I-micro:bit idinga ukulinganiselwa ekuqaleni kwesifundo ngenxa yezizathu ezimbili ezihlangene: idatha yokulinganisela ye-magnetometer igcinwa kuphela kwimemori yesikhashana (RAM), ecimeka ngaso leso sikhathi lapho ibhodi linqunywa khona ugesi, kanti futhi uhlelo lwesistimu (runtime) lumisa ngokuzenzakalelayo ukusebenza kwekhodi ukuze luqhube inqubo yokulinganisela ngesikhathi sokuqala lapho ikhodi yakho icela indlela eya kuyo (heading) kusuka kusensoli engalinganiselwe. Esimweni sasekilasini, lokhu kwenziwa kube kubi kakhulu yifenisha yasekilasini: amadeski ajwayelekile anohlaka lwensimbi kanye nemishini yamakhompyutha eseduze kuphazamisa amandla kazibuthe womhlaba endawo, okuqinisekisa ukuthi noma yikuphi ukufunda okungalinganiselwe kuba namaphutha amakhulu kakhulu.

Kungani Amadeski Esikole Ephazamisa Ukufundwa Kwe-Magnetometer

I-micro:bit isebenzisa itshisi (chip) ehlanganisa i-accelerometer ne-magnetometer (njenge-LSM303 noma i-FXOS8700 kumabhodi e-v1, noma i-LSM303AGR ku-v2). I-magnetometer ikala amandla nesiqondiso samandla kazibuthe emigqeni emithathu eqondene ngqo (orthogonal axes). Enkundleni yezemidlalo evulekile, amandla amakhulu akalwayo ngamandla kazibuthe oMhlaba (cishe ama-microtesla angama-30 kuya kwangama-60).

Nokho, ekilasini elijwayelekile laseNingizimu Afrika, abafundi bahlala emadeskini akhiwe ngensimbi elula engamashubhu (mild tubular steel), kaningi ngqo phezu kwezitezi zikakhonkolo eziqiniswe ngamapulangwe nensimbi (steel rebar). Ama-laptop aseduze, amapulaki kagesi amamonitha (power bricks), nezinqola zokushaja amadivayisi kwakha amandla kagesi kazibuthe (electromagnetic fields) asebenzayo. Lokhu kudala izinhlobo ezimbili zokuphazamiseka kukazibuthe:

• Ukuphazamiseka kwensimbi eqinile (Hard iron distortion): Ozibuthe bangempela noma izinto zensimbi ezikazibuthe eziseduze zikhiqiza ukuchezuka okungaguquki okususa yonke indilinga kazibuthe kude nomsuka (0, 0, 0).
• Ukuphazamiseka kwensimbi ethambile (Soft iron distortion): Izinto ezinobuzibuthe bensimbi (njengohlaka lwedeski lensimbi elula) zigoba futhi zicindezele imigqa yamandla kazibuthe woMhlaba, ziguqule lokho okufanele kube isilinganiso esiyindilinga ephelele sibe isimo se-ellipsoid esingalingani.

Lapho i-micro:bit iqala ukusebenza kabusha, i-matrix yayo yokulinganisela yangaphakathi isuke ingenalutho. Ngokushesha nje lapho umugqa wekhodi ucela compass heading noma compass.heading(), i-runtime ye-micro:bit ihlola ukuthi ingabe ikhona yini i-matrix yokulinganisela esemthethweni. Uma ingatholi lutho, imisa isikripthi sakho bese iqala inqubo ephoqelekile yokutshekisa ibhodi (ukudweba indilinga noma ukugcwalisa i-matrix ye-LED engu-5x5) ukuze ibale izibalo zokunxephezela ukuphazamiseka kwensimbi eqinile nethambile.

Inkinga Yokucima Nokuvala Amandla Kagesi Ekilasini

Ngenxa yokuthi i-runtime ezenzakalelayo igcina idatha yokulinganisela ku-RAM kuphela, ngaso sonke isikhathi umfundi lapho ekhipha i-micro:bit yakhe embobeni ye-USB noma ecima iphakethe lamabhethri, lezo zibalo zokunxephezela ziyanyamalala. Uma isifundo sakho sihlanganisa abafundi abangama-30 abalokhu behlela ikhodi ngokuphindaphindiwe, beyifaka ngebhodi nge-USB (flashing), futhi beyiqhuba, ibhodi liqala phansi amandla kagesi kukho konke ukufakwa kwekhodi. Lokho kubangela ukulandelana kokulinganisela okungafika kumashumi amathathu kumfundi ngamunye esikhathini esisodwa semizuzu engama-45.

Okubi nakakhulu, uma umfundi eqeda ukulinganisela ngenkathi enyakazisa i-micro:bit emoyeni ebangeni lesifuba sakhe, bese ebeka ibhodi phansi amasentimitha angama-5 ukusuka kuhlaka lwensimbi lwedeski, amandla kazibuthe ashintsha kakhulu. I-micro:bit ayiqapheli ngokuzenzakalelayo ukuthi isisekelo sesishintshile ngaphandle kokuthi i-runtime ibone i-vector yamandla engavumelekile ngokuphelele, okuholela eziqondisweni ezingalungile noma enalithini yekhampasi elokhu linxaxha.

Ukugwema Nokulawula Ukulinganisela ku-MakeCode

Ku-Microsoft MakeCode, ibhulokhi elithi compass heading (°) liqukethe ukuhlola okwakhelwe ngaphakathi: uma i-magnetometer ingalinganiselwe, libiza ngokuzenzakalelayo elithi input.calibrateCompass(). Unezindlela ezintathu zokulawula lokhu kuziphatha kuye ngezinhloso zesifundo sakho.

1. Uma isiqondiso esiqondile SINGADINGEKI: Sebenzisa i-Accelerometer esikhundleni sayo

Uma ufundisa okokufaka okuyisisekelo, izilawuli zokutshekisa, noma isiqondiso esilula (isb. ukuqondisa inqola kwesobunxele noma kwesokudla), cishe awuyidingi nhlobo i-magnetometer. Othisha bavame ukusebenzisa compass heading lapho empeleni befuna ukutshekisa (tilt) noma ukuzungezisa (yaw). Ukusebenzisa rotation (pitch/roll) noma acceleration kugwema ngokuphelele isistimu yekhampasi futhi akukaze kuqalise isikrini sokulinganisela.

2. Linganisela kanye ngokusobala ku-`on start`

Uma iphrojekthi yakho idinga ngempela ikhampasi (njengokuthola indlela noma ukuzula), biza ukulinganisela ngokusobala ngaphakathi kwebhulokhi elithi on start esikhundleni sokukuvumela ukuthi kuqale kungalindelekile phakathi ne-loop:

input.calibrateCompass()

Yala abafundi ukuthi basukume, babambe i-micro:bit kude nemizimba yabo, bese beqeda inqubo yokutshekisa emoyeni ovulekile ngaphambi kokuhlala phansi. Lokhu kuvimbela umdlalo wokulinganisela ukuthi ungaphazamisi i-loop eyinhloko yomqondo wekhodi ngenkathi behlola.

Ukulawula Ukulinganisela ku-MicroPython

Ku-MicroPython, unokulawula okunembile kakhulu phezu komjikelezo wempilo wensensoli. Ungahlola isimo sokulinganisela, ulinganisele ngaphandle kokusebenzisana nomsebenzisi, noma ufake amanani wokunxephezela abhaliwe ngqo ekhodini.

Ukuvimbela isikrini sokulinganisela esimisa ukusebenza

Ngokuzenzakalelayo, ukubiza compass.heading() ku-MicroPython kuzovusa inqubo yokulinganisela uma compass.is_calibrated() ibuyisa u-False. Ungakugwema ukumiswa okungalindelekile ngokuhlola isimo ngokusobala:

import compass

if not compass.is_calibrated():
    compass.calibrate()

while True:
    heading = compass.heading()
    # Project logic here

Ukufaka idatha yokulinganisela ngesandla

Uma abafundi bakho besebenza endaweni yelebhu engagudlukiyo futhi ufuna ukuqeda ngokuphelele umdlalo wokutshekisa ngesikhathi sokubhala ikhodi okuphindaphindwayo, unganquma amanani wokunxephezela wesisekelo kanye, uwabhale kwisitoreji esingacimeki (uhlelo lwefayela lwe-flash lwangaphakathi lwe-micro:bit), bese uwafaka lapho ibhodi liqala ukusebenza. I-MicroPython inikeza ukufinyelela kwamazinga aphansi nge-compass.get_field_strength() kanye nezindlela zokumisa ukulinganisela ukusetha amanani wokunxephezela ngqo, yeqe ngokuphelele ukulandelana kokutshekisa.

Inqubo Esebenzayo Yasekilasini

Ukuze ugcine ikilasi lerobhothiki noma lokubhala amakhodi liqhubeka kahle ngaphandle kokulahlekelwa yimizuzu eyishumi ngokutshekisa amabhodi:

• Gcina amabhodi kude nozimele bamadeski: Gcina okungenani ibanga elingu-15 kuya ku-20 cm phakathi kwe-micro:bit nanoma yimiphi imilenze yesakhiwo sensimbi, izinsimbi zedeski, noma izisekelo zamamonitha.
• Ungalinganiseli ibhodi lilele phezu kwetafula: Uma i-micro:bit ilinganiswa ngenkathi ilele phezu kwedeski lensimbi, ilinganiselwa ekuphazamisekeni kukazibuthe kwalelo deski. Ngesikhathi umfundi eyiphakamisa ukuze ahambahambe, isiqondiso sizobe singalungile. Hlala ulinganisela ebangeni lokhalo noma lesifuba emoyeni ovulekile.
• Hlola ukuthi ingabe uyayidinga ngempela iNyakatho eqondile: Ezinseleleni zekilasi eziyisisekelo ezingama-80%—njengokulandela umugqa, ukugwema izithiyo, noma imidlalo elawulwa ngokutshekisa—i-magnetometer akuyona insensoli efanele. Sebenzisa i-inertial measurement unit (i-accelerometer) esikhundleni sayo.

Ukuthola amamojula ahlelekile erobhothiki, imidwebo yereferensi yehadiwe, namakhithi ezifundo alungiselelwe izimo zamakilasi aseNingizimu Afrika, hlola imihlahlandlela yokufundisa ku-Sheen Canvas noma ubuyekeze imihlangano yethu yokuthuthukisa amakhono obuchwepheshe ku-Sheen Academy.