With pre-soldered male pin headers.
>>> machine.unique_id()
b'\xe6ad\x08C8%$'
As of 2018-12, I believe that I might have fried the UART on this board when I burnt my last UART to USB converter by connecting ground to 5V.
Linux kernel logs don't show, but do show with the exact same components on the Pi 3 (SD card with enable_uart=1 + image Raspbian Lite 2018-11-03 and UART cables).
Serial from cat /proc/cpuinfo: 00000000a50c1f69
Datasheets: Raspberry Pi 2.
Linux on SSH and bare metal blinker both work on this board, so the rest of the board seems alive.
Serial from cat /proc/cpuinfo: 00000000c77ddb77
Datasheets: Raspberry Pi 3.
2021-08 bedroom battery out, 7.29V out of 9V duracell duralock. Buying pack of 12 Energizer nine-volt batteries. Measurement on new battery: 9.68V.
2019-12-26: applied Ronseal mould killer on external north east living room walls, had widespread light brown mould spots, and more localized black mould spots. The water insulation here is bad, possibly due to being on the last floor. Also applied next to window sills on those walls.
2021-01: kitchen extractor right lamp burnt. Replaced with another Eveready.
2021-01: left back bulb burnt, put in another LE GU10 LED Bulbs
2020-11: kitchen extractor left lamp burnt again. Did I forget to report a right side burn earlier, or is there something wrong with the left one? Also can't find the second bulb that was likely bought last time, so likely the right one burnt and the other bulb was used for it. Buying www.amazon.co.uk/dp/B00LOBUDSS "4 x Eveready 20 W 12 V G4 Dimmable Halogen Capsule Light Bulbs Pack of 4" for 3.66 pounds. Worked, felt a bit more yellow than the previous one. Packet documents 2000 hours, 2800K color, 8000+ switches.
2020-08: kitchen right back had been out for a while, bought: www.amazon.co.uk/dp/B00LN0RPA4 LE GU10 LED Bulbs, Warm White 2700K, 50W Halogen Lamp Equivalent, 4W 350lm, 120° Wide Beam Angle, Recessed or Track Light Bulb, Pack of 5 (Energy Class A++), 5 for 10 pounds.
2019-11: front right kitchen lamp burnt, Sylvania GU10 50W. 50W was likely some useless "incandescent equivalent" measure. Replaced: GE LED 5W 345 lumens 2700K Warm 15k hours, which looks exactly the same.
2019-05: kitchen extractor left lamp burnt. Was: DURA G4 12V20W: www.amazon.co.uk/Halogen-Light-Bulbs-Lamps-5watt/dp/B003IVP12A Replaced: Sainsbury's halogen G4 20W12V.
When I came, two Bell GU4 (MR11) 20W 12v.
One burnt. Put in an ASDA halogen one.
ASDA burnt, put in TopLux on right, old Bell left.
2019-01-24, right one burnt a few days ago, old Bell still works. Inner part black, and black dot on the wire. Putting new TopLux again, but this time on the left, old bell on right.
2019-01-24 toilet top lamp also burnt a few days ago, but not at the same time as mirror. Diall, 240V 40W, GU10. Putting in IKEA 240V 35W.
2019-02-02 toilet mirror lamp left (TopLux) burnt. Don't know what to do anymore. Only the magic Bell lamp works.
2019-03-06 toilet top lamp left burnt, IKEA 240V 35W GU10. Putting in another one.
2019-03-28 toilet top lamp right burnt, IKEA 240V 35W GU10. Waiting for people to come to look at transformer, there is definitely something wrong.
2019-04-03 top lamps: replaced with LED (LAP GU10 3W) since lower power, transformer not changed. Mirror lamps: transformer changed, left one replaced with Homebase Halogen 20W 12V. When I came back lamps flickering badly and sometimes not turning on, recalled technician.
2019-04-12 mirror lamp: it was just he connector that was bad, it was changed, also put LEDs there to make it less warm and hopefully have less tear on connector.
  • Elegoo Breadboard power supply module MB‐V2:
    • Input voltage: 6.5-9v (DC) via 5.5mm x 2.1mm plug
    • Output voltage: 3.3V/5v
    • Maximum output current: 700 mA
    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: 1.8m
    Parts list from the ZIP:
  • resistors:
    • 10x each:
    • 30x 220
  • 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:
    • White LED 10x
    • Kingbright RGB LEDs 10x red, green, yellow, blue:
      • maximum Continuous Forward Current: 30 mA for read and blue, 25 mA for green
      • 303025
      • under 20 mA
      20 mA appears to be the typical operation. So with the 2.0 V drop on 5 V power we want a resistor such that:
      for the max 50 mA we would instead have 60 Ohms
Home 2017 TalkTalk 38Mbps nominal, Google M-lab speed test:
Home 2025 Giffgaff
Home 2025 Sky Broadband WiFi Max Hub SR213 (SR213-02-UK-wht) 1GBPS:
Admin at 192.168.0.1/:

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact