Kutheni Isikhululo Sezulu Sasesikolweni Sakho Sihlala Sibambelele kwi-99% Yokufuma
Iziva-kufuma ezikwinqanaba lokuqala ziyama ngaphandle kuba umbethe ugcwalisa indawo yazo yokulinganisa kwaye ubambisa izinto ezingcolisayo eziqhuba umbane. Ukulungisa oku kufuna ubume benzwa obufanelekileyo, ukungenisa komoya okungangenisi manzi, kunye nokuhamba komoya owaneleyo.
Ukuba isikhululo sezulu sesikolo sakho besisebenza ngokuthembekileyo kwikota yaso yokuqala kwaye ngoku sinika ingxelo ye-99% okanye i-100% yokufuma (relative humidity) yonke imihla kungakhathaliseki ukuba injani imozulu, inzwa yakho ifumene ukulahleka kokuchana ngenxa yokugcwala kwamanzi (saturation drift) kunye nongcoliseko lomphezulu. Le yeyona ndlela ixhaphakileyo yokonakala kwezikhululo zezulu zemfundo ze-IoT, kwaye phantse ngamaxesha onke kudalwa kukusebenzisa iinzwa ezenzelwe ngaphakathi endlwini ngaphandle kolawulo olwaneleyo lokujiya komphunga.
Ifiziksi yokubambelela kwi-99%
Uninzi lweeprojekthi zerobhothiki zezikolo ezikwinqanaba lokuqala ziqala ngeenzwa ezisisiseko ezifana ne-DHT11 eluhlaza okwesibhakabhaka okanye i-DHT22 emhlophe (AM2302). Ezi yunithi zilinganisa ukufuma zisebenzisa i-polymer substrate eguqula ukuxhathisa (resistive) okanye ifilimu evulekileyo ye-capacitive. Njengoko ukufuma okusingqongileyo kusenyuka, i-polymer ifunxa umphunga wamanzi, iguqule ukuhamba kombane (electrical impedance), nto leyo i-microcontroller yangaphakathi eyiguqulela kufundo lwepesenti.
Ezi nzwa zenzelwe izixhobo zangaphakathi ezifana nezinto zokupholisa umoya (air conditioners), ii-incubator, kunye nezifumisi zasendlwini. Kwindawo engaphandle, ngakumbi ngexesha lentsasa zasebusika eMzantsi Afrika eNtshona Koloni okanye kubusuku obupholileyo kakhulu e-Highveld, iqondo lobushushu rhoqo lihla lifikelele kwinqanaba lokujiya komphunga (dew point). Umphunga wamanzi ujika ube ngumbethe ongamanzi ngqo phezu kwenzwa ebekwe esichengeni.
Xa amanzi athe ngqo ejiya kwisiseko senzwa esisisiseko, kwenzeka izinto ezintathu:
- Ukubanjiswa kwiinqweme ezincinci (Capillary entrapment): Amanzi angcolileyo abanjiswa ngaphakathi kumaleko wokulinganisa oneentunja. Nangona umphunga wamanzi unokuphuma ngokukhawuleza xa amaqondo obushushu esenyuka, amathontsi amanzi aphuma kancinci, ngakumbi xa evalelwe ngaphakathi kwibhokisi yeplastiki engenabushushu.
- Ungcoliseko lwee-ion (Ionic contamination): Uthuli olusemoyeni, umgubo weentyantyambo, kunye netyuwa epephuka elwandle ziyanyibilika kumaleko wamathontsi aphezu kwenzwa. Xa amanzi egqibela ngokutshisa, ashiya iintsalela zeminerali ezincinci eziqhuba umbane. Ezi zenza ibhulorho phakathi kwee-electrode zokulinganisa, nto leyo ehlisa ukumelana nombane ngokusisigxina ize ibambelele ifundo kufuphi nelona nqanaba liphezulu.
- Ukonakala kwesiseko senzwa (Substrate degradation): Ukugcwala kwamanzi ixesha elide kubangela ukuba i-polymer efunxa ukufuma idumbe ngaphaya komlinganiselo wayo wokwelula, itshintshe ngokupheleleyo ulungelelwaniso lwayo lokuqala (baseline calibration).
Umgibe webhokisi yokukhusela: Ukukhusela emvuleni xa kuthelekiswa nokungena komoya
Xa iqela lesikolo lifumanisa ukuba imozulu yonakalisa izixhobo zabo, into eziqhelekileyo abayenzayo kukuvala ibhokisi ngokuqinileyo ngakumbi. Ootitshala nabafundi badla ngokufaka ii-microcontroller kunye neenzwa ngaphakathi kwiibhokisi ezikhuselweyo emanzini (junction boxes) okanye kwizikhongozeli ezishicilelwe nge-3D ezinemingxuma emincinci kuphela emazantsi.
Oku kudala imozulu encinci yangaphakathi ekhawulezisa ukufa kwenzwa. Ngethuba leemva kwemini ezinelanga, umoya wangaphakathi uyanda uze uphumele ngaphandle. Njengoko amaqondo obushushu esihla ebusuku, ibhokisi itsala umoya obandayo nofumileyo. Umbethe uyajiya ngaphakathi ebhokisini phezu kweplastiki ebandayo nakwiibhodi zesekethe, kodwa ngenxa yokuba kungekho moya unqumlayo, olo kufuma alukwazi ukuphuma xa ilanga liphuma. Inzwa ihlala kwindawo efudumeleyo, emileyo nefana ne-terrarium ekwi-100% yokufuma.
Iinzwa zezulu zangaphandle akufuneki zivalelwe kwibhokisi engenamoya. Zifuna isikhuseli semitha yelanga esineepaneli ezinemivalo (mini Stevenson screen). Isikhuseli semitha yelanga esifanelekileyo sinika imisebenzi emithathu engenakuthethwa-thethwa:
- Sinqanda imitha yelanga ethe ngqo, sithintele ukufudumala kwelanga ekugqwutheni izibalo zeqondo lobushushu kunye nokufuma (relative humidity).
- Siphambukisa imvula ehla ngqo nethwalwa ngumoya kude kwizinto zombane.
- Sivumela ukuhamba komoya okuqhubekayo, okusingqongileyo phezu kwenzwa ukuze umoya olinganiswayo ube ngumela ngokwenene umoya ojikelezileyo.
Isisombululo: Iinzwa ze-capacitive I2C ezinokuzivuselela
Ukwakha isikhululo sezulu sangaphandle esihlala iminyaka emininzi yezifundo ngaphandle kokulahleka kokuchana, suka kwiinzwa zocingo olunye (single-wire) zabaqalayo uye kwiinzwa ezisemgangathweni wemizi-mveliso ezisebenza nge-I2C bus, ezifana ne-Sensirion SHT3x series (SHT30, SHT31, SHT35) okanye i-Bosch BME280.
| Uphawu | Inqanaba Lokuqala (DHT11 / DHT22) | Ezilungele Ngaphandle (SHT31 / BME280) |
|---|---|---|
| Indlela Yokulinganisa | I-resistive polymer / i-capacitive evulekileyo | Ifilimu ye-planar capacitive echanekileyo |
| Ujongano (Interface) | Ucingo olunye olulodwa (luva ixesha kakhulu) | I-I2C bus esemgangathweni |
| Ukuvuselela Emva Kokujika Kwamanzi | Akukho (kufuneka yomiswe ngesandla) | Isifudumezi esidityanisiweyo esicwangciswayo |
| Isihluzo Esikhuselayo | Igrili yeplastiki enemithobo | I-PTFE hydrophobic membrane ekhethekayo |
| Ubude Bokuphila Ngaphandle | Iinyanga ezi-1–4 ngaphambi kokulahleka kokuchana | Iinyanga ezingama-24+ kwisikrini esinemivalo |
Iinzwa zale mihla ze-capacitive I2C zisombulula ingxaki yokugcwala kwamanzi ngeempawu ezimbini eziphambili zobunjineli:
1. Iikepusi zokuhluza ze-PTFE ezingangenisi manzi (Hydrophobic)
Iinzwa ezifakwe i-PTFE (polytetrafluoroethylene) membrane enemithunzi emincinci zivumela iimolekyuli zomphunga wamanzi ukuba zidlule ngokukhululekileyo ngelixa zithintela amathontsi amanzi, uthuli, kunye netyuwa yaselwandle ukuba zingachukumisi icandelo elilinganisayo. Nokuba kungexesha lemvula ebhudlayo okanye inkungu engqingqwa yasekuseni, amanzi awanakufikelela kumaleko we-polymer osebenzayo.
2. Izifudumezi zokuxilonga ezikwitshiphu (On-chip diagnostic heaters)
Iinzwa ezifana ne-SHT31 ziquka isifudumezi esakhelwe ngaphakathi esinokuvulwa kwaye sicinywe kusetyenziswa isoftware nge-I2C bus. Ukuba i-microcontroller yakho ifumanisa ufundo olungaphezulu kwe-95% ixesha elide ngaseluvuleni, inokuvula isifudumezi sangaphakathi kangangemizuzwana emi-5 ukuya kweli-10. Oku kunyusa kancinci iqondo lobushushu betshiphu ibe ngaphezulwana kwemozulu engqongileyo, sitshise amathontsi amancinci omphunga ngaphambi kokuthatha umlinganiselo.
Uluhlu lwamanyathelo ama-4 okulungisa isikhululo sakho sasesikolweni
- Yeka ukusebenzisa uthotho lwe-DHT: Faka endaweni yeemodyuli ze-DHT11 ne-DHT22 imodyuli ye-BME280 efakwe i-conformal coating okanye i-SHT31 enekepusi yokuhluza. Ukufumana iikiti zokujonga imozulu nokusingqongileyo zaseklasini ezilungiselelwe ukumelana neemeko zangaphandle, jonga iindlela ezikhoyo zokumisa izixhobo kwi-Sheen IoT.
- Xhoma kwisikhuseli esinemivalo: Shicilela okanye thenga isikhuseli semitha yelanga esineenxalenye ezininzi ezinamajelo omoya avulekileyo. Sixhome kumgama ongekho ngaphantsi kwe-1.5 yeemitha ngaphezulu komhlaba wendalo, kude kweetela eshushu okanye iitoti zophahla ezikhanyisa ilanga.
- Khusela i-PCB: Gcoba i-silicone conformal coating okanye i-acrylic lacquer kuwo onke amalungu e-solder abekwe elubala, ii-pull-up resistor, kunye nee-microcontroller, ushiye kuphela indawo evulekileyo yokulinganisa yetshiphu yokufuma ingagqunywanga.
- Faka ukufudumeza ngaphambi kokufunda kwikhowudi: Ukuba usebenzisa inzwa enesifudumezi esikwitshiphu, yongeza inkqubo emfutshane yokufudumeza kwi-measurement loop ye-microcontroller yakho ngamaxesha okurekhoda asekseni kakhulu.
Ukubeka iliso kwimozulu kwezemfundo akufuni mivuzo emikhulu yezezulu yezinga lophando, kodwa kufuna iinzwa ezakhelwe ukumelana nemichiza yokwenyani yasemoyeni. Ukusuka kwiimodyuli zangaphakathi zabathengi ukuya kwiinzwa ze-capacitive ezinomoya nezikhuselwe nge-membrane kuguqula iprojekthi yomboniso wenzululwazi ecekethekileyo yekota enye ibe sisiseko sesikolo esisisigxina, esisebenza unyaka wonke.
