Et lidt underligt spørgsmål måske, men er der nogen der har gjort sig erfaringer med Micro:bit i frostvejr – Er den stabil, og kan den starte op i f.eks. -20 grader ? Jeg har googlet – men søgeresultatet på de relevante søgning er temmelig forurenet af at der jo er en indbygget temperatursensor…

Ja, det ser da lidt underligt ud. Der er ikke opgivet nogen driftstemperatur (“oprarating temperature”) eller for så vidt opbevaringstemperatur (“storage temperature”) i specifikationerne for hverken V1.5 (https://tech.microbit.org/hardware/1-5-revision/) eller V2 (https://tech.microbit.org/hardware/). En søgning i dokumentationens git-arkiv bekræfter at der kun nævnes noget om temperaturer når den indbyggede sensor i nRF-SoC’en omtales (https://github.com/microbit-foundation/dev-docs/search?q=temperature+&type=). Ligeledes bruges ordet “operating” kun om spænding, strøm og system (=OS) (https://github.com/microbit-foundation/dev-docs/search?q=operating&type=). Så den oplysning er Micro:bit Foundation åbenbart ikke særligt vilde med at dele, hvilket tyder på at det ikke har været en prioritet under design og produktion (hvilket er forståeligt nok for et ikke-industrielt stykke undervisningsmateriale). Så du skal nok under alle omstændigheder ikke forvente en konsistent oplevelse. Hvis man skulle give et kvalificeret bud, kunne man kigger på hovedkomponenternes specificerede driftstemperaturer, hvilket i hvert fald siger noget om de øvre og nedre grænser, men komponenternes komplekse interaktioner med hinanden (mekanisk, termisk, elektrisk) i det færdige produkt har selvfølgelig betydning for de endelige grænser. V1.5:

• nRF51822 (primær SoC): -25 – 75 grader C (http://infocenter.nordicsemi.com/pdf/nRF51822_PS_v3.1.pdf#page=38)
• KL26 (USB-interfacechip): -40 – 105 grader C: (http://www.nxp.com/docs/pcn_attachments/16440_KL26P64M48SF5_Rev.4.pdf)

V2:

• nRF52833 (primær SoC): -40 – 85 grader C (kan gå op til 105 grader C under specielle betingelser) (https://infocenter.nordicsemi.com/pdf/nRF52833_PS_v1.3.pdf#page=608)
• KL27 (USB-interfacechip): -40 – 105 grader C (https://www.nxp.com/docs/en/data-sheet/KL27P64M48SF6.pdf)

Det giver da et fingerpeg, god fornøjelse med fryseren ;).

Lidt flere dråber i Spørgsmål&Svar-kategorien fra Facebook.

Når jeg endelig forvilder mig derind, og går på opdagelse i de tekniske grupper, ender det ofte med at får jeg skrevet en fristil i forsøget på at hjælpe.

Denne gang en snak om Android på “PC”, og basale digitale processeringsbehov for den almindelige dansker.

Spørgsmål

Stillet i gruppen “Danske Android Brugere “:

Er der nogen som ved, om man kan få en pc med Android system?

Svar

Mit svar:

Som andre omtaler, kan der fås en uofficiel variant af det frie styresystem Android til x86-arkitekturen (den gængse Intel/AMD-baserede computer kendt som “personlig computer”).

Det projekt lever på https://www.android-x86.org/. Installationsvejledning på engelsk er på https://www.android-x86.org/installhowto.html. Man kan både installere som multiboot på samme disk som et eksisterende operativsystem, starte fra en ekstern disk (USB-medie, cd/dvdrom e.l.) eller evt. køre i en virtuel maskine på et eksisterende operativsystem (VirtualBox,QEMU/KVM, VMware Player/Workstation).

Jeg har kun erfaring med livedisk boot fra USB og VM, og der synes jeg ikke altid tingene spiller perfekt, så forvent ikke en helt problemfri oplevelse.

“Android på PC” er på kanten af noget understøttet, hvor man ofte er på egen hånd. Nogle af folkene bag Andoid-x86 forsøgte at lave en kommerciel forretning på det, hvor det var tanken at sælge det som færdige hardwareenheder, RemixOS – https://en.wikipedia.org/wiki/Remix_OS, men det gik ikke så godt og er lukket ned igen.

Hvis behovet bare er “en bærbar computer uden for meget vrøvl”, så er en færdig Chromebook med Chrome OS (der ligesom Android også er bygget på GNU/Linux) eller noget af det der dyre Frugt-udstyr nok det mest tilgængelige (men jeg fornemmer at pris også kunne være en faktor?). Til forskel fra traditionelle operativsystemer til computere, er Chrome OS dog møntet specifikt på at få dig til at bruge Googles webbaserede tjenester (mere om softwaren bag på https://www.chromium.org/chromium-os), så hverken software eller hardware er beregnet til at lagre data på selve enheden, og der er sjældent meget diskplads tilgængelig til f.eks. billeder.

Et hurtigt kig på markedet identificerer Acer Chromebook 15 (https://www.edbpriser.dk/produkt/acer-chromebook-15-cb515-1h-c7kg/) og Lenovo S330 (https://www.edbpriser.dk/produkt/lenovo-chromebook-s330-81jw-3292492/) som populære Chromebook i 2k kr.-klassen, men kender ikke maskinerne specifikt.

God jagt :).

The support request replicated below was posted as ticket #20427 on Micro:bit support on 2019-01-31 22:19 CET spawned by discussion in F-Droid RFP #662 about inclusion of the official Micro:bit Android Companion application in the free software application store F-Droid.

Hi at Micro:bit Educational Foundation.

We are wondering a bit in the F-Droid free software community (https://gitlab.com/fdroid/rfp/issues/662) whether it is worthwhile for us to try to loosen the official Android companion application (https://microbit.org/guide/mobile/#og-app) from its non-free dependencies to make it available in the free software application store F-Droid (https://f-droid.org/).

This leads to a couple of questions you can hopefully help answering;

1) Do you regard the application as alive and supported?

The latest release of the application was v2.0 2017-01-17 (https://play.google.com/store/apps/details?id=com.samsung.microbit) and the publicly available code base (https://github.com/Samsung/microbit/) seems to have been completely abandoned. Only two commits were ever made by Samsung and no involvement with the community has been seen at all.

2) How come the big difference in maturity between the iOS and Android mobile applications?

It seems like the iOS application has received some more attention seeing regular updates through to v3.0.2 released 2018-11-01 (https://itunes.apple.com/gb/app/micro-bit/id1092687276?mt=8). Also it appears to have a much wider fetaureset (https://play.google.com/store/apps/details?id=com.samsung.microbit&reviewId=gp%3AAOqpTOGpgo4CF2qrry4qWqLXyj0TZaEEJcrTB-yZ61o4nJbqhq-2mBojlYQJP7BzdkAzseGaLD1sVO9fBv1R3sY) developed along the way by Insight Resources (http://www.insightresources.co.uk/microbit/index.html).

The Android application appears to have been more of a one-off project from Samsung having all sorts of issues especially with Bluetooth that has never been attended to (http://www.suppertime.co.uk/blogmywiki/2016/04/mobile-microbit/, https://support.microbit.org/support/solutions/articles/19000041104-diagnosing-bluetooth-problems-android).

3) Is there a plan to bring the application in better shape?

Some activity can be seen in repository forks and branches from the original Samsung committer ailrohit (https://github.com/Samsung/microbit/compare/master…ailrohit:school_project) and microbit-sam (https://github.com/Samsung/microbit/compare/master…microbit-sam:partial-flash) identifying as being from the foundation but none of this work seem to be included in releases yet.

4) If a freed fork is made for inclusion in F-Droid would you be willing and able to integrate the changes into the official sources?

F-Droid prefers an upstream source which can be directly built without non-free dependencies using an appropriate set of build options. This greatly simplifies maintenance and build efforts. A forked repository is already in place at the foundation’s Github organization (https://github.com/microbit-foundation/microbit-android) but is at the moment even with the stale Samsung repository.

Thanks for any clarifications you can provide.

Regards,
Mikkel

Having used the Arduino prototyping platform (a loose combination of specific pieces of somewhat open/free hardware and a more open/free software stack) for some time for educational and tinkering purposes in my local hackerspace (geeklabs.dk) I have seen and studied the Arduino UNO hardware and lots of its “clones/compatibles/knockoffs” and their common MCU (MicroController Unit);

Atmel ATmega328P

I had begun wondering what the P in the microcontroller model name actually meant. So here is an attempt to decode the Atmel megaAVR chip numbering system. The other existing AVR based series UC3, tinyAVR, XMEGA, Battery & Automotive, will probably employ similar naming schemes.

The remainder of the product name following “ATmega” expresses the available flash memory and the approximate pin count of the package in an integer and optionally other features as either integer or letter (like the initial wondering of P in 328P above).

Starting with the integer, it is a concatenation of two separate integers encoding the flash size and pin count as defined below. The division of the two is non-ambiguous leaving some interpretation to be done.

1st integer: onboard flash size
8 = 4 KiB
8 = 8 KiB
16 = 16 KiB
32 = 32 KiB
64 = 64 KiB
128 = 128 KiB
256 = 256 KiB

2nd integer: total pin number
(none) = standard pin count (differs)
8=28/32-pin
4= 40/44/49-pin
5= 64-pin
0= 100-pin

Suffix (char or integer), multiple possible
P = picoPower (max. consumption 9mA@8MHz,5v vs. 12mA@8Mhz,5v for non-P)
9=LCD controller
U2 = USB controller
U4 = USB controller
A  = ?

Exceptions
Note that some of the product names are completely void of these rules. Others employ different numbering but still with a familiarity to the above.

An example:
ATmega6490A: 64KB flash, 100-pin, LCD Controller

Sources

• http://www.atmel.com/products/microcontrollers/avr/megaavr.aspx
• http://www.atmel.com/products/microcontrollers/avr/