I’m still a sucker for vase mode/spiral contour prints … this one made in OpenSCAD:
Thanks to Andrew at ProtoLab for the loan of the PrintrBot. I’ve got a demo at UofT on Wednesday, and my Reach 3D isn’t exactly portable. Yeah, I should probably get a cheap Monoprice printer to lug around to occasional demos, but I’d need to find a donor …
Thingiverse‘s Customizer allows users to customize suitable OpenSCAD models without knowing any OpenSCAD code. While it does have some documentation to help developers along, there’s still a lot of guesswork.
I released my first (working!) Customizer design the other week: Parametric Finger Pen Holder (Vertical). While the docs are the primary source of developer information, you might want to know the following:
Thanks to users sbadger and lurkio on the stardot forum, I’ve been reunited the original BBC BASIC one-liner that begat 2d Star Dodge/Stardodger: Asterisk Tracker!
It was published in the December 1984 edition of BEEBUG Magazine (vol. 3, issue 7; page 9) and is credited to N. Silver.
It’s impossibly short:
1L=0:REP.L=L+3:MO.4:DR.1279,0:DR.1279,452:MOVE1279,572:DR.1279,1023:DR.0,1023:F.I=1TOL:V.31,RND(32)+5,RND(31),42,30:N.:P.(L-3)/3:X=0:Y=512:REP.PL.69,X,Y:X=X+4:Y=Y-(INKEY-74+.5)*8:U.PO.X,Y)=1ORX=1280:U.X<1280:V.7:REP.U.INKEY-99:RUN
It makes extensive use of BBC BASIC’s abbreviations, and the writeup even warns
… Here the programs are extensively abbreviated so that the line will fit into Basic’s keyboard buffer. Because of this, you cannot edit a LISTed version, and so, to allow for errors, it is best to spool out a copy of the text to tape/disc initially. This can be achieved as follows:
*SPOOL PROGRAM
type in program
*SPOOL
The program unwinds to something much more understandable:
10 L=0
20 REPEAT
30 L=L+3
40 MODE 4
50 DRAW 1279,0
60 DRAW 1279,452
70 MOVE 1279,572
80 DRAW 1279,1023
90 DRAW 0,1023
100 FOR I=1 TO L
110 VDU 31,RND(32)+5,RND(31),42,30
120 NEXT
130 PRINT (L-3)/3
140 X=0
150 Y=512
160 REPEAT
170 PLOT 69,X,Y
180 X=X+4
190 Y=Y-(INKEY(-74)+.5)*8
200 UNTIL POINT(X,Y)=1 OR X=1280
210 UNTIL X<1280
220 VDU 7
230 REPEAT UNTIL INKEY(-99)
240 RUN
The instructions are typical of the day:
The first game (called “Asterisk Tracker”) is a very simple game in which you have to guide a “snake” across the screen, whilst avoiding the stars. As the game progresses, more and more stars will be displayed, and the ease of the game rapidly disappears. The Return key guides the “snake” upwards, but it moves down if Return is not pressed. Aim your “snake” for the gap in the wall, and don’t touch any objects as this causes instant death from space acid poisoning!
Um, yeah, N. Silver, whatevs …
It’s pretty amazing that three type-ins could fit on a page: especially when you consider that the BEEBUG magazine was A5!
If you want to play it (and who wouldn’t? We wasted days on this game) you can either run this Asterisk Tracker alone in the browser: Asterisk Tracker, or lurkio has combined them into one, and put them here: Beebug One-Line Games (Asterisk Tracker, a Truffle Hunt clone, and a treasure hunt).
I just wish Graeme Smith were still with us to play this.
but this still owns it:
I found I can get this to preload in an emulator, but you still have to type RUN and hit return. See, look: http://scruss.com/cpc/6128s.html?stardoj.dsk/10%20PRINT%20CHR$(199+2*RND);:%20GOTO%2010
Even though this plot is only about the size of a postcard, it took around 1½ hours to plot …
Rob’s British Council Tile / Bus Fabric Sim — described here: Amstrad BASIC that approximates the tiling schemes that a local council might have used for a municipal building in the 1970s — is a joy. So few colours!
Because I care (and don’t if you don’t), here’s the Locomotive BASIC source, lovingly typed into the Caprice32 emulator then extracted as text using iDsk:
10 ' British Council Tile / Bus Fabric Sim
20 ' by Rob Manuel 2018
30 '
40 ' z/x - change char up/down (ascii)
50 ' space - random palette
60 ' c - show ascii val, inks & pause
70 ' v - random character (128+ ascii)
80 ' b - random char and cols
90 ' n - fill with same line & pause
100 'i - input ascii value
110 '
120 ON BREAK GOSUB 260:MODE 1:LOCATE 1,26
130 DEF FNs=INT(RND*255)
140 SYMBOL 255,FNs,FNs,FNs,FNs,FNs,FNs,FNs,FNs
150 DEF FNp=INT(RND*4)
160 DEF FNi=INT(RND*26)
170 GOSUB 470
180 GOSUB 270
190 o$="":i$=INKEY$
200 IF i$<>"" THEN GOSUB 380
210 FOR i=1 TO 40
220 w$=CHR$(14)+CHR$(FNp)+CHR$(15)+CHR$(FNp)
230 w$=w$+CHR$(c):o$=o$+w$:NEXT i
240 store$=o$
250 PRINT o$;:GOTO 190
260 CALL &BC02:PAPER 0:PEN 1:END
270 aa=FNi:bb=FNi:cc=FNi:dd=FNi
280 INK 0,aa:INK 1,bb:INK 2,cc:INK 3,dd
290 BORDER aa
300 GOSUB 320:RETURN
310 IF c>255 THEN c=32:IF c<32 THEN c=255
320 LOCATE 1,1:PAPER 0:PEN 1
330 PRINT "C:"c;
340 PRINT CHR$(c);
350 PRINT " ";
360 PRINT "I:"aa;bb;cc;dd;
370 LOCATE 1,26:RETURN
380 IF i$=" " THEN GOSUB 270:RETURN
390 IF i$="z" THEN c=c-1:GOSUB 310:RETURN
400 IF i$="x" THEN c=c+1:GOSUB 310:RETURN
410 IF i$="c" THEN GOSUB 310:CALL &BB18:RETURN
420 IF i$="i" THEN LOCATE 1,1:INPUT "ASCII?",c:GOSUB 310:RETURN
430 IF i$="v" THEN GOSUB 470:GOSUB 310:RETURN
440 IF i$="b" THEN GOSUB 270:GOSUB 470:GOSUB 310:RETURN
450 IF i$="n" THEN FOR i=1 TO 25:PRINT store$;:NEXT:CALL &BB18:RETURN
460 RETURN
470 c=INT(RND*128)+127:RETURN
And if you really care, here’s an emulator snapshot — BritishCouncilTileSim.zip
Update: I modified the code slightly (essentially, all INT(RND*n) to RND MOD n) so it would compile with Hisoft Turbo Basic. It works! It’s faster!
Snapshot: BritishCouncilTileSimCompiled.zip
Unless you have the heavy analogue Apple CRT that was specially made for it, composite video output on the Apple IIgs is utterly dismal:
Adding an Apple IIgs → SCART cable through a SCART to HDMI converter is much better:
There’s still a little bit of shimmer to the background, but at least text is legible.
Yup, lots of circles, intersections, differences and offsets went into this attempt at the logo of my favourite museum.
For the determined/demented, here’s the source. It’s probably not that useful for learning OpenSCAD, as it’s written in my typical “carve away all the bits that don’t look like an elephant†style:
// akm logo - why yes this *is* a good tool to use ...
// constants for octagon maths
r1 = 1 - sqrt(2) / 2; // ~0.292893
r2 = sqrt(r1); // ~0.541196
x1 = (sqrt(2) - 1) / 2; // ~0.207107
sc = 100; // size factor
t = 4; // line thickness
bigt = 7; // strapwork gap thickness
$fn = 256; // OpenSCAD circle smoothness
module petal() {
intersection() {
translate([ sc * x1, sc * x1])circle(r = sc * r2);
translate([-sc * x1, sc * x1])circle(r = sc * r2);
}
}
module hollow_petal() {
difference() {
offset(r = t / 2)petal();
offset(r = -t / 2)petal();
}
}
module inner_lobe() {
difference() {
for (i = [0:3]) {
rotate(i * 90 + 45)offset(r = t / 2)petal();
}
for (i = [0:3]) {
rotate(i * 90 + 45)offset(r = -t / 2)petal();
}
}
}
module ring() {
for (i = [0:3]) {
rotate(i * 90)difference() {
intersection() {
inner_lobe();
union() {
offset(r = -bigt / 2)petal();
rotate(45)offset(r = t / 2)petal();
}
}
rotate(90)offset(r = bigt / 2)petal();
}
}
}
module logo() {
union() {
ring();
for (i = [0:3]) {
rotate(90 * i)union() {
intersection() {
hollow_petal();
rotate(-90)offset(r = -bigt / 2)petal();
}
difference() {
intersection() {
hollow_petal();
rotate(45)offset(r = -bigt / 2)petal();
}
rotate(-90)offset(r = bigt / 2)petal();
}
difference() {
hollow_petal();
offset(r = bigt / 2)union() {
rotate(-90)petal();
rotate(45)petal();
}
}
}
}
}
}
logo();
I use a FlashForge Creator Pro 3D printer for work. It’s okay, but I wouldn’t recommend it: you have to manually level the print bed (ಠ_ಠ), you can’t print via USB, it pretends to be a knock-off MakerBot (same USB ID: naughty naughty) and its slicing software is a mishmash of GPL and other code all bundled up in one proprietary lump. It also doesn’t used g-code, which is a bit poo.
I have been having endless trouble will tall prints losing adhesion, falling over, and leaving a noodly mess everywhere. I’ve fixed it by making some manual changes to the config file, the process as described here: Flashprint advanced print settings by editing the default.cfg configuration file. What I changed was:
[brim] enable = true # valid range {true, false}, default is false # CHANGED extruderId = 0 # valid range {0, 1}, default is 0 margin = 10.0 # valid range [1.0, 10.0], default is 5.0 # CHANGED layerCnt = 2 # valid range [1, 5], default is 1 # CHANGED speed = 60 # valid range [10, 200], default is 60 excludeInterior = true # valid range {true, false}, default is false # CHANGED
This makes a colossal double-width, double thickness brim around the prints so that they will not topple. I’m very happy with the results so far.
Rather than mucking about with config files, if you enable “Expert Mode” in Flashprint’s preferences:
Then you can make a brim that stops prints coming off the print bed.
And lo, there was much rejoicing …
Eugene “thirtytwoteeth” Andruszczenko (of Game Boy Zero – Handheld Edition fame) posted a neat idea to help your Raspberry Pi Zero take jumper wires without soldering. He threaded fishing line through the 40 hole header, making an interference fit for header pins. I tried it with 0.38 mm Trilene, which worked rather well.
Instagram filter used: Lo-fi
… which of course failed 95% through:
You gotta brim all the time.
source by Dan Anderson: https://www.openprocessing.org/sketch/519299
Enlarged and plotted on a Roland DXY pen plotter: 0.7 mm black pen on design vellum.
Full page:
Even if the 0.7 mm pen is a bit chunky for fine guilloché effects, the plotter output is pretty crisp. Here’s a detail at full resolution:
Unfortunately, an earlier attempt to print this figure using a fresh-out-the-box 20+-year-old HP SurePlot ¼ mm pen on glossy drafting paper resulted in holes in the paper and an irreparably gummed-up pen. If anyone knows how to unblock these pens, I’m all ears …
This is one of those toys that you whirl around on a piece of string and it makes a chirping sound like a flock of sparrows. I have no idea what they’re called, so I called it birb_chirper.
Printer: Reach 3D
Rafts: Doesn’t Matter
Supports: Doesn’t Matter
Resolution: 0.3 mm
Infill: 0%
Notes: This is a thin-walled model, so use at least two shells and no infill for smooth walls.
Take a piece of thin string about 1 metre long (I used micro-cord, very fine paracord), pass it through the hole in the tip, then tie off a jam knot that’s big enough to stop in the hole in the top but still pass back through the slot in the side. Now whirl the thing around fast by the string, and it should start to chirp.
This is intended for the amusement of small children and the annoyance of adults.
The tip of this thing is an ogee curve. I’ve included my library for creating simple ogee and ogive profiles in OpenSCAD.
// ogive-ogee example
// scruss, 2018
use <ogive_and_ogee.scad>;
ogive(20, 35);
translate([0, -5])text("ogive(20,35)", size=3);
translate([30, 0])ogee(20, 35);
translate([30, -5])text("ogee(20,35)", size=3);
Download: Thingiverse —birb_chirper by scruss. Local copy: birb_chirper.zip
I might not have Amiberry — an optimized Amiga emulator for Raspberry Pi — running quite yet, but the build instructions at midwan/amiberry are a bit lacking. If you want to compile it under Raspbian Stretch, you’ll need the following packages:
sudo apt install libsdl2-dev libxml2-dev libxml2-utils libsdl2-ttf-dev libsdl2-image-dev
This will at least allow you to get it to build correctly with:
make -j2 PLATFORM=rpi3-sdl2-dispmanx
More later when/if I get it working.
The Unofficial CP/M Web site uses some very old file formats. As almost no-one can easily run Amà 3 to read the manuals these days, here are the CP/M 3.1 manuals from that site converted to PDF:
Update, 2019-01: raspblocks.com appears to be dead, with an “Account Suspended” error from the host
Raspblocks is a new Blocks-based web programming environment for Raspberry Pi. You don’t even need to write the code on a Raspberry Pi, but the Python 3 code it produces will need to be transferred to a Raspberry Pi to run.
For maximum authenticity (and slowness), I fired up http://www.raspblocks.com/ on a Raspberry Pi Zero over VNC. It took a minute or more to load up the site in Chromium, but creating a simple program was all easy dragging and dropping:
The code it produced was pretty much exactly what you’d write by hand:
import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(26, GPIO.OUT) while True: GPIO.output(26,True) time.sleep(1) GPIO.output(26,False) time.sleep(1)And, as you might expect, the code make an LED connected to GPIO 26 turn on and off. Science!
Raspblocks isn’t as polished as its more established rival EduBlocks, but Raspblocks doesn’t need any software installed. Edublocks installs its own Node.js-based web service, which would be painfully slow on a Raspberry Pi Zero. Raspblocks’ code needs to be run manually from a terminal, but I’d put up with that any day over having yet another Node server distribution installed under /opt.
SoX can do almost anything with audio files — including synthesize audio from scratch. Unfortunately, SoX’s syntax is more than a bit hard to follow, and the manual page isn’t the most clear. But there is one example in the manual that gives a glimpse of what SoX can do:
play -n synth pl G2 pl B2 pl D3 pl G3 pl D4 pl G4 \
delay 0 .05 .1 .15 .2 .25 remix - fade 0 4 .1 norm -1
While it plays a nice chord, it’s not obvious how to make audio files from this process. I have a project coming up that needs a few simple guitar chords, and with much trial and error I got SoX to spit out audio files. Here’s what I keyed into the shell:
cat guitar.txt | while read chord foo first third fifth
do
echo "$chord" :
sox -n \
-r 16000 -b 16 "chord-${chord}.wav" \
synth pl "$first" pl "$third" pl "$fifth" \
delay 0 .05 .1 \
remix - \
fade 0 1 .095 \
norm -1
done
with these lines in the file “guitar.txtâ€
G : G2 B2 D3 C : C3 E3 G4 D : D3 F#4 A3 F : F3 A3 C4 A : A3 C#4 E4 E : E2 G#3 B3 Em : E2 G3 B3
How the SoX command line breaks down:
The chords don’t sound great: they’re played on only three strings, so they sound very sparse. As my application will be playing these through a tiny MEMS speaker, I don’t think anyone will notice.
Update: well, now I know how to do it, why not do all 36 autoharp strings and make the “magic ensues†sound of just about every TV show of my childhood?
Glissando up:
sox -n -r 48000 -b 16 autoharp-up.wav synth pl "F2" pl "G2" pl "C3" pl "D3" pl "E3" pl "F3" pl "F#3" pl "G3" pl "A3" pl "A#3" pl "B3" pl "C4" pl "C#4" pl "D4" pl "D#4" pl "E4" pl "F4" pl "F#4" pl "G4" pl "G#4" pl "A4" pl "A#4" pl "B4" pl "C5" pl "C#5" pl "D5" pl "D#5" pl "E5" pl "F5" pl "F#5" pl "G5" pl "G#5" pl "A5" pl "A#5" pl "B5" pl "C6" delay 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75 remix - fade 0 6 .1 norm -1
Glissando down:
sox -n -r 48000 -b 16 autoharp-down.wav synth pl "C6" pl "B5" pl "A#5" pl "A5" pl "G#5" pl "G5" pl "F#5" pl "F5" pl "E5" pl "D#5" pl "D5" pl "C#5" pl "C5" pl "B4" pl "A#4" pl "A4" pl "G#4" pl "G4" pl "F#4" pl "F4" pl "E4" pl "D#4" pl "D4" pl "C#4" pl "C4" pl "B3" pl "A#3" pl "A3" pl "G3" pl "F#3" pl "F3" pl "E3" pl "D3" pl "C3" pl "G2" pl "F2" delay 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75 remix - fade 0 6 .1 norm -1
Could maybe use some reverb in there for the ultimate nostalgic effect.
I’m talking at the Raspberry Pi Toronto Meetup tonight, and if all goes well, the Net-Connected Cowbell will make an appearance:
My slides: MQTT.odp
Links:
