Izinzwa zomswakama womhlabathi ezishibhile ezinamaphondo amabili ziyahluleka ezinsukwini ezimbalwa engadini yesikole ngoba empeleni ziyizifunda zikagesi ze-electroplating ezisebenza ngokuhlehla. Uma ushiya inzwa ye-resistive enemizila evuleliwe ixhunywe kwirheyili ye-3.3V noma ye-5V emhlabathini omanzi ocebile ngamaminerali, ugesi oqondile (DC) ongaphezi uqhuba i-electrolysis esheshayo. Iprobhu ephozithivu isebenza njenge-anode: iyagqwala nge-oxidation, ikhiphele ungqimba lwayo lwethusi emhlabathini kuze kuphuke ngokuphelele umzila.

Ezikoleni zaseNingizimu Afrika ezakha amaphrojekthi okunisela okuzenzakalelayo noma ezolimo ezihlakaniphile ngaphansi kwekharikhulamu ye-CAPS ye-Coding and Robotics, le ndlela yokwehluleka iguqula iphrojekthi yethemu lonke ibe yisivivinyo esifile ngaphambi kokuhluma kwesithombo sokuqala. Ngenhlanhla, isixazululo asidingi amaprobhu ezimboni abizayo noma ukuklama kabusha okuyinkimbinkimbi.

Ikhemistri: Kungani Amaprobhu e-Resistive Ezibhubhisa

Izinzwa ezijwayelekile ze-resistive zomswakama womhlabathi zisebenza ngokudlulisa ugesi phakathi kwemizila emibili evuleliwe edlulisa ugesi. Ukumelana kukagesi phakathi kwamaphondo kuguquka ngokuphambene nobuningi bamanzi: umhlabathi owomile unokumelana kukagesi okuphezulu, kanti umhlabathi omanzi udlulisa ugesi kalula.

Nokho, amanzi asemhlabathini akuwona i-H₂O emsulwa. Ayisisombululo se-electrolyte esinosawoti bamaminerali ancibilikile, ama-nitrate omanyolo, kanye nama-ion aphilayo. Uma kufakwa i-voltage ye-DC engaphezi:

• I-oxidation ye-anode yenzeka kuprobhu ephozithivu: Ama-athomu ethusi alahlekelwa ama-electron bese encibilika angene emhlabathini njengama-ion ethusi (Cu → Cu²⁺ + 2e^-).
• Ukwehliswa kwe-cathode kwenzeka kuprobhu enegethivu: Amanzi noma ama-ion e-hydrogen athola ama-electron, ngokuvamile akhe amabhamuza egesi ye-hydrogen amancane kakhulu noma adonse ukwakheka kwamaminerali.
• Imizila yethusi iyabhidlika: Phakathi kwesonto noma amabili, ungqimba oluncane lwegolide noma lwethini luyahluthuka, ithusi elingaphansi liphenduka libe mnyama-luhlaza, bese isifunda sikagesi sivuleka unomphela.

Izibalo zenzwa ziyaphambuka kakhulu njengoba insimbi idleka, okwenza noma yiliphi izinga eliqondiswe kuphampu ezenzakalelayo lingasebenzi ngaphambi kokuthi iprobhu ihluleke ngokuphelele.

Enye Indlela 1: Izinzwa Ze-Capacitive Zomswakama Womhlabathi (Ezinconywayo)

Isixazululo esijwayelekile embonini yama-microcontroller emfundo (i-ESP32, i-micro:bit, noma i-Arduino) yinzwa ye-analog ye-capacitive yomswakama womhlabathi (evamise ukuthengiswa njengeprobhu ye-capacitive ye-v1.2 noma ye-v2.0).

Esikhundleni sokudlulisa ugesi oqondile emhlabathini, iprobhu ye-capacitive ikala ushintsho ku-capacitance kagesi olubangelwa yi-dielectric permittivity yomhlabathi. Amanzi ane-permittivity ephakeme kakhulu (≈ 80) uma kuqhathaniswa nezinto eziqinile zomhlabathi owomile (≈ 3 kuya ku-5) nomoya (≈ 1). Njengoba umswakama womhlabathi wanda, i-capacitance ezungeze iprobhu iyakhuphuka, ishintshe i-frequency yesifunda se-555-timer esikubhodi noma ye-oscillator ye-frequency ephezulu, ibhodi elikuguqula kube yi-analog voltage ephumayo.

Kungani Amaprobhu e-Capacitive Engagqwali

• Alikho ithusi elivuleliwe emhlabathini: Imizila edlulisa ugesi ivalwe ngokuphelele ngaphansi kongqimba lwe-solder mask lwe-PCB. Ayikho insimbi ethinta umhlabathi omanzi ngqo.
• Awukho umzila kagesi oqondile: Ngoba asikho isifunda se-galvanic esivaliwe esidlula emanzini omhlabathi, i-electrolysis ayinakwenzeka.
• Ukungathinteki ngobusawoti bomhlabathi: Izinzwa ze-resistive zinikeza izibalo ezingamanga zomswakama ophezulu uma ufaka umanyolo, ngoba ama-ion engeziwe ehlisa ukumelana kukagesi. Izinzwa ze-capacitive azithinteki kangako ekudluliseni ugesi kwamaminerali.

Ezinhlelweni zemfundo, ukuhlola amakhithi asekulungele ukusetshenziswa njengalawo akwikharikhulamu ye-Sheen Robotics Smart Agriculture kunikeza izinzwa ze-capacitive esezilinganisiwe ezenzelwe ngqo ama-microcontroller asekilasini.

Enye Indlela 2: Ugesi Olawulwa Yisofthiwe (Ukusebenzisa I-Duty Cycle Kumaprobhu e-Resistive)

Uma isikole sakho sesivele sathenga isethi yekilasi yezinzwa ze-resistive ezishibhile futhi singakwazi ukuzishintsha ngokushesha, ungakwazi ukwelula impilo yazo kusuka emasontweni amabili kuye ezinyangeni eziningana ngokusebenzisa ugesi olawulwa yisofthiwe.

Esikhundleni sokuxhuma i-pin ye-VCC yenzwa ngqo ku-pin ehlala njalo ye-3.3V noma ye-5V ye-microcontroller, xhuma i-VCC ku-pin yedijithali ephumayo (noma ku-transistor yokushintsha uma inzwa idonsa ugesi ongaphezu kwalowo i-pin ye-GPIO engawunikeza ngokuphepha):

1. Gcina i-pin yedijithali ye-GPIO isethelwe ku-LOW (0V) ngesikhathi esejwayelekile sokulinda.
2. Uma uthatha isibalo (isb., kanye njalo emizuzwini engu-30), setha i-pin ye-GPIO ibe ku-HIGH.
3. Linda ama-millisecond angu-20 kuya kwangu-50 ukuze isibalo se-analog sizinze.
4. Funda inani le-ADC nge-pin ye-analog.
5. Buyisela i-pin ye-GPIO ku-LOW ngokushesha.

Ukwehlisa i-duty cycle kusuka kugesi ongaphezi ongu-100% kuye kuma-millisecond angu-50 ngesigamu sehora kunciphisa ukuchayeka konke kwe-electrochemical ngamaphesenti acishe abe ngu-99.97%, kwehlise ukugqwala kuye kwesivinini esingabalulekile.

Ukuqhathaniswa Okusebenzayo Kwamaphrojekthi e-IoT Asekilasini

Ukuxhuma Nokuvikela Izinzwa Zengadi Ngokoqobo

Uma ufaka amaprobhu e-capacitive kuthaneli yesikole, embhedeni wengadi ophakanyisiwe, noma esitshalweni esisembizeni sangaphakathi, khumbula imininingwane emithathu yokufaka:

• Vikela emanzini ama-electronics asebhodini: Amaprobhu e-capacitive aphephile emhlabathini kuze kufike kumugqa omhlophe oboniswe ku-PCB. Ingxenye engenhla yebhodi—equkethe i-IC efakwe ngaphezulu, ama-resistor, kanye nesihloko sezintambo—ayivikelekile emanzini. Ukujiya kwamanzi noma ukunisela kusukela phezulu kuzoshisa lezi zingxenye. Vala ama-cm angu-2 aphezulu ngethumbu le-heat-shrink elicacile eligcwaliswe ngoglue oshisayo noma ngongqimba lwe-conformal silicone.
• Qaphela i-voltage esebenzayo: Izinzwa eziningi ze-capacitive ezishibhile zisebenzisa i-IC yesikhathi edinga okungenani i-3.3V kuya ku-5V. Uma uxhuma kumabhodi e-3.3V afana ne-ESP32 noma i-BBC micro:bit, qinisekisa ukuthi lolo hlobo lwenzwa lungasebenza luzinzile ku-3.3V; uma kungenjalo, isignali ephumayo izogcwala ku-voltage yerheyili kungakhathaliseki ukuthi umhlabathi umanzi kangakanani.
• Kalibhreyitha emoyeni nasemanzini: Izinombolo ze-ADC eziluhlaza (ezifana no-0–4095 ku-ESP32) azisho lutho kubafundi. Yenza abafundi barekhode inani eliluhlaza emoyeni owomile (izinga eliyisisekelo lomswakama elingu-0%) nalapho icwiliswe kuze kufike kumugqa enkomishini yamanzi (izinga eliyisisekelo elingu-100%), bese bebhala imephu elula noma umsebenzi we-interpolation nge-MicroPython noma nge-MakeCode ukuze baguqule isibalo sibe yiphesenti.

Uma uklama izinhlelo zokuqapha imvelo ezixhunyiwe okudingeka zimelane nesimo sezulu saseNingizimu Afrika, ukucishwa kukagesi, namakhefu amade amaholide, bheka amapulani asehlolwe ekilasini ku-Sheen IoT ukuze uthole izinhlelo zensimbi ezifakazelwe.