I-micro:bit ifuna ukulinganiswa (calibration) ekuqaleni kwesifundo ngenxa yezizathu ezibini ezidityanisiweyo: idatha yokulinganisa i-magnetometer igcinwa kuphela kwimemori yexeshana (RAM), ecimekayo ngalo mzuzu ibhodi ikhutshwa kumbane, kwaye inkqubo yokusebenza imisa ngokuzenzekelayo ukusebenza kwekhowudi ukuze kuqhutywe inkqubo yokulinganisa xa ikhowudi yakho icela ulwalathiso lokuqala kwisivamvo (sensor) esingekalinganiswa. Kwimeko yaseklasini, oku kwenziwa mandundu yifenitshala: iidesika zesikolo ezenziwe ngesakhelo sentsimbi nezixhobo zekhompyutha ezikufuphi ziphazamisa ummandla wamagnetic wendawo, nto leyo eqinisekisa ukuba naluphi na ufundo olwenziwe ngaphandle kokulinganisa aluchanekanga kwaphela.

Kutheni Iidesika Zesikolo Ziphazamisa Ufundo Lwe-Magnetometer

I-micro:bit isebenzisa itshiphu edityanisiweyo ye-accelerometer kunye ne-magnetometer (njenge-LSM303 okanye i-FXOS8700 kwiibhodi ze-v1, okanye i-LSM303AGR kwi-v2). I-magnetometer ilinganisa amandla nolwalathiso lwemimandla yamagnetic kwiindawo ezintathu ezahlukeneyo. Kwibala lemidlalo elivulekileyo, owona mmandla uphambili ulinganiswayo ngumtsalane womhlaba (geomagnetic field, omalunga nama-30 ukuya kuma-60 e-microteslas).

Nangona kunjalo, kwigumbi lokufundela eliqhelekileyo eMzantsi Afrika, abafundi bahlala kwiidesika ezakhiwe ngentsimbi (mild tubular steel), amaxesha amaninzi ngaphezu kwemigangatho yekonkrithi eqinisiweyo equlethe intsimbi engaphakathi (rebar). Iilaptops ezikufuphi, iitshaja zezikrini, kunye neetroli zokutshaja zenza imimandla ye-electromagnetic esebenzayo. Oku kubangela iindidi ezimbini zokuphazamiseka kwemagnethi:

• Ukuphazamiseka kwentsimbi eqinileyo (Hard iron distortion): Iimagnethi ezisisigxina okanye izinto zentsimbi ezinemagnethi ezikufuphi zivelisa umahluko osisigxina osusa sonke isangqa semagnethi kwindawo yaso yokuqala (0, 0, 0).
• Ukuphazamiseka kwentsimbi ethambileyo (Soft iron distortion): Izinto ezinomtsalane wemagnethi (njengesakhelo sedesika yentsimbi) zigqwetha kwaye zicinezele imigca yommandla wemagnethi woMhlaba, zitshintshe oko bekufanele ukuba ngumlinganiselo osisangqa esigqibeleleyo ukuba sibe yimilo engalinganiyo (ellipsoid).

Xa i-micro:bit ivulwa ngokutsha, imathrikhi yayo yangaphakathi yokulinganisa iba yinto engenanto. Ngalo mzuzu umgca wekhowudi ucela compass heading okanye compass.heading(), inkqubo ye-micro:bit ihlola ukuba ingaba ikhona na imathrikhi yokulinganisa esebenzayo. Xa ingafumani nanye, iyayimisa ikhowudi yakho ize iqalise inkqubo enyanzeliswayo yokuthoba nokujika ibhodi (ukuzoba isangqa okanye ukugcwalisa izibane ze-LED ezingama-5x5) ukubala imbuyekezo yentsimbi eqinileyo nethambileyo.

Ingxaki Yokucima Nokuvula Amandla eKlasini

Kuba inkqubo eqhelekileyo igcina idatha yokulinganisa kwi-RAM kuphela, qho xa umfundi ekhupha i-micro:bit yakhe kwizibuko le-USB okanye ecima ibhetri, ulwazi lokulinganisa luyalahleka. Ukuba isifundo sakho siquka abafundi abangama-30 abatshintsha ikhowudi ngokuphindaphindiweyo, beyifaka ngetshiphu (flashing) nge-USB baze bayiqhube, ibhodi icima iphinde ivuleke kuko konke ukufakwa kwekhowudi. Oku kubangela ukulinganisa okufikelela kumashumi amathathu kumfundi ngamnye kwisithuba semizuzu engama-45 kuphela.

Okubi kakhulu, ukuba umfundi ugqiba ukulinganisa ngelixa ephehlelela i-micro:bit emoyeni kumphakamo wesifuba, aze abeke ibhodi phantsi kwiisentimitha ezi-5 kude nentsimbi yedesika, ummandla wamagnetic utshintsha kakhulu. I-micro:bit ayiqapheli ngokuzenzekelayo ukuba isiseko sitshintshile ngaphandle kokuba ifumane uphazamiseko olugqithisileyo, nto leyo ekhokelela kulwalathiso olungachanekanga okanye iinaliti zekhampasi ezingazinzanga.

Ukugqitha Nokulawula Ukulinganisa kwi-MakeCode

Kwi-Microsoft MakeCode, ibhloko ethi compass heading (°) iqulethe uhlolo olwakhelwe ngaphakathi: ukuba i-magnetometer ayikalinganiswa, ibiza i-input.calibrateCompass() ngokuzenzekelayo. Uneendlela ezintathu zokulawula le ndlela yokuziphatha kuxhomekeke kwiinjongo zakho zesifundo.

1. Ukuba ulwalathiso olungqalileyo ALUFUNEKI: Sebenzisa i-Accelerometer endaweni yoko

Ukuba ufundisa izinto ezisisiseko zokufaka idatha, ulawulo lokuthoba ibhodi, okanye ulwalathiso olulula (umz. ukuqhuba inqwelo-mafutha iye ngasekhohlo okanye ngasekunene), ngokuqinisekileyo awuyidingi i-magnetometer. Ootitshala badla ngokusebenzisa i-compass heading ngelixa eyona nto bayifunayo ikukuthoba (tilt/yaw). Ukusebenzisa i-rotation (pitch/roll) okanye i-acceleration kuyiphepha ngokupheleleyo inkqubo yekhampasi kwaye akubangeli sikrini sokulinganisa naphantsi kweziphi iimeko.

2. Linganisa kube kanye ngokucacileyo kwi-`on start`

Ukuba iprojekthi yakho iyayifuna ngokwenene ikhampasi (njengokukhangela indlela okanye i-orienteering), biza ukulinganisa ngokucacileyo ngaphakathi kwebhloko ethi on start kunokuba uyivumele ukuba izivelele ngesiquphe phakathi komsebenzi:

input.calibrateCompass()

Yalela abafundi ukuba baphakame, babambe i-micro:bit kude nemizimba yabo, baze bagqibezele inkqubo yokulinganisa emoyeni ngaphambi kokuba bahlale phantsi. Oku kuthintela umdlalo wokulinganisa ekuphazamiseni inkqubo ebalulekileyo yephrojekthi ngelixa kuvavanywa.

Ukulawula Ukulinganisa kwi-MicroPython

Kwi-MicroPython, unolawulo oluthe vetshe ngakumbi kwisivamvo. Ungahlola ubume bokulinganisa, ulinganise ngaphandle komdlalo wesikrini, okanye ufake amaxabiso okulinganisa ngqo kwikhowudi.

Ukuthintela isikrini sokulinganisa esithintela inkqubo

Ngokwendalo, ukubiza i-compass.heading() kwi-MicroPython kuza kuqalisa inkqubo yokulinganisa ukuba i-compass.is_calibrated() ibuyisa u-False. Ungakuthintela oku kuphazamiseka ngokuhlola ubume ngokucacileyo:

import compass

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

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

Ukufaka idatha yokulinganisa ngesandla

Ukuba abafundi bakho basebenza kwilabhoratri esisigxina kwaye ufuna ukuphelisa ngokupheleleyo umdlalo wokulinganisa ngexesha lokubhala ikhowudi, unokufumana amanani okulinganisa kube kanye, uwabhale kwindawo yokugcina engacimekiyo (i-micro:bit internal flash file system), kwaye uwalayishe xa ibhodi ivulwa. I-MicroPython inika ufikelelo olunzulu nge-compass.get_field_strength() kunye neendlela zokumisa ukulinganisa ukuseta amaxabiso ngokuthe ngqo, itshaye ngaphandle inkqubo yokujika ibhodi ngokupheleleyo.

Inkqubo Efanelekileyo Yaseklasini

Ukugcina iklasi yerobhothiki okanye yekhowudi iqhuba kakuhle ngaphandle kokulahlekelwa yimizuzu elishumi ngenxa yokujikajika kweebhodi:

• Gcina iibhodi kude nezakhelo zeedesika: Gcina umgama omalunga ne-15 ukuya kuma-20 cm phakathi kwe-micro:bit kunye nayo nayiphi na imilenze yentsimbi, izinto ezixhonywe edesikeni, okanye iziseko zezikrini zekhompyutha.
• Musa ukulinganisela phezu kwetafile: Ukuba i-micro:bit ilinganiswa ngelixa ilele kwidesika yentsimbi, ilinganisa ngokuhambelana nokuphazamiseka kwaleyo desika. Ngalo mzuzu umfundi ayiphakamisayo ukuze ahambe nayo, ulwalathiso luza kuphosisa. Soloko ulinganisela kumphakamo wesinqe okanye wesifuba emoyeni ovulekileyo.
• Hlola ukuba uyamfuna ngokwenene uMntla ochanekileyo: Kwi-80% yemingeni yokufundisa esisiseko—njengokulandela umgca, ukunqanda imiqobo, okanye imidlalo elawulwa kukuthoba ibhodi—i-magnetometer asisosivamvo esifanelekileyo. Sebenzisa i-accelerometer endaweni yoko.

Ukufumana iimodyuli zerobhothiki ezicwangcisiweyo, uyilo lwezixhobo, kunye nezixhobo zezifundo ezilungiselelwe iimeko zamagumbi okufundela aseMzantsi Afrika, jonga izikhokelo zokufundisa kwi-Sheen Canvas okanye uphonononge iindibano zethu zocweyo zophuhliso lobuchwepheshe kwi-Sheen Academy.