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starcryo.com/mr-squid/

This is the cutest product name ever.

Since 1992, Mr. SQUID has been the standard educational demonstration system for undergraduate physics lab courses.

Used e.g. at Video "Superconducting Quantum Interference Devices by UNSW Physics (2020)"

Their manual: www.phys.ksu.edu/personal/cocke/classes/phys506/squidman.pdf

YBCO device, runs on liquid nitrogen.

Breadboard by

Ciro Santilli 40 Updated 2025-07-16

This is how electronic circuits are normally prototyped!

Once you validate them like this, the next step is usually to move on to printed circuit boards for more reliable production setups.

Breadboards are a thing of beauty and wonder.

Breadboards - Trash or Treasure? by Keysight (2020)

Source.

Arduino by

Ciro Santilli 40 Updated 2025-07-27

MakeCode Miro Bit by

Ciro Santilli 40 Updated 2025-07-16

support.microbit.org/support/solutions/articles/19000111744-makecode-python-and-micropython explains.

makecode.microbit.org

Microbit simulator using some Microsoft framework.

TODO the Python code from there does not seem to run on the microbit via uflash, because it is not MicroPython.

forum.makecode.com/t/help-understanding-local-build-options/6130 asks how to compile locally and suggests it is possible. Seems to require Yotta, so presumably compiles?

Presumably this is because Microsoft ported their MakeCode thing to the MicroBit, and the Micro Bit foundation accepted them.

E.g. there toggling a LED:

led.toggle(0, 0)

but the code that works locally is a completely differently named API set_pixel:

microbit.display.set_pixel(0, 0, )

Microsoft going all in on adopt extend extinguish from an early age!

Micro Bit getting started by

Ciro Santilli 40 Updated 2025-07-16

When plugged into Ubuntu 22.04 via the USB Micro-B the Micro Bit mounts as:

/media/$USER/MICROBIT/

e.g.:

/media/ciro/MICROBIT/

for username ciro.

Loading the program is done by simply copying a .hex binary into the image e.g. with:

cp ~/Downloads/microbit_program.hex /media/$USER/MICROBIT/

The file name does not matter, only the .hex extension.

The back power light flashes while upload is happening.

Flashing takes about 10-15 seconds for the 1.8 MB scroll display hello world from microbit-micropython.readthedocs.io/en/v1.0.1/tutorials/hello.html:

from microbit import *
display.scroll("Hello, World!")

and the program starts executing immediately after flash ends.

You can restart the program by clicking the reset button near the USB. When you push down the program dies, and it restarts as soon as you release the button.

Compile MicroPython code for Micro Bit locally on Ubuntu 22.04 with your own firmware by

Ciro Santilli 40 Updated 2025-07-27

TODO didn't manage from source Ubuntu 22.04, their setup bitrotted way too fast... it's shameful even. Until I gave up and went for the magic Docker of + github.com/bbcmicrobit/micropython, and it bloody worked:

git clone https://github.com/bbcmicrobit/micropython
cd micropython
git checkout 7fc33d13b31a915cbe90dc5d515c6337b5fa1660
docker pull ghcr.io/carlosperate/microbit-toolchain:latest
docker run -v $(pwd):/home --rm ghcr.io/carlosperate/microbit-toolchain:latest yt target bbc-microbit-classic-gcc-nosd@https://github.com/lancaster-university/yotta-target-bbc-microbit-classic-gcc-nosd
docker run -v $(pwd):/home --rm ghcr.io/carlosperate/microbit-toolchain:latest make all

# Build one.
tools/makecombinedhex.py build/firmware.hex examples/counter.py -o build/counter.hex
cp build/counter.hex "/media/$USER/MICROBIT/"

# Build all.
for f in examples/*; do b="$(basename "$f")"; echo $b; tools/makecombinedhex.py build/firmware.hex "$f" -o "build/${b%.py}.hex"; done

The pre-Docker attempts:

sudo add-apt-repository -y ppa:team-gcc-arm-embedded
sudo apt update
sudo apt install gcc-arm-embedded
sudo apt install cmake ninja-build srecord libssl-dev

# Rust required for some Yotta component, OMG.
sudo snap install rustup
rustup default 1.64.0

python3 -m pip install yotta

The line:

sudo add-apt-repository -y ppa:team-gcc-arm-embedded

warns:

E: The repository 'https://ppa.launchpadcontent.net/team-gcc-arm-embedded/ppa/ubuntu jammy Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

and then the update/sudo apt-get install gcc-arm-embedded fails, bibliography:

Attempting to install Yotta:

sudo -H pip3 install yotta

or:

python3 -m pip install --user yotta

was failing with:

Exception: Version mismatch: this is the 'cffi' package version 1.15.1, located in '/tmp/pip-build-env-dinhie_9/overlay/local/lib/python3.10/dist-packages/cffi/api.py'.  When we import the top-level '_cffi_backend' extension module, we get version 1.15.0, located in '/usr/lib/python3/dist-packages/_cffi_backend.cpython-310-x86_64-linux-gnu.so'.  The two versions should be equal; check your installation.

Running:

python3 -m pip install --user cffi==1.15.1

did not help. Bibliography:

From a clean virtualenv, it appears to move further, and then fails at:

Building wheel for cmsis-pack-manager (pyproject.toml) ... error
error: [Errno 2] No such file or directory: 'cargo'

So we install Rust and try again, OMG:

sudo snap install rustup
rustup default stable

which at the time of writing was rustc 1.64.0, and then OMG, it worked!! We have the yt command.

However, it is still broken, e.g.:

git clone https://github.com/lancaster-university/microbit-samples
cd microbit-samples
git checkout 285f9acfb54fce2381339164b6fe5c1a7ebd39d5
cp source/examples/invaders/* source
yt clean
yt build

blows up:

annot import name 'soft_unicode' from 'markupsafe'

bibliography:

Micro Bit version by

Ciro Santilli 40 Updated 2025-07-16

Identification: kitronik.co.uk/blogs/resources/explore-micro-bit-v1-microbit-v2-differences The easiest thing is perhaps the GPIO notches.

Micro Bit example by

Ciro Santilli 40 Updated 2025-07-16

microbit/micropython/uart.py: the Micro BIt comes with a UART simulator via the USB connection, it is very convenient: support.microbit.org/support/solutions/articles/19000022103-outputing-serial-data-from-the-micro-bit-to-a-computer To output data to the computer simply use Python print. To receive you can e.g. use GNU screen:
```
screen /dev/ttyACM0 115200
```
It appears to be very unreliable however, some times it shows up, sometimes it doesn't.

Micro Bit GPIO by

Ciro Santilli 40 Updated 2025-07-16

Pinout overview: makecode.microbit.org/device/pins Basically 0, 1, and 2 are the truly generic ones. They can also serve as ADCs.

Micropython documentation: microbit-micropython.readthedocs.io/en/latest/pin.html

Devboard battery power by

Ciro Santilli 40 Updated 2025-07-16

Many devborads require a 5V power supply.

This is common on wall transformers and USB, but not in batteries.

For battery power you need a transformer.

Raspberry Pi Battery Power by ExplainingComputers (2021)

Source.

Elliptic-curve Diffie-Hellman by

Ciro Santilli 40 Updated 2025-07-16

The algorithm is completely analogous to Diffie-Hellman key exchange in that you efficiently raise a number to a power

n

times and send the result over while keeping

n

as private key.

The only difference is that a different group is used: instead of using the cyclic group, we use the elliptic curve group of an elliptic curve over a finite field.

Elliptic curves by Computerphile (2018)

Source. youtu.be/NF1pwjL9-DE?t=143 shows the continuous group well, but then fails to explain the discrete part.

Variant of Diffie-Hellman key exchange based on elliptic curve cryptography.

Point-to-point construction by

Ciro Santilli 40 Updated 2025-07-16

Analog-to-digital converter by

Ciro Santilli 40 Updated 2025-07-16

Many/most microcontroller boards have analog-to-digital converters built into them, it is very convenient. E.g. it is the case for the Raspberry Pi Pico.

Prize by

Ciro Santilli 40 Updated 2025-07-16

Generally, prizes that pay big lumps of money to well established individuals are a bit useless, it would be better to pay smaller sums to struggling beginners in the field, of which there are aplenty.

The most important part about prizes should not be the money, nor the recognition, but rather explaining better what the laureates did. In this, most prizes fail. Thus Ciro Santilli's project idea: Project to explain each Nobel Prize better.

Ah, this list: en.wikipedia.org/wiki/List_of_prizes_known_as_the_Nobel_or_the_highest_honors_of_a_field

Open source analog-to-digital converter by

Ciro Santilli 40 Updated 2025-07-16

Open Source 8.5 Digit Voltmeter from CERN by Marco Reps (2021)

Source.

Digital electronics by

Ciro Santilli 40 Updated 2025-07-16

Digital electronic circuit by

Ciro Santilli 40 Updated 2025-07-16

Frequency divider by

Ciro Santilli 40 Updated 2025-07-16

An LC circuit is analogous to a spring-mass system by

Ciro Santilli 40 Updated 2025-07-16

Both are harmonic oscillators.

In the LC circuit:

the current current may be seen as the velocity and containing the kinetic energy
the charge stored in the capacitor as the potential energy

You can kickstart motion in either of those systems in two ways:

charge the capacitor, i.e. pull the string, and then let it go, i.e. close the circuit. This is the simpler one to realise. Shown concretely at: Video "LC circuit dampened oscillations on an oscilloscope by Queuerious Guy (2014)"
give speed to the mass, i.e. make a current pass through the inductor

RLC circuit by

Ciro Santilli 40 Updated 2025-07-16

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