Ciro Santilli's hardware ELEGOO Upgraded Electronics Fun Kit Updated 2025-07-27
2022-10 ELEGOO Upgraded Electronics Fun Kit www.elegoo.com/products/elegoo-electronics-fun-kits-4-versions Manuals:
- Elegoo Breadboard power supply module MB‐V2:TODO center positive or center negative?Does not come with AC adapter, getting this one: www.amazon.co.uk/dp/B08ZN476FW output: DC 9V 1A Power Supply Adapter, Plug 5.5mm x 2.1mm, Center Positive,B rand: Security-01, input: AC 100-240V 50/60 Hz, Cable length: 1.8mParts list from the ZIP:
- resistors:
- 1n4007 General Purpose Rectifier
- 22pf 104 Ceramic Capacitor
- 4N35 optocoupler
- 74HC595 8-bit serial-in, serial or parallel-out shift register with output latches; 3-state
- Active buzzer
- Buttons
- CDS-55 Photoresistor
- Electrolytic Capacitor
- Focusens MF52D 103f 3950 thermistor. Beta value 25/50 Celcius: 3950. R_25: I measured 9.61 k Ohms. The number 103 they document as:These descriptions are weird, but ChatGPT has the theory that the first two digits are actual values, and the last is multiplier, so which makes 10k.
but I have no idea how that maps to 10 k Ohms. - PN2222 General Purpose Transistor
- Passive buzzer
- 3386p Bourns Precision Potentiometer - 1 103T: from 0 to 10k Ohms, measured with multimeter. According to the manual the "103" mean 10 k oms, which is consistent with our measurement. "P 103" is etched into the part.
- LEDs:
Ciro Santilli's hardware Mechanical and electrical tools Updated 2025-07-16
2020-01 www.amazon.co.uk/dp/B07D318N7Z
2020-01 "Heat Gun, SEEKONE Professional 2000W 50℃- 600℃ Variable Temperature Control Hot Air Gun Kit with 2 Temperature Modes 7 Accessories for D" www.amazon.com/dp/B078S5QMFG Initially for for cell phone repair, but later learnt they are also useful for heat shrink.
2020-11 BOA 13-2612 Strap Wrench, 6-Inch Capacity 8-Inch Long Lever www.amazon.com/dp/B00096JDKS Official: www.boatoolcorp.com/our-products/boa-constrictor-range/boa-constrictor/
2019-09 "Draper Redline 68001 160 mm Heavy Duty Pliers Set with Soft Grip Handles (3-Piece)" web.archive.org/web/20190903191215/https://www.amazon.co.uk/dp/B071JL6LLL (archive)
2019-08: www.amazon.co.uk/dp/B000LFRYG2 (archive) "Silverline SP1236 Combination Spanner, 8-19 mm - 12 Pieces" 8.48 pounds. Because I needed the 15mm for bike pedal, and the price of 1 and the full set were very close.
6 10/11/12/13/14/17 mm Combination Wrench Set WRENCH SET COMBINATION Open-Ended Spanner/Ring Spanner Set www.amazon.co.uk/dp/B07BZLVGX8 (archive) But they sent one wrong, 8 instead of 11. Chrome Vanadium Steel. Markings: "DROP FORGED A". Quality feels crappy, not very smooth.
2017: Teng 621011 Double Open Ended Spanner 10x11mm www.amazon.co.uk/dp/B0001P0VP8 (archive)
2017: Magnusson AMS49 5M TAPE MEASURE 5m retractable flexible rule. www.screwfix.com/p/magnusson-ams49-5m-tape-measure/5315v (archive)
Ciro Santilli's hardware Motorola Moto G6 Play (2018) Updated 2025-07-16
www.gsmarena.com/motorola_moto_g6_play-9002.php Upgradable to Android 9.
2023-10: unable to connect to Giffgaff. "Network unavailable". Same SIM works in other phones. So annoying. Update APN to match: www.giffgaff.com/help/articles/internet-apn-settings-guide. Went next to a tower and then got signal. So the receiver is much worse than the pixel one. Vibration appears to be broken.
Group of Lie type Updated 2025-07-16
In the classification of finite simple groups, groups of Lie type are a set of infinite families of simple lie groups. These are the other infinite families besides te cyclic groups and alternating groups.
A decent list at: en.wikipedia.org/wiki/List_of_finite_simple_groups, en.wikipedia.org/wiki/Group_of_Lie_type is just too unclear. The groups of Lie type can be subdivided into:
- Chevalley groups
- TODO the rest
The first in this family discovered were a subset of the Chevalley groups by Galois: , so it might be a good first one to try and understand what it looks like.
TODO understand intuitively why they are called of Lie type. Their names , seem to correspond to the members of the classification of simple Lie groups which are also named like that.
But they are of course related to Lie groups, and as suggested at Video "Yang-Mills 1 by David Metzler (2011)" part 2, the continuity actually simplifies things.
Primarily bought to make borlotti beans!!!
Ciro Santilli's hardware Samsung MZVLB512HAJQ-000L7 512GB SSD Updated 2025-07-16
PCIe TLC OPAL2.
www.samsung.com/semiconductor/global.semi/file/resource/2018/05/PM981_M.2_SSD_Datasheet_v1.3_for_General.pdf | web.archive.org/web/20181224225410/https://www.samsung.com/semiconductor/global.semi/file/resource/2018/05/PM981_M.2_SSD_Datasheet_v1.3_for_General.pdf
sudo hdparm -Tt /dev/nvme0n1p5 on Ubuntu 20.04: Timing cached reads: 29812 MB in 1.99 seconds = 15007.00 MB/sec
HDIO_DRIVE_CMD(identify) failed: Inappropriate ioctl for device
Timing buffered disk reads: 6328 MB in 3.00 seconds = 2109.00 MB/sec Ciro Santilli's hardware Skullcandy Smokin' Buds 2 Updated 2025-07-16
2023-07: one of the sides broke near center, rebuying.
2021-07: wire half broke near connector, only works in some positions. The funny thing is: only voices seem to be blocked out! Rebuying.
2021-06: a small bottom piece of the left earpiece broke. Wire seems find, that is like a little extension to protect wire. Let's see for how long.
2020-20: wires at one of ears broke, not sure how.
Look they looked exactly like: "Skullcandy Smokin' Buds 2 In-Ear Audio Earbud Headphones with In-Line Microphone - Black".
Re-buying that one 10 pounds:
Tech specs:
Connection Type: 3.5mm AUX CableImpedence: 32 ohmsDriver Diameter: 9mmSound Pressure Level: 95 dB (1mW/500Hz)Frequency Response: 20kHz - 20HzHeadphone Type: In-Ear
Guqin player Updated 2025-07-16
Ciro Santilli's hardware TP Link ARCHER VR2800 Updated 2025-07-16
Manual: www.tp-link.com/uk/support/download/archer-vr2800/ In particular, the user guide: static.tp-link.com/1910012125_Archer%20VR2800(EU)_V1_UG.pdf
Admin IP address: 192.168.1.1/ It also works over Wifi and people don't know how to disable that: community.tp-link.com/en/home/forum/topic/1460
Ciro Santilli's legs sometimes itch when he runs Updated 2025-07-16
Ciro Santilli has an undiagnozed condition where his upper legs and lower torso often start to itch when he runs, to the point of being extremely annoying and removing all pleasure form the activity.
If some doctor knows why this could be, please tell him!!!
The problem is a bit hard to reproduce however, and Ciro hasn't been able to determine which exact condition triggers it: temperature, nutrition, something else?
Ciro believes that this is not chiefly due to transpiration, but rather to the impact motion that running does on the muscles, as he has felt something similar on his arms some times while cycling in very rough terrain, which made his arms shake in a similar fashion. or for example if he has a water bottle on a tightly tied backpack that rubs his back, then the back itches at that point.
Also, running on a threadmill is not a problem at all. Ciro believes that this is because the threadmill is better amortized, and therefore does not cause the same mechanical stress required to create the itching as running on pavement.
Interestingly, Ciro didn't feel that at all when he played soccer enthusiastically as a child, and he was one of the fastest runners of the group for sure at that time. So he's not sure if it started when he got older, or if it is just because the difference in workloads between soccer and running.
youtu.be/PNgYW5N95z8?t=945 "My back itches" after riding on a bumpy makeshift motorcycle.
Hazard (computer architecture) Updated 2025-07-16
Ciro Santilli's undergrad studies at the University of São Paulo Updated 2025-07-16
Ciro's official diploma from the University of São Paulo read "Automation and Control Engineer at the Polytechnic School of the University of São Paulo".
The University of São Paulo had been elected the best South American university in the Times Ranking 2013 (archive) in all subjects.
Ciro finished the course with honors of "The Best Student in Automation and Control of the year 2013".
Ciro didn´t learn basically any control engineering however unfortunately. He did only the 3 base years of the electrical engineering course, and the rest got lost on stupid politics of having to go back to do 6 months from France to validate his Brazilian degree, see also: Section "Don't force international exchange students to come back early".
Ciro's call hierarchy notation Updated 2025-07-16
This is a simple hierarchical plaintext notation Ciro Santilli created to explain programs to himself.
It is usuall created by doing searches in an IDE, and then manually selecting the information of interest.
It attempts to capture intuitive information not only of the call graph itself, including callbacks, but of when things get called or not, by the addition of some context code.
For example, consider the following pseudocode:Supose that we are interested in determining what calls
f1() {
}
f2(i) {
if (i > 5) {
f1()
}
}
f3() {
f1()
f2_2()
}
f2_2() {
for (i = 0; i < 10; i++) {
f2(i)
}
}
main() {
f2_2()
f3()
}f1.Then a reasonable call hierarchy for
f1 would be:f2(i)
if (i > 5) {
f1()
f2_2()
for (i = 0; i < 10; i++) {
f2(i)
main
f3
f3()
main()Some general principles:
Classical limit Updated 2025-07-16
The idea tha taking the limit of the non-classical theories for certain parameters (relativity and quantum mechanics) should lead to the classical theory.
It appears that classical limit is only very strict for relativity. For quantum mechanics it is much more hand-wavy thing. See also: Subtle is the Lord by Abraham Pais (1982) page 55.
Classical mechanics Updated 2025-07-16
Classification of 4-transitive groups Updated 2025-07-16
en.wikipedia.org/w/index.php?title=Mathieu_group&oldid=1034060469#Multiply_transitive_groups is a nice characterization of 4 of the Mathieu groups.
Classification of finite fields Updated 2025-07-16
There's exactly one field per prime power, so all we need to specify a field is give its order, notated e.g. as .
It is interesting to compare this result philosophically with the classification of finite groups: fields are more constrained as they have to have two operations, and this leads to a much simpler classification!
Classification of finite groups Updated 2025-07-16
As shown in Video "Simple Groups - Abstract Algebra by Socratica (2018)", this can be split up into two steps:This split is sometimes called the "Jordan-Hölder program" in reference to the authors of the jordan-Holder Theorem.
Good lists to start playing with:
History: math.stackexchange.com/questions/1587387/historical-notes-on-the-jordan-h%C3%B6lder-program
It is generally believed that no such classification is possible in general beyond the simple groups.
Classification of regular polytopes Updated 2025-07-16
The 3D regular convex polyhedrons are super famous, have the name: Platonic solid, and have been known since antiquity. In particular, there are only 5 of them.
The counts per dimension are:
The cool thing is that the 3 that exist in 5+ dimensions are all of one of the three families:Then, the 2 3D missing ones have 4D analogues and the sixth one in 4D does not have a 3D analogue: the 24-cell. Yes, this is the kind of irregular stuff Ciro Santilli lives for.
Climate of the United Kingdom Updated 2025-07-16
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