cayenne pepper in amongst leaves on a pepper plant
    the new hotness
  • Autumn in Canada: PicoMite version

    Autumn in Canada: PicoMite version

    So I ported autumn in canada from OpenProcessing to PicoMite BASIC on the Raspberry Pi Pico:

    a small black screen images with text in the centre: autumn in canada scruss, 2021-11 just watch ...
    no leaves
    a small black screen images with text in the centre: autumn in canada scruss, 2021-11 just watch ... with one red and one orange maple leaf sitting on top of it
    a couple of leaves
    a small black screen images with text in the centre: autumn in canada scruss, 2021-11 just watch ... with four red/yellow/orange maple leaves sitting on top of it
    more leaves
    a small black screen images with text in the centre: autumn in canada scruss, 2021-11 just watch ... with sixteen simulated fallen maple leaves mostly covering it
    plenty of leaves
    a small black screen image completely covered with many simulated fallen maple leaves
    far too many leaves

    The biggest thing that tripped me up was that PicoMite BASIC starts arrays at 0. OPTION BASE 1 fixes that oversight. It would have been nice to have OpenProcessing’s HSV colour space, and an editor that could handle lines longer than 80 characters that didn’t threaten to bomb out if you hit the End key, but it’ll serve.

    Source below:

    ' autumn in canada
' scruss, 2021-11
' a take on my https://openprocessing.org/sketch/995420 for picomite

OPTION base 1
RANDOMIZE TIMER
' *** initialize polar coords of leaf polygon and colour array
DIM leaf_rad(24), leaf_ang(24), px%(24), py%(24)
FOR i=1 TO 24
    READ leaf_rad(i)
NEXT i
FOR i=1 TO 24
    READ x
    leaf_ang(i)=RAD(x)
NEXT i

DIM integer c%(8)
FOR i=1 TO 8
    READ r%, g%, b%
    c%(i)=RGB(r%,g%,b%)
NEXT i

' *** set up some limits
min_scale%=INT(MIN(MM.HRES, MM.VRES)/8)
max_scale%=INT(MIN(MM.HRES, MM.VRES)/6)
min_angle=-30
max_angle=30
min_x%=min_scale%
min_y%=min_x%
max_x%=MM.HRES - min_x%
max_y%=MM.VRES - min_y%

CLS
TEXT MM.HRES/2, INT(MM.VRES/3), "autumn in canada", "CM"
TEXT MM.HRES/2, INT(MM.VRES/2), "scruss, 2021-11", "CM"
TEXT MM.HRES/2, INT(2*MM.VRES/3), "just watch ...", "CM"

kt%=0
DO
    cx% = min_x% + INT(RND * (max_x% - min_x%))
    cy% = min_y% + INT(RND * (max_y% - min_y%))
    angle = min_angle + RND * (max_angle - min_angle)
    sc% = min_scale% + INT(RND * (max_scale% - min_scale%))
    col% = 1 + INT(RND * 7)
    leaf cx%, cy%, sc%, angle, c%(7), c%(col%)
    kt% = kt% + 1
LOOP UNTIL kt% >= 1024

END

SUB leaf x%, y%, scale%, angle, outline%, fill%
    FOR i=1 TO 24
        px%(i) = INT(x% + scale% * leaf_rad(i) * COS(RAD(angle)+leaf_ang(i)))
        py%(i) = INT(y% - scale% * leaf_rad(i) * SIN(RAD(angle)+leaf_ang(i)))
    NEXT i
    POLYGON 24, px%(), py%(), outline%, fill%
END SUB

' radii
DATA 0.536, 0.744, 0.608, 0.850, 0.719
DATA 0.836, 0.565, 0.589, 0.211, 0.660, 0.515
DATA 0.801, 0.515, 0.660, 0.211, 0.589, 0.565
DATA 0.836, 0.719, 0.850, 0.608, 0.744, 0.536, 1.000
' angles
DATA 270.000, 307.249, 312.110, 353.267, 356.540
DATA 16.530, 18.774, 33.215, 3.497, 60.659, 72.514
DATA 90.000, 107.486, 119.341, 176.503, 146.785, 161.226
DATA 163.470, 183.460, 186.733, 227.890, 232.751, 270.000, 270.000
' leaf colours
DATA 255,0,0, 255,36,0, 255,72,0, 255,109,0
DATA 255,145,0, 255,182,0, 255,218,0, 255,255,0

    You could probably use AUTOSAVE and paste the text into the PicoMite REPL. I used an ILI9341 SPI TFT LCD Touch Panel with my Raspberry Pi Pico along with some rather messy breadboard wiring.

    Fun fact: the maple leaf polygon points are derived from the official definition of the flag of Canada.

  • p-touch Pico pin labels

    breadboard with Raspberry Pi Pico attached, and two labels running down the sides with the pin names
    Pico pin labels: not bad for a first try

    This worked better than I expected. The tricky parts are trimming the edges and getting it them straight.

    Here’s the image to print on your label maker:

    combined Pico pin labels printed sideways on a tape label
    print on 12.7 mm tape
  • Raspberry Pi Zero 2 W: slides and thermals

    Raspberry Pi Zero 2 W: slides and thermals

    Slides from last night’s talk:

    Meet_the_Raspberry_Pi_Zero_2_W.odpDownload

    It’s impossible to have a Raspberry Pi Zero overheat unless you overclock it. That’s why you don’t get any cases for it with fans or heat sinks. The quad-core Raspberry Pi Zero 2 W, though, has the potential to do so. Here are some numbers:

    • Used official case with lid fitted: increases SoC temperature +3 °C over free air
    • Test – CPUBurn: https://github.com/pmylund/cpuburn
    • Tested 4, 3 and 2 cores burning in 32-bit and 64-bit modes: time from idle to throttling (80 °C) measured
    • GPU overheat not tested.
    line graph of cpu temperature against time. Temperature rises sharply from about 47 degrees C to 82 degrees C in around four minutes
    All 4 cores burning, 64-bit mode: time to overheat = under 3½ minutes
    line graph of cpu temperature against time. Temperature rises sharply from about 47 degrees C to 82 degrees C in just over four minutes
    All 4 cores burning, 32-bit mode: time to overheat = just over 4 minutes
    line graph of cpu temperature against time. Temperature rises moderately from about 47 degrees C to 81 degrees C in around seven minutes
    3 out of 4 cores burning, 64-bit mode: time to overheat = just over 7 minutes
    line graph of cpu temperature against time. Temperature rises slowly from about 47 degrees C to 81 degrees C in around ten minutes
    3 out of 4 cores burning, 32-bit mode: time to overheat = 9½ minutes
    line graph of cpu temperature against time. Temperature rises very slowly, reach 70 degrees C in 40 minutes and then only rising very slightly to about 73 degrees C in the entire run time of 3 hours 20 minutes
    2 out of 4 cores burning, 32-bit mode: time to overheat = basically never

    Unless you’re doing things that might indicate you should be using a bigger computer, a Raspberry Pi Zero 2 W won’t overheat and doesn’t need any form of cooling. If you’re overclocking, well … it’s your choice to have cooling equipment worth more than the computer it’s trying to cool.

  • Neep Lantern 2021

    carved swede/turnip with eyes cut out as crosses, two nostrils and a lopsided grin lit from inside by a small candle. (the smell is fairly atrocious, but emotive of the day)
    My neep lantern for Halloween 2021

    What you can’t see is the smell of Halloween: the hum of charred turnip from the candle inside.

  • Raspberry Pi Zero 2 W: initial performance

    Running A Pi Pie Chart turned out some useful performance numbers. It’s almost, but not quite, a Raspberry Pi 3B in a Raspberry Pi Zero form factor.

    32-bit mode

    Running stock Raspberry Pi OS with desktop, compiled with stock options:

    pie chart comparing multi-thread numeric performance of Raspberry Pi Zero 2 W: slightly faster than a Raspberry Pi 2B
    multi-thread results
    pie chart comparing single-thread numeric performance of Raspberry Pi Zero 2 W: slightly faster than a Raspberry Pi 2B
    single-thread results
    time ./pichart-openmp -t "Zero 2W, OpenMP"
pichart -- Raspberry Pi Performance OPENMP version 36

Prime Sieve          P=14630843 Workers=4 Sec=2.18676 Mops=427.266
Merge Sort           N=16777216 Workers=8 Sec=1.9341 Mops=208.186
Fourier Transform    N=4194304 Workers=8 Sec=3.10982 Mflops=148.36
Lorenz 96            N=32768 K=16384 Workers=4 Sec=4.56845 Mflops=705.102

The Zero 2W, OpenMP has Raspberry Pi ratio=8.72113
Making pie charts...done.

real	8m20.245s
user	15m27.197s
sys	0m3.752s

-----------------------------

time ./pichart-serial -t "Zero 2W, Serial"
pichart -- Raspberry Pi Performance Serial version 36

Prime Sieve          P=14630843 Workers=1 Sec=8.77047 Mops=106.531
Merge Sort           N=16777216 Workers=2 Sec=7.02049 Mops=57.354
Fourier Transform    N=4194304 Workers=2 Sec=8.58785 Mflops=53.724
Lorenz 96            N=32768 K=16384 Workers=1 Sec=17.1408 Mflops=187.927

The Zero 2W, Serial has Raspberry Pi ratio=2.48852
Making pie charts...done.

real	7m50.524s
user	7m48.854s
sys	0m1.370s

    64-bit

    Running stock/beta 64-bit Raspberry Pi OS with desktop. Curiously, these ran out of memory (at least, in oom-kill‘s opinion) with the desktop running, so I had to run from console. This also meant it was harder to capture the program run times.

    The firmware required to run in this mode should be in the official distribution by now.

    pie chart comparing 64 bit multi-thread numeric performance of Raspberry Pi Zero 2 W: slightly faster than a Raspberry Pi 2B
    multi-thread, 64 bit: no, I can’t explain why Lorenz is better than a 3B+
    pie chart comparing 64 bit single-thread numeric performance of Raspberry Pi Zero 2 W: slightly faster than a Raspberry Pi 2B
    single thread, again with the bump in Lorenz performance
    pichart -- Raspberry Pi Performance OPENMP version 36

Prime Sieve          P=14630843 Workers=4 Sec=1.78173 Mops=524.395
Merge Sort           N=16777216 Workers=8 Sec=1.83854 Mops=219.007
Fourier Transform    N=4194304 Workers=4 Sec=2.83797 Mflops=162.572
Lorenz 96            N=32768 K=16384 Workers=4 Sec=2.66808 Mflops=1207.32

The Zero2W-64bit has Raspberry Pi ratio=10.8802
Making pie charts...done.

-------------------------

pichart -- Raspberry Pi Performance Serial version 36

Prime Sieve          P=14630843 Workers=1 Sec=7.06226 Mops=132.299
Merge Sort           N=16777216 Workers=2 Sec=6.75762 Mops=59.5851
Fourier Transform    N=4194304 Workers=2 Sec=7.73993 Mflops=59.6095
Lorenz 96            N=32768 K=16384 Workers=1 Sec=9.00538 Mflops=357.7

The Zero2W-64bit has Raspberry Pi ratio=3.19724
Making pie charts...done.

    The main reason for the Raspberry Pi Zero 2 W appearing slower than the 3B and 3B+ is likely that it uses LPDDR2 memory instead of LPDDR3. 64-bit mode provides is a useful performance increase, offset by increased memory use. I found desktop apps to be almost unusably swappy in 64-bit mode, but there might be some tweaking I can do to avoid this.

    Unlike the single core Raspberry Pi Zero, the Raspberry Pi Zero 2 W can be made to go into thermal throttling if you’re really, really determined. Like “3 or more cores running flat-out“-determined. In my testing, two cores at 100% (as you might get in emulation) won’t put it into thermal throttling, even in the snug official case closed up tight. More on this later.

    (And a great big raspberry blown at Make, who leaked the Raspberry Pi Zero 2 W release a couple of days ago. Not classy.)

  • Modding an Adafruit PIR for 3.3 volts

    green circuit board covered in surface mount components. A grey wire has been soldered to the output pin of the SOT-89 package 7133-1 voltage regulator
    slightly dodgy soldering of a grey jumper wire to the Vout pin of the PIR’s voltage regulator

    Consider the Adafruit PIR (motion) sensor (aka PIR Motion Sensor, if you’re in Canada). Simple, reliable device, but only runs from a 5 V supply. Yes, there are smaller PIRs that run off 3.3 V, but if this is what you have, you need to do some soldering. Annoyingly, the sensor on the board is a 3.3 V part, but the carrier was designed in Olden Tymes when King 5 V ruled.

    You can try powering it from 3.3 V, but it’ll go all off on its own randomly as its own power supply won’t be supplying enough voltage. There are a couple of sites on how to modify these PIRs that either describe old kit you can’t get any more, or do it completely wrongly. Just one post on the Adafruit support forum gets it right.

    One way of doing this is to provide 3.3 V directly to the output pin of the voltage regulator, and ignore the 5 V power line entirely. The regulator’s a SOT89-3 part that looks a bit like this:

    71xx-1 SOT-89 package outline, with three pins at the bottom and one large ground tab (connected to centre pin, but not visible) at the top
    wee leggy thing

    In the photo above, it’s flipped over. Whichever way it’s oriented, we want to put power directly into the Vout pin. There may be easier points to solder this to than a tiny surface mount pin (almost definitely one of the capacitors) but this has held for me.

    How to use it in MicroPython? Like the TTP223 capacitive touch sensors I looked at before, a PIR gives a simple off/on output, so you can use something like this:

    from machine import Pin
from time import sleep_ms

pir = Pin(21, Pin.IN)

while True:
    print("[", pir.value(), "]")
    sleep_ms(1000)

    value() will return 1 if there’s movement, 0 if not. There are trigger time and sensitivity potentiometers to fiddle with on the board if you need to tweak the output.

    line graph showing output signal going from 0 to 1, back down to 0 and ending at one over a period of about 20 seconds
    Thonny plotter output showing a couple of movement detections. High output (on my device) stays up for about 4 seconds, so you can be pretty leisurely about polling PIRs

    Just remember: don’t connect the 5 V power line if you make this mod. I’m not responsible for any smoke emitted if you do — but I can always sell you a replacement …

  • Lentil Soup

    Ingredients

    • 6 cups vegetable stock (or 3 veggie stock cubes + 6 cups water)
    • 3-4 medium onions, chopped roughly
    • 4-6 medium carrots; half chopped roughly, half grated
    • 2 cups red split lentils
    • 4-6 tbsp olive oil
    • 2 tbsp baking soda (for soaking lentils)

    Optional ingredients

    • 1 tbsp prepared Dijon mustard
    • 1 tbsp sweet paprika

    Lentil Preparation

    • Rinse and drain lentils at least three times: they should no longer clump, and rinse water should not be very cloudy
    • Soak lentils in water with baking soda for at least an hour, occasionally stirring gently
    • Rinse lentils and soak for at least an hour in clean water; drain.

    Method

    1. Bring stock to a boil in a large pot. Add grated/chopped carrots and half the olive oil
    2. Fry onions in the rest of the olive oil until translucent, optionally with paprika
    3. Add fried onions to soup pot. Stir in Dijon mustard, if desired
    4. Cover and allow to low boil for 5-10 minutes
    5. Stir in drained lentils, and bring to a robust simmer
    6. Cover and simmer for 15 minutes.
    7. Serve and season to taste.

    Notes

    • This is based on my parents’ various lentil soup recipes from Scotland. They might use a ham or lamb-bone based stock
    • Until recently, I’d been overcooking the lentils. Red split lentils are quite delicate, and soaking and lightly simmering gives a pleasing result
    • The soaking in baking soda stage helps to de-gas the lentils

  • Another Raspberry Pi Pico language: MMBasic

    It’s very much a work in progress, but Geoff Graham and Peter Mather’s MMBasic runs nicely on the Raspberry Pi Pico. Development is mostly coordinated on TheBackShed.com forum.

    It supports an impressive range of displays and peripherals. The project gives me a very distinct “This is how we do things” vibe, and it’s quite unlike any other Raspberry Pi Pico project.

    To show you what MMBasic code looks like, here’s a little demo that uses one of those “Open Smart” LED traffic lights on physical pins 14-16 which cycles through the phases every few seconds:

    ' traffic light on gp10-12 (green, yellow, red), pins 14-16

' set up ports for output
FOR i=14 TO 16
  SETPIN i, DOUT
  PIN(i)=0
NEXT i

red=16
amber=15
green=14

DO
  ' green on for 5 seconds
  PIN(red)=0
  PIN(green)=1
  PAUSE 5000
  ' amber on for 3 seconds
  PIN(green)=0
  PIN(amber)=1
  PAUSE 3000
  ' red on for 5 seconds
  PIN(amber)=0
  PIN(red)=1
  PAUSE 5000
LOOP

  • gecko at the watering hole, forever

    a looped GIF animation of a spotted sand/brown coloured gecko calmly drinking from a water bowl using its broad pink tongue
    Source: invertebrate on Twitter: “at the watering hole https://t.co/K6jWSQTYf0” / Twitter
    • Video downloaded using youtube-dl
    • Resized to 360p and 30 fps using ffmpeg
    • Loop found and resized using MoviePy, with ffmpeg used to create the gif
    • gif optimized using gifsicle -O3

    Result: 320×180, 22 frames, 128 colours, ~ 600 KB.

  • Some okay CMYK results from DrawingBot, finally …

    decorative 8-sided symmetrical square tile sketched out in cyan, magenta, yellow and grey felt tip pen on a plotter
    drawn using a Roland DXY-1300 plotter on Strathmore Multimedia using DeSerres medium tip pens, ~60 minutes plotting time, 180 × 180 mm

    After a tonne of faffing about, I finally got something out of my plotter using Drawing Bot. I’d heard about it during the Bold Machines’ Intro to Pen Plotters course I’m taking, and the results that other people were getting looked encouraging. But for me, they weren’t great.

    Maybe I was choosing too large images, but my main problem was ending up with plots with far too many lines: these would take days to plot. The controls on Drawing Bot also seemed limited: density and resolution seemed to be the only controls that do much. Drawing Bot itself wasn’t very reliable: it would sometimes go into “use all the cores!” mode when it was supposed to be idling. It would also sometimes zoom in on part of the image and fail to unzoom without quitting. Is a 32 GB i7 8-core (oldish, but still game) too little for this software? Forget any of the Voronoi plots if you want to see results today.

    The source image was a geometric tile that I’d frisketed out years ago, forgotten about, and then found when I unstuck it from under a stack of papers. It’s somewhat artisanally coloured by me in watercolour, and the mistakes and huge water drop are all part of its charm:

    geometric tile picked out in brown, red, pink, green and various shades of faded blue, separated by rough white frisket lines
    source image for plotter output

    If WordPress will allow an SVG, here’s what Drawing Bot made of it:

    scribbly linedrawing of the tile image in CMYK process colours
    Drawing Bot SVG output: yes, it’s that faint

    I do like the way that Drawing Bot seems to have ignored some colours, like the rose pink around the outside. The green border really is mostly cyan with a touch of black.

    I haven’t magically found perfect CMYK pens in HP/Roland pen format. I couldn’t even find the Schwan-Stabilo Point 88 pens that Lauren Gardner at Bold Machines recommends. But the local DeSerres did deliver a selection of their own-brand 1.0mm Mateo Markers that are physically close to the Point 88s in size, but use a wider 1 mm fibre tip. They are also cheap; did I mention that?

    The colours I chose were:

    • for cyan: Mint Green; RGB colour: #52C3A5; SKU: DFM-53
    • for magenta: Neon Pink; RGB colour: #FF26AB; SKU: DFM-F23
    • for yellow: Neon Yellow; RGB colour: #F3DE00; SKU: DFM-F01
    • for black: Green Grey 5; RGB colour: #849294; SKU: DFM-80

    The RGB colours are from DeSerres’ website, and show that I’m not wildly off. Target process colours are the top row versus nominal pen colours on the bottom:

    target vs pen CMYK colours
    yes, there are fluo colours in there

    I knew to avoid pure black, as it would overpower everything in the plot.

    To make the pens work with the DXY-1300, I modified juliendorra/3D-printable-plotter-adapters-for-pens-and-refills: Use your favorite pens with vintage HP plotters: parametric code to create custom adapters to work the the DeSerres pens. Here are my changed files, just in case my PR isn’t accepted:

    DeSerresMateoPlotterPenAdapter.zipDownload

    Overall, it plotted quite well. I plotted directly from Inkscape, one layer/pen at a time, from light (yellow) to dark (grey). Using the pen 1 slot had its disadvantages: the DXY has little pen boots to stop the pens drying, but these unfortunately get filled with old ink. The scribbly dark markings in the NNE and SSW orange kites in the plot are from the yellow pen picking up old black ink from the pen boot. Next time I’ll clean the plotter better.

  • Snowy, after Paul Carter

    a line drawing of a white cat walking to the left with tail raised. A bright magenta square has been applied near front shoulder
    non-artist’s impression of Snowy
    (source SVG: white cat walking by papapishu on OpenClipArt)

    I’m remembering the time that Paul coloured a perfect square with a highlighter on their white family cat, Snowy. She had a pink side for weeks.

  • for Paul Carter, after 15 years

    All the Colours We Have (for Paul Carter) — 2021 re-encoding

    It’s hard to believe that Paul Carter has been gone fifteen years. Like all things digital, my ten year memorial for him was a bit dusty, so I did a re-encoding that will look better on today’s devices. The info page is unchanged.

    Still miss you, buddy. It gets further but no easier.

  • Tetris for Applesoft BASIC

    a tetris game tableau, paused, with a completed line of bricks about to be removed
    a very paused game

    Paleotronic’s Tetris for Applesoft BASIC is a surprisingly decent version for something that’s written in an interpreted language. It’s not what anyone would call zippy, but it’s not so slow that you want to give up.

    Paleotronic want you to type it in, but life’s too short for that. You can play it in your browser on the Internet Archive: Tetris for Applesoft BASIC by Mark Stock

    Or download an auto-booting Apple II disk image:

    AppleSoftTetris.zipDownload

    Keys:

    • , — move left
    • . — move right
    • A — rotate left
    • R — rotate right
    • Z — drop
    • P — pause
    • Q — quit

    Life’s also too short for correcting OCR errors in BASIC code. Tesseract is hilariously bad at recognizing source code, so I had to go through this several times. AppleCommander’s BASIC Tools was very handy for catching the last of the errors with its variable dump: caught the cases of the TO keyword converted to the variable T0 … and frankly, I am no fan of SmartQuotes when applied to source code, either.

    Here’s the source, straight from the interpreter with all its weird spacing:

    10  GOSUB 1000
100 W = W +1: IF W >LV  THEN W = 0: GOSUB 350
110 K =  PEEK(KB): IF K > = H  THEN  POKE KC,H:K = K -H: GOSUB 300
190  GOTO 100
200 PY = PY *A2: VLIN PY,PY +A1 AT PX: RETURN 
225 PY = PY *A2: HLIN X1,X2 AT PY: HLIN X1,X2 AT PY +A1: RETURN 
300  ON E(K) GOTO 30000,330,340,350,360,30100
310  RETURN 
330 X = X -1: GOTO 400
340 X = X +1: GOTO 400
350 DN = 1:Y = Y +1: GOSUB 400:DN = 0: RETURN 
360 S = S +1: IF S/4 =  INT(S/4)  THEN S = S -4
400  GOSUB 500
410  GOSUB 800: IF F = 0  THEN X = XX:Y = YY:S = SS: GOSUB 420: IF DN  THEN  GOSUB 900
420  COLOR= CF: FOR PP = 1 TO 4:PX = X +X(S,PP):PY = Y +Y(S,PP): GOSUB 200: NEXT PP:XX = X:YY = Y:SS = S:D = 0: RETURN 
500  IF DD  THEN  RETURN 
510  COLOR= CB: FOR PP = 1 TO 4:PX = XX +X(SS,PP):PY = YY +Y(SS,PP): GOSUB 200: NEXT PP:DD = 0: RETURN 
800 F = 1: FOR PP = 1 TO 4:PY = Y +Y(SS,PP): ON ( FN PC(X +X(S,PP)) >0) GOTO 805: NEXT PP: RETURN 
805 F = 0: RETURN 
850 F = 1: RETURN 
900 P = 10: GOSUB 30300
905 RN = 0:Y = YM
910 X = XL
920 PY = Y: IF  FN PC(X) = CB  THEN 950
930 X = X +1: IF X < = XR  THEN 920
940 R(RN) = Y:RN = RN +1
950 Y = Y -1: IF Y > = 0  THEN 910
960  IF RN  THEN  GOSUB 30400
970 Y = 0
980 X =  INT((XR -XL)/2) +XL
985 S =  INT( RND(1) *NS):CF = C(S):S = S *4
990  GOSUB 800: IF F  THEN  RETURN 
995  GOTO 31000
1000  DIM E(127),X(27,4),Y(27,4),R(40)
1010  TEXT : HOME : GR 
1011  PRINT "WELCOME..."
1014 LM = 10
1015 XM = 10:YM = 15
1016 XL =  INT((40 -XM)/2)
1017 XR = XL +XM -1
1021 A1 = 1
1022 A2 = 2
1030  DEF  FN PC(X) =  SCRN( X,PY *A2)
1040 CB = 0
1050 XX = 20:YY = 0:SS = 0
1100 KB =  -16384
1110 KC =  -16368
1120 H = 128
1129  REM KEYBOARD ACTIONS
1130  REM QUIT
1131 E( ASC("Q")) = 1
1132 E( ASC("Q") -64) = 1
1140  REM MOVE LEFT
1141 E(8) = 2
1142 E( ASC(",")) = 2
1150  REM MOVE RIGHT
1151 E(21) = 3
1152 E( ASC(".")) = 3
1160  REM MOVE DOWN
1161 E(32) = 4
1162 E( ASC("Z")) = 4
1170  REM ROTATE
1171 E( ASC("R")) = 5
1172 E(13) = 5
1173 E( ASC("A")) = 5
1179  REM PAUSE GAME
1180 E( ASC("P")) = 6
1181 E( ASC("P") -64) = 6
1185  GOSUB 2000
1186  GOSUB 1300
1190  PRINT "PRESS ANY KEY TO START..."
1191  PRINT 
1192  PRINT "PRESS Q TO QUIT."
1193  GOTO 31020
1299  REM DRAW THE GAME
1300  COLOR= 4: FOR I = 0 TO 19:X1 = 0:X2 = 39:PY = I: GOSUB 225: NEXT 
1320  COLOR= CB: FOR I = 0 TO YM:X1 = XL:X2 = XR:PY = I: GOSUB 225: NEXT 
1350  RETURN 
1400  DATA 1
1401  DATA 0,0,1,0,0,1,1,1
1402  DATA 0,0,1,0,0,1,1,1
1403  DATA 0,0,1,0,0,1,1,1
1404  DATA 0,0,1,0,0,1,1,1
1410  DATA 2
1411  DATA 0,1,1,1,2,1,3,1
1412  DATA 1,0,1,1,1,2,1,3
1413  DATA 0,1,1,1,2,1,3,1
1414  DATA 1,0,1,1,1,2,1,3
1420  DATA 12
1421  DATA 1,1,0,1,1,0,2,1
1422  DATA 1,1,0,1,1,0,1,2
1423  DATA 1,1,0,1,2,1,1,2
1424  DATA 1,1,1,0,2,1,1,2
1430  DATA 13
1431  DATA 1,1,0,1,2,1,0,2
1432  DATA 1,1,1,0,1,2,2,2
1433  DATA 1,1,0,1,2,1,2,0
1434  DATA 1,1,1,0,1,2,0,0
1440  DATA 9
1441  DATA 1,1,0,1,2,1,2,2
1442  DATA 1,1,1,0,1,2,2,0
1443  DATA 1,1,0,1,2,1,0,0
1444  DATA 1,1,1,0,1,2,0,2
1450  DATA 3
1451  DATA 1,1,1,0,0,0,2,1
1452  DATA 1,1,1,0,0,1,0,2
1453  DATA 1,1,1,0,0,0,2,1
1454  DATA 1,1,1,0,0,1,0,2
1460  DATA 6
1461  DATA 1,1,0,1,1,0,2,0
1462  DATA 1,1,0,1,0,0,1,2
1463  DATA 1,1,0,1,1,0,2,0
1464  DATA 1,1,0,1,0,0,1,2
1990  DATA  -1
2000 X = 0:Y = 0
2010 NS = 0
2020  READ C: IF C < > -1  THEN C(NS) = C: FOR J = 0 TO 3: FOR I = 1 TO 4: READ X(NS *4 +J,I): READ Y(NS *4 +J,I): NEXT I: NEXT J:NS = NS +1: GOTO 2020
2030  RETURN 
21210 P = 1: RETURN 
30000  TEXT : HOME : END 
30100  HOME 
30110  PRINT "GAME PAUSED. PRESS P TO CONTINUE..."
30120 P = 1
30130 K =  PEEK(KB): IF K > = H  THEN  POKE KC,H:K = K -H: GOSUB 30200
30140  IF P  THEN 30130
30150  HOME 
30160  PRINT "SCORE ";SC; TAB( 21);"LEVEL ";LM -LV +1
30170  RETURN 
30200  ON E(K) GOTO 30000,30210,30210,30210,30210,30220
30210  RETURN 
30220 P = 0
30230  RETURN 
30300 SC = SC +P
30310  VTAB 21: HTAB 7
30320  PRINT SC;
30330  RETURN 
30400 RN = RN -1
30410  FOR C = 0 TO 32
30415  COLOR= C
30420  FOR I = 0 TO RN:X1 = XL:X2 = XR:PY = R(I): GOSUB 225: NEXT I
30430  FOR I = 0 TO 2: NEXT I
30440  NEXT C
30450  FOR I = 0 TO RN
30460 Y = R(I) +I
30470 YP = Y -1: FOR X = XL TO XR:PY = YP: COLOR=  FN PC(X):PX = X:PY = Y: GOSUB 200: NEXT X:Y = Y -1: IF Y >0  THEN 30470
30480 P = 100: GOSUB 30300
30490  NEXT I
30495  RETURN 
31000  VTAB 22: PRINT 
31010  PRINT "              GAME OVER"
31020 P = 1
31030 K =  PEEK(KB): IF K > = H  THEN  POKE KC,H:K = K -H: GOSUB 31200
31040  IF P  THEN 31030
31050 D = 1
31060 SC = 0:LV = LM
31070  GOSUB 30150
31080  GOSUB 1300
31090  GOTO 905
31200  ON E(K) GOTO 30000
31210 P = 0: RETURN 
32000  REM END OF LISTING

    If only AppleSoft had a RENUM command, the code might not look so messy

  • Raspberry Pi Meetup: Touch Sensors

    my slides:

    TouchSensors-RaspberryPi-20210715.odpDownload
    TouchSensors-RaspberryPi-20210715.pdfDownload

  • digging the BlueSCSI

    I like old (as in 68K old) Apple Macintoshes, but I don’t like their hard drives. Apple used SCSI drives, which were super-cool at the time (multiple drives on one bus! extra devices like SCSI scanners, too!) but now seem an absolute pain. There may be a lot to complain about with USB storage, but compared to SCSI, it just works.

    While the 40 MB Quantum SCSI drive in my Mac Classic II still works, it gets really full really fast and that old spinning rust won’t spin forever. One of the newer ways to replace a SCSI drive is the BlueSCSI, an open-everything design based on a cheap Blue Pill micro-controller board, a Micro-SD card slot and some passive components. The whole kit is very affordable, and a local maker sells them, so it was worth a try.

    I’ve had nothing but miserable failure with Blue Pill boards, and very quickly moved on to STM32F4 board that actually work. It didn’t fill me with much hope that the board I got with my kit looked like this, end on:

    end-on view of a blue micro controller PCB which has - mystifyingly - two micro-USB connectors, one on either face of the PCB
    There are two USB connectors on this board.
    There are two of ____.

    Despite that oddness, it all soldered up fine (the surface-mount card slot was a little fiddly) and it fits inside the Classic II’s cavernously empty shell wherever I choose to stick it down.

    I thought I knew what I was doing in making filesystem images (hence my recent nonsense anent HFS utilities), but clearly I was wrong. The 2 GB images I made in Basilisk II weren’t recognized at all. For now, I’m booting from one of the RaSCSI canned boot images plus a couple of the blank formatted drive images to put my own custom system on.

    I’m trying to get as much as possible set up on the Micro-SD card while I can still access it, as the Classic II’s case is not something you can pop open on a whim. It needs a special long-thin Torx T15 driver to even get the case partially open, then you have to ease/fight the case the rest of the way. Aside from the faint ponk of dodgy analogue board caps (I’ll fix ’em one day, I promise!), you have to remember to tiptoe around the life-ending voltages lurking at the back of the CRT when you’re working there. Retrotechnology: it smells bad and it can kill you!

    A feature I really appreciate with the BlueSCSI is that it dumps a status log on the card every time it boots. It took me a while to get the hang of naming images correctly, but I’d have been absolutely lost without logs with this level of detail:

    BlueSCSI <-> SD - https://github.com/erichelgeson/BlueSCSI
 VERSION: 1.0-20210410
 DEBUG:0 SCSI_SELECT:0 SDFAT_FILE_TYPE:3
 SdFat version: 2.0.6
 SdFat Max FileName Length: 32
 Initialized SD Card - lets go!
 Not an image: LOG.txt
 Imagefile: HD10_512 753.hda / 41943040bytes / 40960KiB / 40MiB
 Imagefile: HD20_512 BS.hda / 41943040bytes / 40960KiB / 40MiB
 Imagefile: HD40 MacHD-1000MB.hda / 1048576000bytes / 1024000KiB / 1000MiB
 Imagefile: HD30_512 MacHD-500MB.hda / 524288000bytes / 512000KiB / 500MiB
 ID:LUN0:LUN1:
  0:----:----:
  1: 512:----:
  2: 512:----:
  3: 512:----:
  4: 512:----:
  5:----:----:
  6:----:----:
 Finished initialization of SCSI Devices - Entering main loop.

    So I’ve got four SCSI drives pretending to live on this card, and even if one of them’s not quite named correctly (HD40 MacHD-1000MB.hda should be called HD40_512 MacHD-1000MB.hda), it’s been found okay.