Ciro Santilli @cirosantilli  40

These can be used to break cells apart from tissue, and also break up larger DNA or RNA molecules into smaller ones, suitable for sequencing.

Basically, the antenna has to be very, very large, more comparable to wavelength. E.g. even for the higher pitches, we fall in very low frequency, so have a look at the size of some of the submarine VLF antennas! They are like football pitch sized.

Early transmitters such as the spark-gap transmitter could only send noises to send Morse code.

To send voice and music, amplitude modulation had to be developed. And a key ingredient of this is the carrier wave.

The problem is, the carrier wave needs to have somewhat high frequencies, in the hundreds of kHz TODO why. But as you might imagine, that is hard to achieve by mechanical means such as a hand cranck like Hippolyte Pixiis alternator!

Interestingly, some of the first carrier wave generators were actually mechanical, e.g. the Alexanderson alternator.

But clearly such mechanical machines were not very scalable, and soon more electronic devices were introduced, notably the vacuum tube.

One of the brightest natural objects in the sky, and by far the brightest not in the Milky Way! This is partly because it is relatively close to us.

Contains instructions on how to synthesize MIDI.

Extension: sf2.

Can be imported for example by:

Opens a virtual MIDI piano GUI. It just works on Ubuntu 20.04: askubuntu.com/questions/34391/virtual-midi-piano-keyboard-setup/1298026#1298026

VMPK is a virtual device that replicates what you would get by connecting a physical MIDI keyboard to your computer. It is not a software synthesizer on its own. But it does connect to a working synthesizer by default (Sonivox EAS) which makes it produce sounds out-of-the box.

TODO: then I messed with my sound settings, and then it stopped working by default on the default "MIDI Connection" > "MIDI Out Driver" > "Network". But it still works on "SonivoxEAS".

A hello world of actually connecting it to a specific software synthesizer manually on Advanced Linux Sound Architecture with aconnect can be found at: askubuntu.com/questions/34391/virtual-midi-piano-keyboard-setup/1298026#1298026

Save to a MIDI file: askubuntu.com/questions/709673/save-as-midi-when-playing-from-vmpk-qsynth/1298231#1298231

Reasonable default key mappings to keyboard covering 2 octaves.

3 multiple simultaneous keys did not work (tested "ZQI"). This might just be a limitation of my keyboard however.

TODO how to save to a .mid file? askubuntu.com/questions/709673/save-as-midi-when-playing-from-vmpk-qsynth

SourceForge.

Bluetooth support: not enough RAM for it, though in principle its chip/transceiver could support it! microbit-micropython.readthedocs.io/en/v1.0.1/ble.html

Supported editors: microbit.org/code/

MicroPython web editor and compiler: python.microbit.org/v/2

Everything in this section is tested on the Micro Bit v1 from Micro Bit v1 unless otherwise noted.

Bibliography:

In the 2010's/2020's, many people got excited about getting children in to electronics with cheap devboards, notably with Raspberry Pi and Arduino.

While there is some potential in that, Ciro Santilli always felt that this is very difficult to do, while also keeping his sacred principle of backward design in mind.

The reason for this is that "everyone" already has much more powerful computers at hand: their laptops/desktops and even mobile phones as of the 2020s. Except perhaps if you are thing specifically about poor countries.

Therefore, the advantage using such devboards for doing something that could useful must come from either:

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.

Study of the metabolome.