work as if you live in the early days of a better nation
This is great: gdsports/midiuartusbh: MIDI DIN to MIDI USB Host Converter allows your USB MIDI instruments to act as traditional MIDI controllers. It uses a Adafruit Trinket M0 to act as the USB host and MIDI output.
I modified gdsports’ design very slightly:
And it works!
This message from an unknown caller has sat on our landline answering machine since 2020 or 2021. No idea who or what sent it. All I know is it came in just before noon on a Tuesday morning. The entirely synthesized voice makes me think it’s a junk call, but there’s no scam attached. Just this message, slightly eerie, quite inexplicable.
In early 2013, I must’ve been left unsupervised for too long since I made The Quite Rubbish Clock:
Written in (Owen Wilson voice) kind of an obsolete vernacular and running on hardware that’s now best described as “quaint”, it was still absurdly popular at the time. Raspberry Pis were still pretty new, and people were looking for different things to do with them.
I happened across the JASchilz/uQR: QR Code Generator for MicroPython the other day, and remembered I had some tiny OLED screens that were about the same resolution as the old Nokia I’d used in 2013. I wondered: could I …?
The board is a LOLIN S2 Mini with a OLED 0.66 Inch Shield on top, all running MicroPython. One limitation I found in the MicroPython QR library was that it was very picky about input formats, so it only displays the time as HHMMSS with no separators.
Source, of course:
# -*- coding: utf-8 -*-
# yes, the Quite Rubbish Clock rides again ...
# scruss, 2022-06-30
# MicroPython on Lolin S2 Mini with 64 x 48 OLED display
# uses uQR from https://github.com/JASchilz/uQR
# - which has problems detecting times with colons
from machine import Pin, I2C, RTC
import s2mini # on Lolin ESP32-S2 Mini
import ssd1306
from uQR import QRCode
WIDTH = 64 # screen size
HEIGHT = 48
SIZE = 8 # text size
r = RTC()
# set up and clear screen
i2c = I2C(0, scl=Pin(s2mini.I2C_SCL), sda=Pin(s2mini.I2C_SDA))
oled = ssd1306.SSD1306_I2C(WIDTH, HEIGHT, i2c)
oled.fill(0)
def snazz():
marquee = [
" **",
" **",
" **",
" **",
" **",
"********",
" ******",
" ****",
" **",
" quite",
"rubbish",
" clock",
" mk.2",
"<scruss>",
" >2022<"
]
for s in marquee:
oled.scroll(0, -SIZE) # scroll up one text line
oled.fill_rect(0, HEIGHT-SIZE, WIDTH,
SIZE, 0) # blank last line
oled.text("%-8s" % s, 0, HEIGHT-SIZE) # write text
oled.show()
time.sleep(0.25)
time.sleep(5)
oled.fill(1)
oled.show()
snazz() # tedious crowd-pleasing intro
qr = QRCode()
while True:
qr.add_data("%02d%02d%02d" % r.datetime()[4:7])
qr.border = 1 # default border too big to fit small screen
m = qr.get_matrix()
oled.fill(1)
for y in range(len(m)):
for x in range(len(m[0])):
# plot a double-sized QR code, centred, inverted
oled.fill_rect(9 + 2*x, 1 + 2*y, 2, 2, not m[y][x])
oled.show()
time.sleep(0.05)
qr.clear()
If your output is glitchy, you might need to put the following in boot.py:
import machine
machine.freq(240000000)
This increases the ESP32-S2’s frequency from 160 to 240 MHz.
The Internet Archive has Threlkeld Granite Co Ltd’s Album of ornamental granitic tiles online, and I’m really digging the patterns of the hydraulic tiles they made. I’ve recreated some of their patterns in InkScape, and made this small demo by tiling bitmapped renderings.
Rob Cruickshank noted the other day:
Naturally, I had to verify this. So I tuned to the WWV 10 MHz time signal on my amateur rig, tuned a portable radio to CBC Radio 1 FM, which broadcasts on 99.1 MHz in Toronto and recorded them together:
Yup: Rob’s right – CBC is broadcasting the NRC 13:00:00 signal at 13:00:10, which for time nerds might as well be the change from Julian to the Gregorian calendar.
This recording was made directly from the airwaves. There should be effectively no difference between the signal broadcast times, but here we are with the “National Research Council official time signal” going out at a very wrong time indeed.
Update, October 2023: Well, CBC has noticed, and rather than trying to fix it, they’re going to end it: The end of the long dash: CBC stops broadcasting official time signal | CBC News
Following on from a customer query at Elmwood Electronics, I can confirm that one can install install addressable RGB LEDs/NeoPixels inside one of these large buttons. It’s not the easiest build, so whether one should attempt this is another matter entirely.
You’ll need:
I’m not going to cover soldering the wires to the LED PCB in any depth here. You’ll need three wires: 5 V power, Ground and Data. Even though the LEDs I used need 5 V power, they are quite happy with 3.3 V logic on the data line. They need more than 3.3 V power to light, though.
PDF, too, if you like such things: record_label_jali.pdf. Made with OpenSCAD.
Simulated (and not quite right yet) output from a “HOOT-NANNY” or Magic Designer, a proto-Spirograph toy that drew six-sided curves on round paper sheets. It was made by Howard B. Jones and Co. of Chicago, IL and first sold in 1929. The company’s better known for producing Jones Plugs and Sockets, sometimes known as Cinch-Jones connectors. The “HOOT-NANNY” name was dropped when production moved to the Northern Signal Company of Saukville, WI.
My eBay-acquired Magic Designer is quite beaten up, and doesn’t always produce accurate results. Here’s how one should look, from the instruction pamphlet:
As far as I’ve been able to work out, the parameters of the machine are:
If we model the toy with a fixed turntable:
Here’s a very simple model in Python that emits a hard-coded (but editable) pattern in HP-GL: Slightly imperfect Python simulation of the “HOOT-NANNY” (or Magic Designer) drawing toy (static local copy: hootnanny.zip). It doesn’t do anything with the fixed circle studs (yet)
It’s unlikely anyone wanted a faux-lineprinter ASCII art calendar for 2022, but you’re getting one anyway. You can print this yourself:
If you want to make your own, here’s a script: snoopycal.sh
Credits:
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…?
… only to realize I don’t really like circular key grids.
So I ported autumn in canada from OpenProcessing to PicoMite BASIC on the Raspberry Pi Pico:
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.
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:
Slides from last night’s talk:
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:
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.
What you can’t see is the smell of Halloween: the hum of charred turnip from the candle inside.
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.
Running stock Raspberry Pi OS with desktop, compiled with stock options:
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
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.
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.)
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:
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.
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 …