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.
This is a tiny detail from an unfeasibly large random walk made in Berkeley Logo. The code looks something like this:
; random dice walk, with colours for each of six directions
; scruss, 2021-07
make "ch {14 6 2 3 13 4}
make "dirs {0 60 120 180 240 300}
make "sides {1 2 3 4 5 6}
to walk
make "throw pick sides
setheading item :throw dirs
setpencolor item :throw ch
forward 20
end
hideturtle repeat 1000 [walk]
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:
Keys:
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
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:
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.
I got a Cambridge Computer Z88 again, after perhaps 30 years of not having one. They are very nice little portable computers, remarkable for packing a multi-tasking OS into an 8-bit machine that runs for weeks on 4x AA batteries.
But the Z88 is a Clive Sinclair joint, so there’s going to be at least one deeply weird and/or ill-advised detail about it. For me, it’s the power adapter. The original had a 6 V centre-positive barrel connector, but in true Sinclair fashion, that wasn’t quite ideal.
The DC power comes through a diode, which drops it down to ~5.2 V. The batteries supply up to 6 V and there’s no protection circuit, so the DC adapter won’t do anything until the internal batteries discharge down to that level. This is far from ideal.
The clever way of dealing with this was Rakewell’s Z88 PSU. This was a variable voltage PSU set to deliver 7 V, so that even when dropped through the power diode, it wouldn’t deplete the batteries.
Unfortunately, Rakewell stopped selling these a while ago. But I remembered I had a some MT3608 (datasheet) boards bought at a hamfest some years back. MT3608s are boost DC-DC converters, so they’ll convert from a lower DC voltage to a higher one, typically at least +2 V higher than the input. With a hacked-up USB cable, a small length of DC cable with a connector and a 3d printed case, I built one that works quite well, at least in the short time I’ve tested it.
So I’m refurbishing the Mac Classic II I got in 2016 now that I’ve found that BlueSCSI is a fairly cheap way of providing large replacement storage. The 40 MB (yes, 40 MB) drive from 1992 can finally be replaced.
Hit a snag, though: DiskCopy won’t copy a disk with errors, which this drive seemed to have. DiskCopy also won’t repair the boot disk, so you have to find a bootable floppy or some other way to work around this limitation. The only readily available bootable disk image I could find was the System 7.1 Disk Tools floppy — which reported no errors on my drive! Later versions of Disk First Aid would fix it, but weren’t provided on a bootable image.
Here’s the 7.1 Disk Tools floppy with all of the apps replaced by Disk First Aid 7.2. Both of these were found on the Internet Archive’s download.info.apple.com mirror and combined:
Disk duly repaired, DiskCopy was happy, backup complete. Eventually: the Classic II is not a fast machine at all.
I love the old Mac icons, how they packed so much into so few pixels:
It’s a stylized ambulance with flashing light and driver, the side is a floppy disk, it’s got motion lines and the whole icon is slanted to indicate speed/rush. Nice!
Vaguely related: most old Mac software is stored as Stuffit! archives. These don’t really work too well on other systems, as they use a compression scheme all their own and are specialized to handle the forked filesystem that old Macs use. Most emulators won’t know what to do with them unless you jump through hoops in the transfer stage.
Fortunately, the ancient Linux package hfsutils knows the ways of these hoops, if only you tell it when to jump. The script below takes a Stuffit! file as its sole argument, and creates a slightly larger HFS image containing the archive, with all the attributes set for Stuffit! Expander or what-have-you to unpack it.
#!/bin/bash
# sitdsk - make an HFS image containing a properly typed sit file
# requires hfsutils
# scruss, 2021-07
if
[ $# -ne 1 ]
then
echo Usage: $0 file.sit
exit 1
fi
base="${1%.sit}"
# hformat won't touch anything smaller than 800 KB,
# so min image size will be 800 * 1.25 = 1000 KB
size=$(du -k "$1" | awk '{print ($1 >= 800)?$1:800}')
dsk="${base}.dsk"
dd status=none of="$dsk" if=/dev/zero bs=1K count=$((size * 125 / 100))
hformat -l "$base" "$dsk"
# note that hformat does an implicit 'hmount'
hcopy "$1" ':'
# and hcopy silently changes underscores to spaces
hattrib -t 'SIT!' -c 'SITx' ":$(echo ${1} | tr '_' ' ')"
hls -l
humount
What this does:
Notice I said it “attempts” to set the file type. hfsutils does some file renaming on the fly, and all I know about is that it changes underscores to spaces. So if there are other changes made by hfsutils, this step may fail. The package also gets really confused by images smaller than 800 KB, so small archives are rounded up in size to keep hformat happy.
Everything looks like buds when you have a bud vase.
I got one of these CardKB Mini Keyboards to see if I could use it for small interactives with MicroPython devices. It’s very small, and objectively not great as a mass data entry tool. “Better than a Pocket C.H.I.P. keyboard” is how I’d describe the feel. It’s also pretty reliable.
It’s got an I²C Grove connector, and its brains are an ATMega chip just like an Arduino. It’s strictly an ASCII keyboard: that is, it sends the 8-bit ASCII code of the key combination you pressed. It doesn’t send scan codes like a PC keyboard. The driver source is in the CardKB m5-docs, so if you really felt ambitious you could write a scan code-like firmware for yourself.
The device appears at I²C peripheral address 95, and returns a single byte when polled. That byte’s either 0 if no key was pressed, or the character code of what was pressed. The Esc key returns chr(27), and Enter returns CR. If you poll the keyboard too fast it seems to lose the plot a little, so a tiny delay seems to help
Here’s a small demo for MicroPython that acts as the world’s worst typewriter:
# M5Stack CardKB tiny keyboard - scruss, 2021-06
# MicroPython - Raspberry Pi Pico
from machine import Pin, I2C
from time import sleep_ms
i2c = I2C(1, scl=Pin(7), sda=Pin(6))
cardkb = i2c.scan()[0] # should return 95
if cardkb != 95:
print("!!! Check I2C config: " + str(i2c))
print("!!! CardKB not found. I2C device", cardkb,
"found instead.")
exit(1)
ESC = chr(27)
NUL = '\x00'
CR = "\r"
LF = "\n"
c = ''
print("*** APPALLING TYPEWRITER ***")
print("** Type stuff, Esc to end **")
while (c != ESC):
# returns NUL char if no character read
c = i2c.readfrom(cardkb, 1).decode()
if c == CR:
# convert CR return key to LF
c = LF
if c != NUL or c != ESC:
print(c, end='')
sleep_ms(5)
And here’s the CircuitPython version. It has annoying tiny differences. It won’t let me use the I²C Grove connector on the Wio Terminal for some reason, but it does work much the same:
# M5Stack CardKB tiny keyboard - scruss, 2021-06
# CircuitPython - SeeedStudio Wio Terminal
# NB: can't use Grove connector under CPY because CPY
import time
import board
import busio
i2c = busio.I2C(board.SCL, board.SDA)
while not i2c.try_lock():
pass
cardkb = i2c.scan()[0] # should return 95
if cardkb != 95:
print("!!! Check I2C config: " + str(i2c))
print("!!! CardKB not found. I2C device", cardkb,
"found instead.")
exit(1)
ESC = chr(27)
NUL = '\x00'
CR = "\r"
LF = "\n"
c = ''
b = bytearray(1)
# can't really clear screen, so this will do
for i in range(12):
print()
print("*** APPALLING TYPEWRITER ***")
print("** Type stuff, Esc to end **")
for i in range(8):
print()
while (c != ESC):
# returns NUL char if no character read
i2c.readfrom_into(cardkb, b)
c = b.decode()
if c == CR:
# convert CR return key to LF
c = LF
if c != NUL or c != ESC:
print(c, end='')
time.sleep(0.005)
# be nice, clean up
i2c.unlock()
Direct download: 01-pink_noise.mp3
There are a million variations on the simple “use sox to play masking pink noise“, such as:
play -n synth pinknoise gain -3
This will play synthesized pink noise until you hit Ctrl-C.
But it you want two independent noise channels rather than mono, that’s a little more complex. It’s probably easier to download/play the MP3 file above than show you the command line.
Note that MP3s really aren’t designed to encode such random data, and it’s likely that your player will cause the audio to clip in a couple of places. I’m not quite sure why it does this, but it does it repeatably.
If you want to create this for yourself (and create a bonus lossless FLAC, which was far too large to upload here), here’s what I did to make this:
#!/bin/bash
duration='60:00'
fade='1'
outfile='pinknoise.wav'
# make the track
sox --combine merge "|sox --norm=-3 -c 1 -b 16 -r 44100 -n -p synth $duration pinknoise" "|sox --norm=-3 -c 1 -b 16 -r 44100 -n -p synth $duration pinknoise" -c 2 -b 16 -r 44100 $outfile fade $fade fade 0 $duration $fade gain -n -3
# make the cover
# 1 - text - 500 x 500 px
pnmcat -white -tb <(pbmmake -white 500 114) <(pbmtextps -font HelveticaBold -fontsize 64 -resolution 180 "PINK" | pnmcrop) <(pbmmake -white 32 32) <(pbmtextps -font HelveticaBold -fontsize 64 -resolution 180 "NOISE" | pnmcrop) <(pbmmake -white 500 114) > cover-text.pbm
# 2 - make the noise bg
pgmnoise 500 500 > cover-noise.pgm
# 3 - make the magenta text
ppmchange black magenta cover-text.pbm > cover-text-magenta.ppm
# 4 - overlay with transparency
pnmcomp -alpha=<(pnminvert cover-text.pbm | pbmtopgm 35 35 ) cover-text-magenta.ppm cover-noise.pgm | cjpeg -qual 50 -opt -baseline -dct float > cover.jpg
# delete the temporary image files, leaving cover.jpg
rm -f cover-text.pbm cover-noise.pgm cover-text-magenta.ppm
# make the mp3
lame -V 2 --noreplaygain -m s --tt 'Pink Noise' --ta 'Pink Noise' --tl 'Pink Noise' --ty $(date +%Y) --tc "scruss, 2021-05" --tn 1/1 --tg Ambient --ti cover.jpg "$outfile" 01-pink_noise.mp3
# make the flac (and delete wav file)
flac --best --output-name=01-pink_noise.flac --delete-input-file --picture=cover.jpg --tag="TITLE=Pink Noise" --tag="ARTIST=Pink Noise" --tag="ALBUM=Pink Noise" --tag="DATE=$(date +%Y)" --tag="COMMENT=scruss, 2021-05" --tag="GENRE=Ambient" --tag="TRACKNUMBER=1" --tag="TRACKTOTAL=1" "$outfile"
You’ll likely need these packages installed:
sudo apt install sox libsox-fmt-all ghostscript gsfonts-x11 netpbm lame flac libjpeg-progs
It’s only a serial SPI interface, but you can’t beat the price. It should only be used with 3.3 V micro-controllers like the Raspberry Pi Pico, since micro-SD cards don’t like 5 V directly at all.
You might want to pre-tin the pins and apply some extra flux on both surfaces, because these pads are thin and you don’t want to melt them. I used my standard SnAgCu lead-free solder without trouble, though.
You only need to use one of the Ground connections for the card to work.
If you need to ship things, you’re probably not too keen on queuing at the post office right now. Canada Post’s Ship Online service is pretty handy if you have a printer. The PDFs it produces are okay to print on plain paper, but if you’re using full-sheet labels like Avery 5165 you’re going to waste half a sheet of expensive labels.
If you’ve got two parcels to mail, this shell script will extract the right side of each page and create a single 2-up PDF with both your labels on the same page. You will need:
On my Ubuntu system, you can get good-enough¹ versions by doing this:
sudo apt install poppler-utils netpbm img2pdf
The code:
#!/bin/bash
# cp2up.sh - fits the important part of Canada Post print labels 2 per sheet
# scruss, 2021-05 - CC-BY-SA
# hard-coded input name (document.pdf)
# hard-coded output name (labels-2up.pdf)
# accepts exactly two labels (sorry)
dpi=600
width_in=11
height_in=8.5
# png intermediate format uses pixels per metre
dpm=$(echo "scale=3; $dpi * 1000 / 25.4" | bc)
# calculated pixel sizes, truncated to integer
half_width_px=$(echo "$width_in * $dpi / 2" | bc | sed 's/\..*$//')
height_px=$(echo "$height_in * $dpi" | bc | sed 's/\..*$//')
pdftoppm -mono -r "$dpi" -x "$half_width_px" -y 0 \
-W "$half_width_px" -H "$height_px" document.pdf labels
pnmcat -lr labels-1.pbm labels-2.pbm |\
pnmtopng -compression 9 -phys "$dpm" "$dpm" 1 > labels.png \
&& rm labels-1.pbm labels-2.pbm
# fix PDF time stamps
now=$(date --utc --iso-8601=seconds)
img2pdf -o labels-2up.pdf --creationdate "$now" --moddate "$now" \
--pagesize "Letter^T" labels.png \
&& rm labels.png
# saved from:
# history | tail | awk '{$1=""; print}' |\
# perl -pwle 'chomp;s/^\s+//;' > cp2up.sh
It’s got a few hard-coded assumptions:
Clever people could write code to work around these. Really clever people could modify this to feed a dedicated label printer.
Yes, I could probably have done all this with one ImageMagick command. When ImageMagick’s command line syntax begins to make sense, however, it’s probably time to retire to that remote mountain cabin and write that million-word thesis on a manual typewriter. Also, ImageMagick’s PDF generation is best described as pish.
One of the issues that this script avoids is aliasing in the bar-codes. For reasons known only to the anonymous PDF rendering library used by Canada Post, their shipping bar-codes are stored as smallish (780 × 54 px) bitmaps that are scaled up to a 59 × 19 mm print size. Most PDF viewers (and Adobe Viewer is one of these) will anti-alias scaled images, making them slightly soft. If you’re really unlucky, your printer driver will output these as fuzzy lines that no bar-code scanner could ever read. Rendering them to high resolution mono images may still render the edges a little roughly, but they’ll be crisply rough, and scanners don’t seem to mind that.
¹: Debian/Ubuntu’s netpbm package is roughly 20 years out of date for reasons that only a very few nerds care about, and the much better package is blocked by Debian’s baroque and gatekeepery packaging protocol. I usually build it from source for those times I need the new features.
A friend introduced me to A(x56) – URL Lengthener — perhaps better known as https://aaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.com/. Consequently, this website should in future be referred to as https://aaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.com/a?áaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂåAæãæãæaæââÃáÆáÆæâåâæáæäæâæâáÅåâåÆåÄáÆåáåÃåÆåæáÆ.
It sounds even better than it reads:
Sometimes, one must obey the inscrutable exhortations of one’s soul and travel deep into the inexplicable. The planet Why? has been left far behind, the chatter of its querulous denizens nothing more than a faint wisp of static. Where I’m going, pure patternlessness is all there is.
In 1955, military-industrial complex stalwarts RAND Corporation published a huge book of just pages and pages of … digits. The digits were deliberately as random as possible, and were intended to help the fledgling practice of data science carry out truly random simulations. The book was called “A Million Random Digits with 100,000 Normal Deviates”. It was also made available on punched cards, with 50 digits to a card adding up to ten boxes of 2000 cards. A single box of punched cards was about 370 × 200 × 95 mm and weighed roughly 5 kg, so these digits had heft.
I thought it might be fun (or perhaps fun?: pronounced with a rising, questioning tone to stress the might-ness of any enjoyment arising) to dig into how RAND carried out this work, create some electronics to produce a similar random stream, and see how my random digits compare for randomness with RAND’s. For a final trick, I might even typeset the whole giant table into a book that no-one wants.
As I research and progress with this project, I’ll add in links here
I must stress: there is no reason for me to do this. A $5 micro-controller board can generate tens to hundreds of thousands of truly random digits per second. Any results I produce will have no use beyond my own amusement.
A Million Random Digits with 100,000 Normal Deviates is © Copyright 2001 RAND. Apart from a couple of page images and quotations from supporting material, none of that work is reproduced here. RAND does not support or endorse my futile efforts in any way.
I’d previously mentioned RANDU — IBM’s standard scientific PRNG in the 1970s that was somewhat lacking, to say the least — some time ago, but I found a new wrinkle.
For their 1130 small computer system, IBM published the Scientific Subroutine Package [PDF], which included a cut-down version of RANDU for this 16-bit machine. The code, on page 64 of the manual, doesn’t inspire confidence:
c RANDU - from IBM Scientific Subroutine
c Package Programmer's Manual
c 1130-CM-02X - 5th ed, June 1970
c http://media.ibm1130.org/1130-106-ocr.pdf
SUBROUTINE RANDU(IX, IY, YFL)
IY = IX * 899
IF (IY) 5, 6, 6
5 IY = IY + 32767 + 1
6 YFL = IY
YFL = YFL / 32727.
RETURN
END
(If you’re not hip to ye olde Fortran lingo, that bizarre-looking IF statement means IF (IY < 0) GO TO 5; IF (IY == 0) GO TO 6; IF (IY > 0) GO TO 6)
It accepts an odd number < 32768 as a seed, and always outputs an odd number. Yes, it basically multiplies by 899, and changes the sign if it rolls over. Umm …
There are two possible orbits for this PRNG, each 8192 entries long:
The plot above is the first series as X and the second as Y. I used INTEGER*2 types to simulate the 1130’s narrow integers.
Almost no-one will need this knowledge, but I might need to remember it. In order to add Mini PPISD support to a RomWBW 3.01-supported system, you need to create a file called something like Source/HBIOS/Config/ZETA2_ppisd.asm (for yes, I’m using a Zeta SBC V2) containing:
#include "cfg_zeta2.asm" UARTCFG .SET UARTCFG | SER_RTS CRTACT .SET TRUE PPIDEENABLE .SET FALSE SDENABLE .SET TRUE PPPENABLE .SET FALSE PPISD .EQU TRUE
Running make from the top-level directory should create a ROM image called Binary/ZETA2_ppisd.rom for you to write to flash. Since my floppy drive isn’t feeling too happy, I had to resort to buying a TL866II Plus programmer to write the chip.
And it worked!
RomWBW HBIOS v3.0.1, 2021-03-12 ZETA V2 Z80 @ 8.000MHz 0 MEM W/S, 1 I/O W/S, INT MODE 2 512KB ROM, 512KB RAM CTC: MODE=Z2 IO=0x20 UART0: IO=0x68 16550A MODE=38400,8,N,1 DSRTC: MODE=STD IO=0x70 Sun 2021-03-14 17:47:13 CHARGE=OFF MD: UNITS=2 ROMDISK=384KB RAMDISK=384KB FD: IO=0x30 UNITS=2 SD: MODE=PPI IO=0x60 DEVICES=1 SD0: SDSC NAME=SD BLOCKS=0x003C7800 SIZE=1935MB Unit Device Type Capacity/Mode ---------- ---------- ---------------- -------------------- Char 0 UART0: RS-232 38400,8,N,1 Disk 0 MD1: RAM Disk 384KB,LBA Disk 1 MD0: ROM Disk 384KB,LBA Disk 2 FD0: Floppy Disk 3.5",DS/HD,CHS Disk 3 FD1: Floppy Disk 3.5",DS/HD,CHS Disk 4 SD0: SD Card 1935MB,LBA ZETA V2 Boot Loader ROM: (M)onitor (C)P/M (Z)-System (F)orth (B)ASIC (T)-BASIC (P)LAY (U)SER ROM Disk: (0)MD1 (1)MD0 (2)FD0 (3)FD1 (4)SD0 Boot Selection?
I was pleasantly surprised how easy it is to use a TL866 programmer under Linux. minipro does all the work, though. To write and verify the whole 512K Flash ROM, it’s:
minipro -p SST39SF040 -w ZETA2_ppisd.rom
The programmer supports over 16000 devices, of which around 10000 are variants (form factor, programming voltage, speed, OTP, etc). It’ll also verify over 100 different 74-series logic chips. It’s not a super cheap device (mine was a little over $80, from Simcoe Diy) but it does a lot for that price.
Next stop: try rebuilding BBC BASIC with RomWBW’s timer support included ..
Tod Kurt’s QTPy-knob: Simple USB knob w/ CircuitPython is a fairly simple USB input project that relies on the pin spacing of an Adafruit QT Py development board being the same as that on a Bourns Rotary Encoder. If you want to get fancy (and who wouldn’t?) you can add a NeoPixel Ring to get an RGB glow.
The QT Py is based on the Seeeduino XIAO, which is a slightly simpler device than the Adafruit derivative. It still runs CircuitPython, though, and is about the least expensive way of doing so. The XIAO is drop-in replacement for the Qt Py in this project, and it works really well! Everything you need for the project is described here: todbot/qtpy-knob: QT Py Media Knob using rotary encoder & neopixel ring
I found a couple of tiny glitches in the 3d printed parts, though:
I bodged these by putting an indent in the middle of the diffuser, and filling the top D-shaft cutout with just enough Blu Tack.
Tod’s got a bunch of other projects for the Qt Py that I’m sure would work well with the XIAO: QT Py Tricks. And yes, there’s an “Output Farty Noises to DAC†one that, regrettably, does just that.
Maybe I’ll add some mass to the dial to make it scroll more smoothly like those buttery shuttle dials from old video editing consoles. The base could use a bit more weight to stop it skiting about the desk, so maybe I’ll use Vik’s trick of embedding BB gun shot into hot glue. For now, I’ve put some rubber feet on it, and it mostly stays put.
Hey! Unlike my last Seeed Studio device post, I paid for all the bits mentioned here.
It was inevitable:
brings you this wonderful creation, which plays the Nyan Cat theme forever, except it gets 20% faster each time. This is weapons-grade annoying (thank’ee kindly), so I’m not going to include a recording here. If you must hear an approximation, paste the RTTTL into Play RTTTL Online and enjoy.
# Raspberry Pi Pico RTTTL example
# nyan cat, but it gets faster
# scruss - 2021-02: sorry, not sorry ...
# Uses rtttl.py from
# github.com/dhylands/upy-rtttl
# Nyan Cat RTTTL from
# github.com/KohaSuomi/emb-rtttl/blob/master/rtttl/nyancat.rtttl
from rtttl import RTTTL
from time import sleep_ms
from machine import Pin, PWM
b = 90 # bpm variable
# pin 26 - GP20; just the right distance from GND at pin 23
# to use one of those PC beepers with the 4-pin headers
pwm = PWM(Pin(20))
led = Pin('LED', Pin.OUT)
def play_tone(freq, msec):
# play RTTL notes, also flash onboard LED
print('freq = {:6.1f} msec = {:6.1f}'.format(freq, msec))
if freq > 0:
pwm.freq(int(freq)) # Set frequency
pwm.duty_u16(32767) # 50% duty cycle
led.on()
sleep_ms(int(0.9 * msec)) # Play for a number of msec
pwm.duty_u16(0) # Stop playing for gap between notes
led.off()
sleep_ms(int(0.1 * msec)) # Pause for a number of msec
while True:
nyan = 'nyancat:d=4,o=5,b=' + str(b) + ':16d#6,16e6,8f#6,8b6,16d#6,16e6,16f#6,16b6,16c#7,16d#7,16c#7,16a#6,8b6,8f#6,16d#6,16e6,8f#6,8b6,16c#7,16a#6,16b6,16c#7,16e7,16d#7,16e7,16c#7,8f#6,8g#6,16d#6,16d#6,16p,16b,16d6,16c#6,16b,16p,8b,8c#6,8d6,16d6,16c#6,16b,16c#6,16d#6,16f#6,16g#6,16d#6,16f#6,16c#6,16d#6,16b,16c#6,16b,8d#6,8f#6,16g#6,16d#6,16f#6,16c#6,16d#6,16b,16d6,16d#6,16d6,16c#6,16b,16c#6,8d6,16b,16c#6,16d#6,16f#6,16c#6,16d#6,16c#6,16b,8c#6,8b,8c#6,8f#6,8g#6,16d#6,16d#6,16p,16b,16d6,16c#6,16b,16p,8b,8c#6,8d6,16d6,16c#6,16b,16c#6,16d#6,16f#6,16g#6,16d#6,16f#6,16c#6,16d#6,16b,16c#6,16b,8d#6,8f#6,16g#6,16d#6,16f#6,16c#6,16d#6,16b,16d6,16d#6,16d6,16c#6,16b,16c#6,8d6,16b,16c#6,16d#6,16f#6,16c#6,16d#6,16c#6,16b,8c#6,8b,8c#6,8b,16f#,16g#,8b,16f#,16g#,16b,16c#6,16d#6,16b,16e6,16d#6,16e6,16f#6,8b,8b,16f#,16g#,16b,16f#,16e6,16d#6,16c#6,16b,16f#,16d#,16e,16f#,8b,16f#,16g#,8b,16f#,16g#,16b,16b,16c#6,16d#6,16b,16f#,16g#,16f#,8b,16b,16a#,16b,16f#,16g#,16b,16e6,16d#6,16e6,16f#6,8b,8a#,8b,16f#,16g#,8b,16f#,16g#,16b,16c#6,16d#6,16b,16e6,16d#6,16e6,16f#6,8b,8b,16f#,16g#,16b,16f#,16e6,16d#6,16c#6,16b,16f#,16d#,16e,16f#,8b,16f#,16g#,8b,16f#,16g#,16b,16b,16c#6,16d#6,16b,16f#,16g#,16f#,8b,16b,16a#,16b,16f#,16g#,16b,16e6,16d#6,16e6,16f#6,8b,8c#6'
tune = RTTTL(nyan)
print('bpm: ', b)
for freq, msec in tune.notes():
play_tone(freq, msec)
b = int(b * 1.2)
I built a DS0150 — successfully, on my second try — and wanted to measure something. My demo MicroPython program from MicroPython on the terrible old ESP8266-12 Development Board has been running since May 2020, and the RGB LED’s red channel is conveniently broken out to a header. Since the DSO150 has precisely one channel, it let me see the how the PWM duty cycle affects the voltage (and brightness) of the LED.
I can’t think of oscilloscopes without being reminded of a scene from one of my favourite sci-fi books, The Reproductive System by John Sladek. Cal, the hapless new hire in the Wompler toy factory-turned-military research lab, is showing the boss some equipment while making up more and more extravagant names for them for the clueless owner:
At each exhibit, Grandison [Wompler] would pause while Cal named the piece of equipment. Then he would repeat the name softly, with a kind of wonder, nod sagely, and move on. Cal was strongly reminded of the way some people look at modern art exhibitions, where the labels become more important to them than the objects. He found himself making up elaborate names.
— The Reproductive system, by John Sladek (text copypasta from Grey Goo in the 1960s)
“And this, you’ll note, is the Mondriaan Modular Mnemonicon.â€
“—onicon, yes.â€
“And the Empyrean diffractosphere.â€
“—sphere. Mn. I see.â€
Nothing surprised Grandison, for he was looking at nothing. Cal became wilder. Pointing to Hita’s desk, he said, “The chiarascuro thermocouple.â€
“Couple? Looks like only one, to me. Interesting, though.â€
A briar pipe became a “zygotic pipette,†the glass ashtray a “Piltdown retort,†and the lamp a “phase-conditioned Aeolian.†Paperclips became “nuances.â€
“Nuances, I see. Very fine. What’s that thing, now?â€
He pointed to an oscilloscope. Cal took a deep breath.
“Its full name,†he said, “is the Praetorian eschatalogical morphomorphic tangram, Endymion-type, but we usually just call it a ramification.â€
The old man fixed him with a stern black eye. “Are you trying to be funny or something? I mean, I may not be a smart-aleck scientist, but I sure as hell know a television when I see one.â€
Cal assured him it was not a television, and proved it by switching it on. “See,†he said, pointing to a pattern of square waves, “there are the little anapests.â€
So we were displaying roughly 500 anapests/s there. Not bad, not bad at all …