Txuas Arduino Uno Nrog ESP8266: 9 Cov Kauj Ruam

2024 Tus sau: John Day | [email protected]. Kawg hloov kho: 2024-01-30 09:24

Txais tos! Koj tab tom yuav nyeem phau ntawv qhia ib qib zuj zus yuav ua li cas thiaj ua tiav txuas koj Arduino Uno rau hauv internet nrog ESP8266 (ESP-01). Nws tseem yog kuv thawj Kev Qhia Ntawv ib txwm muaj, yog li liab qab nrog kuv thov!

Cia kuv pib tawm los ntawm kev hais tias ESP8266 yog ib qho me me, tus nqi qis ntawm cov cuab yeej khoos phis tawj uas raug yog tuaj yeem qhib lub ntiaj teb loj heev, tshwj xeeb yog IOT ib qho. Mam li nco dheev tag nrho koj cov haujlwm tuaj yeem qhib tau los ntawm lub vev xaib, ua nws los ntawm koj lub xov tooj lossis pc, ntawm qhov nyem ntawm lub pob. Qhov muaj peev xwm tsis muaj qhov kawg, thiab xyov nws ua rau kuv zoo siab heev. Hmoov tsis nws tsis yog txheej txheem yooj yim thiab feem ntau koj yuav ntsib teeb meem uas kuv tsis tau ua. Txawm li cas los xij, Kuv yuav sim kuv qhov zoo tshaj los teb cov lus nug thiab hais txog txhua qhov teeb meem kuv tau ntsib!

Hloov Kho Xyoo 2020: Tsis ntev los no kuv tau hloov kho tshiab ESP8266 thiab siv kab ntawv no ua kuv tus kheej phau ntawv qhia yuav ua li cas. Kuv paub sai sai qee qhov txuas uas kuv tau muab dhau los/tsis ua haujlwm, yog li kuv tau sim hloov lawv dua. Hauv kev ua li ntawd, Kuv tau pom tias muaj cov software tshiab ntsais muag rau ESP8266, nrog rau qee cov ntaub ntawv zoo thiab hloov kho tshiab. Kuv sim kuv qhov zoo tshaj plaws los hloov kho ESP mus rau qhov ua tau zoo tshaj plaws firmware, tab sis tsis muaj kev vam meej. Lub flasher tshiab yog qhov ntse dua, tab sis tib lub sijhawm nyuaj dua. Muaj ntau txoj hauv kev rub tawm cov firmware ntau dua (uas yog qhov zoo kawg nkaus), tab sis tib lub sijhawm cov neeg siv tsis muaj lub tswv yim twg los rub tawm. Kev siv tshuab, txhua yam suab zoo tiag tiag thiab ESP thaum kawg muaj qee qhov "kev ua haujlwm" txhawb nqa thiab ntaub ntawv, tab sis tib lub sijhawm nws tau nyuaj dua. Tom qab kwv yees li 4 teev ntawm kev tshawb fawb thiab qee qhov kev sim thiab yuam kev, Kuv tau txiav txim siab tso tseg thiab tsuas yog siv tib lub flasher thiab cov ntaub ntawv kuv siv thoob plaws hauv kab lus no. Kuv tau hloov kho qhov txuas thiab tam sim no tuav lawv kuv tus kheej, yog li tsuav kuv tsis ntsia ntsia, lawv yuav nyob online tas mus li. Yog tias koj xav nyeem me ntsis ntxiv ntawm cov kev ntxiv tshiab no los ntawm zej zog, dhia mus rau theem kawg ntawm Cov Lus Qhia no qhov twg kuv tau tshaj tawm qee qhov txuas ntxiv.

Kauj ruam 1: Kho vajtse

Hloov Kho Xyoo 2020: Kuv tau pom cov vis dis aus YouTube uas txuas rau ESP yam tsis muaj kev cuam tshuam dab tsi thiab tsis muaj tus hloov pauv!

Yog lawm, yog li qhov no yog qhov nyuaj me ntsis vim tias muaj ntau txoj hauv kev los sib tham nrog ESP6288. Kuv tau sim nrhiav txoj hauv kev yooj yim tshaj plaws uas tuaj yeem ua tau thiab kuv thov txim uas qhia koj, tab sis kuv tsis xav tias koj yuav tuaj yeem ua tiav xa cov lej rau ESP yam tsis siv lub tshuab hloov me me lossis qee lub khawm … Thaum kawg kuv siv cov cuab yeej hauv qab no:

1. Arduino Ib
2. ESP8266 (ESP-01)
3. ESP8266 USB adapter
4. ESP-01 adapter
5. Hloov mus rau USB adapter
6. 4 poj niam-txiv neej jumper xov hlau
7. USB cable txuas Arduino thiab PC

Raws li koj pom, lawv tsis kim npaum li ntawd ntxiv thiab tsis tas yuav siv lub khob cij lossis tsis yog txhua tus neeg txawv txav thiab cov khoom zoo li ntawd. Nws yog txhua yam yooj yim adapters thiab thaiv.

Pom tseeb, koj yuav xav tau Arduino ntxiv rau ESP8266. Tab sis tom qab ntawd koj kuj xav tau ob lub adapters rau ESP:

• Ib tus tuaj yeem ua haujlwm rau nws (tus lej 3 ntawm daim ntawv teev npe). Qhov no kuj yog tus hloov pauv uas yuav muaj peb tus kheej hloov pauv rau nws nrog hloov pauv.
• Ib lub adapter thib ob kom koj tsis txhob tua ESP los ntawm kev txuas nws mus rau Arduino (tus lej 4 ntawm cov npe). Txij li ESP khiav 3.3V, 5V los ntawm Arduino yuav tua nws. Thiab 3.3V los ntawm Arduino tsis muaj zog txaus.

Thaum kawg, qee lub xov hlau jumper thiab USB cable txuas Arduino mus rau PC kuj tseem tsim nyog.

Kauj ruam 2: Soldering Hloov mus rau USB Adapter

Hmoov tsis zoo, txhawm rau teeb tsa ESP, koj yuav xav tau txoj hauv kev txuas nws GND Pin thiab GPIO0 Pin. Kuv tau tswj hwm kom hloov pauv me me uas cia koj xaiv yog tias koj xav nyob hauv "Hom program" lossis tsis yog. Cov vis dis aus Youtube hauv qab no yuav pab koj nrog txoj haujlwm no, Kuv pom zoo kom koj saib nws, txij li nws tseem qhia koj me ntsis txog software thiab vim li cas koj yuav tsum txuas hauv av thiab GPIO 0.

Hauv ntej, qhov no yog qhov kuv tau ua:

• Txiav ib qho ntawm cov ceg sab nraud ntawm qhov hloov, nws tuaj yeem yog sab xis lossis sab laug
• Tig lub USB adapter rov qab, thiab txuas ob txhais ceg ntawm qhov hloov mus rau GND Pin thiab GPIO0 Pin. Ceev faj kom tsis txuas lwm tus pin vim nws yuav tsis ua haujlwm tom qab.
• Ntsuas koj qhov kev hloov nrog Multimeter

Ib zaug ntxiv, yog tias tsis ntseeg, tshawb xyuas qhov Youtube txuas saum toj no.

Tsis tas li, daim duab saum toj no muaj qhov hloov pauv ntawm "Hom program". Nyob rau hauv rooj plaub koj tau siv qhov hloov pauv tib yam nkaus li kuv muaj, tam sim no koj paub tias sab twg yog "Hom program".

Thiab yog tias koj tsis nyiam qhov hloov pauv, ntawm no yog kev qhia nrog cov nyees khawm.

Kauj ruam 3: Software

Rau cov uas tab tom tshawb nrhiav txuas, ntawm no lawv yog.

ESP8266:

• Flasher
• Firmware (Kuv paub tseeb tias qhov no yuav yog qhov hloov tshiab tshaj plaws, txij li nws tsis tau hloov kho txij li Kaum Ob Hlis 2016)

Arduino Ua Haujlwm:

• Arduino IDE Cov
• Board Manager URL (Qhov no yuav tsis hloov ib yam nkaus, nws ib txwm txuas tib yam)

Thiab rau cov, uas tsis muaj lub tswv yim dab tsi cov ntawv txuas txhais tau tias, cia kuv coj koj!

1. Thawj kauj ruam yog teeb tsa Arduino IDE. Yuav tsum yooj yim zoo nkauj … Ntaus tom ntej no ntxiv thiab koj ua tiav.
2. Tom ntej no yog teeb tsa IDE kom koj tuaj yeem tsim kho koj li ESP. Txhawm rau ua qhov no, koj yuav tsum mus rau Cov Ntaub Ntawv -> Nyiam thiab hauv qab hauv qab Tus Thawj Saib Xyuas Lub Rooj Sib Tham Ntxiv: muab tshuaj txhuam URL hauv qab no.
3. Tom qab ntawv mus rau cov cuab yeej -> Pawg Thawj Coj -> Tus Thawj Saib Xyuas Haujlwm thiab nqes mus txhua qhov kom txog thaum koj pom ib qho hu ua esp8266 thiab ntaus nruab. Tseeb Version thov. Thaum nws ua tiav kev teeb tsa rov pib dua IDE.
4. Tam sim no mus rub ob lub flasher thiab firmware rau ESP. Tsim daim nplaub tshev ntawm koj lub desktop hu ua "Flasher" thiab unzip ob daim ntawv rub tawm hauv nws. Peb yuav xav tau lawv tom qab.

Zoo, tam sim no koj yuav tsum muaj txhua lub software xav tau los ua haujlwm ESP!

Kauj Ruam 4: Xeem ESP

Tom ntej no yog koj thawj qhov kev sib txuas nrog ESP. Ib feem no yog qhov nyuaj me ntsis thiab qhov ua haujlwm rau kuv yuav tsis ua haujlwm rau koj… Cia peb cia siab rau qhov zoo tshaj plaws.

Cia peb pib los ntawm kev rub tawm daim duab ua ntej uas ntsais muag xiav LED ntawm ESP. Txhawm rau ua qhov no, koj yuav xav tau cov hauv qab no:

• Ib qho hloov pauv USB adapter rau ESP, yog li koj tuaj yeem teeb nws rau "Program hom". Kauj Ruam 2 ntawm Cov Lus Qhia no.
• Paub dab tsi USB chaw nres nkoj (COM chaw nres nkoj) koj ESP yuav txuas nrog.

Yog tias koj tsis paub qhov chaw nres nkoj COM, tsis txhob txhawj xeeb. Nws yog ib qho yooj yim mus nrhiav tau. Qhib koj tus IDE thiab nyem rau ntawm cov cuab yeej -> Chaw Nres Nkoj thiab sau tseg ntawm Cov Chaw Nkoj uas tau teev tseg. Tom qab ntawd, ntxig koj lub USB adapter thiab mus xyuas cov npe teev tseg dua. Qhov tshiab yog COM chaw nres nkoj koj tab tom nrhiav!

PS: Kuv yog tus siv windows. Yog tias kuv rov hais dua kom raug, Macs tsis hu lawv cov chaw nres nkoj COM. Txawm li cas los xij, nws tseem yuav tsum ua haujlwm!

Yog li tam sim no koj paub koj Chaw Nkag, xav tias dawb los ntsaws koj lub USB adapter rau! Nws yuav tsum yog "Hom phiaj", ua lwm yam lus, GND thiab GPIO0 yuav tsum txuas nrog. Qhib IDE thiab mus rau Cov Cuab Yeej -> Pawg Thawj Coj thiab xaiv Cov Qauv Tseem Ceeb ESP8266. Tom qab ntawd, hauv Cov Cuab Yeej kom ntseeg tau tias koj muaj cov teeb tsa hauv qab no:

• Pawg thawj coj: "Generic ESP8266 Module"
• Chaw nres nkoj: Koj qhov chaw nres nkoj COM

Thaum kawg, mus rau Cov Ntaub Ntawv -> Piv txwv -> ESP8266 -> Blink thiab nyem rau ntawm lub cim me me nyob rau sab saud sab laug ntawm IDE. Qhov no yuav txheeb xyuas koj cov cai thiab qhia koj yog tias muaj qee yam tsis raug nrog nws. Kuv pom zoo koj ua qhov no txhua lub sijhawm ua ntej rub cov duab kos rau ESP lossis Arduino! Yog tias ua tiav, koj yuav pom "Ua tiav ua ke." ntawv. Qhov tsuas yog tshuav tam sim no yog nyem lub cim "sab xis" nyob rau sab laug sab saum toj ntawm IDE txhawm rau txhawm rau rub cov cai. Yog tias txhua yam raug teeb tsa kom raug, koj yuav tsum pom nws tau rub tawm thiab thaum kawg ua tiav. Ua tibzoo saib koj li ESP, nws yuav tsum muaj lub ntsais ntsais LED! Nrog koj zoo siab, koj nyuam qhuav tso koj thawj qhov haujlwm rau koj li ESP!

Yog tias koj tau txais qhov yuam kev tab sis, tsis txhob txhawj xeeb. Tej zaum qhov hloov pauv tsis nyob ntawm sab xis. Tshem koj lub USB adapter thiab "hloov qhov hloov", ntsaws nws rov qab thiab rov ua cov txheej txheem. Yog tias nws ua haujlwm koj paub tias qhov ntawd yog "Hom program" sab! Yog tias tseem tsis ua haujlwm, ces hmoov zoo. Qhov ntawd yog qhov kuv xav nrog "dab tsi ua haujlwm rau kuv yuav tsis ua haujlwm rau koj" … Tshaj tawm cov lus nug/teeb meem hauv cov lus thiab kuv yuav sim kuv qhov zoo tshaj plaws los pab!

PS: Ua siab zoo sim lwm qhov piv txwv! Tej zaum Cov Ntaub Ntawv -> Piv txwv -> ESP8266Wifi -> WifiScan. Tom qab rub tawm, qhib cov Cuab Yeej -> Saib Xyuas Serial thiab tos ob peb feeb. Yog tias tsis muaj dab tsi tshwm sim, ib qho teeb tsa Baud rau 9600 lossis 115200. Thiab siv "Ob NL & CR". Ntau ntxiv txog qhov no tom qab hauv kab lus no, yog li tsis txhob txhawj xeeb yog tias koj tsis tau txais lus teb!

Kauj Ruam 5: Xeem AT Cov Lus txib

Kuv hu cov kauj ruam no xaiv vim tias tsis muaj tag nrho AT cov lus txib ua haujlwm rau kuv thaum xub thawj. Txawm hais tias kuv paub tseeb tias ESP tau ua haujlwm zoo vim tias nws tau ntsais nrog cov duab kos yav dhau los thiab kuv kuj tau tswj xyuas kom pom Wifi. Tab sis txhua lub sijhawm kuv sim tham nrog nws dhau AT cov lus txib Kuv yuav tsis tau txais lus teb. Txawm li cas los xij, Kuv yuav qhia koj cov kauj ruam uas kuv tau ua los tham nrog nws. Yog tias nws tsis ua haujlwm, dhia mus rau kauj ruam tom ntej.

Txuas koj ESP rau hauv USB adapter thiab ntsaws rau hauv koj lub PC. Nco ntsoov tias nws tsis nyob hauv "Hom program"! Mus rau Cov Cuab Yeej thiab hloov Pawg Thawj Coj mus rau Generic ESP8266 Module. Xyuas kom tseeb tias qhov chaw nres nkoj raug xaiv raug xaiv thiab tom qab ntawd qhib Serial Monitor (Ctrl + Shift + M) thiab teeb tsa cov hauv qab no:

• Ob leeg NL & CR
• 115200 Nws

Yog tias txhua yam raug, sim ntaus "AT" rau ntawm kab sab saum toj thiab ntaus nkag. Koj yuav tsum tau txais "OK" rov qab. Yog tias koj tau txais "OK", tom qab ntawd haus luam yeeb dawb huv koj tsuas yog tswj tau txuas nrog koj li ESP thiab koj tuaj yeem txaus siab thiab zoo siab! Hom tom ntej "AT+GMR" kom tau txais xov xwm ntau ntxiv txog koj li ESP. Nyob rau hauv rooj plaub SDK version yog 1.54 ces koj kuj tseem tuaj yeem dhia "Flashing qhov tseeb Firmware" kauj ruam vim koj twb muaj nws lawm.

Yog tias koj tsis tau txais cov lus teb, xav rov sim dua thiab/lossis hloov tus nqi Baud. Kuv pom zoo tsis "nkim sijhawm" ntau dhau nrog qhov no, txij li koj paub tias koj li ESP ua haujlwm vim yog Kauj Ruam 4.

PS: Yog tias IDE xav kom koj khaws daim duab ua ntej txheeb xyuas/tso nws, tsis txhob khaws nws. Kuv tau muaj qee qhov teeb meem nrog kev khaws cov ntaub ntawv thiab cov ntawv saib tom qab ntawd tsis ua haujlwm. Kuv tsis paub tseeb tias vim li cas tseem, tau ua qee qhov kev sim ntau dua, tab sis kuv qhia koj kom tsis txhob txuag koj cov duab.

Kauj Ruam 6: Ua kom pom qhov tseeb Firmware

Txawm hais tias cov kauj ruam dhau los tsis ua haujlwm rau koj, sim hloov kho nws cov firmware nrog cov kauj ruam no, tej zaum nws yuav kho nws!

Tam sim no koj paub yuav ua haujlwm li cas rau koj li ESP, nws yog lub sijhawm hloov kho nws cov firmware! Pib los ntawm ntsaws koj ESP rau hauv USB adapter thiab tom qab ntawd xaiv lub Rooj Tswjhwm Saib txoj cai thiab Chaw nres nkoj rau nws. Tsis txhob hnov qab muab nws tso rau hauv "Hom program", lwm qhov flashing yuav tsis ua haujlwm!

Tom ntej no, koj yuav tsum qhib daim nplaub tshev uas koj tau tsim ntawm "Kauj Ruam 2: Software" nco qab? Nrog lub flasher thiab cov ntaub ntawv.bin. Qhib nws, thiab khiav esp8266_flasher.exe. Yog nug txog txoj cai tswjfwm, hais tias yog. Tam sim no tseem yog lub sijhawm zoo los kaw IDE, tsuas yog kom ntseeg tau tias tsis muaj dab tsi cuam tshuam. Nyem rau ntawm Bin khawm thiab xaiv cov ntaub ntawv npe "AiThinker_ESP8266_DIO_8M_8M_20160615_V1.5.4.bin". Xyuas kom tseeb tias koj Port yog qhov raug, tias lub qhov rai tom ntej tau teeb tsa rau 0x00000 thiab koj li ESP nyob hauv "Hom program" thiab nyem rau Download. Nws yuav tsum pib rub tawm lub khoos phis tawj mus rau koj li ESP thiab lub xiav LED yuav tsum ci. Tos me ntsis kom txog thaum nws ua tiav.

Thaum nws ua tiav, koj yuav tau txais txiaj ntsig nrog "Ua tsis tau tawm ntawm Flash hom" yuam kev, uas yog qhov zoo. Tsis quav ntsej nws thiab kaw lub flasher. Koj nyuam qhuav hloov kho koj li ESP's firmware! Zoo.

Yog tias koj muaj qhov tsis raug, rov ua dua: Nco ntsoov tias koj Chaw nres nkoj yog qhov raug, tias lub qhov rai tom ntej tau teeb tsa 0x00000 thiab koj li ESP nyob hauv "Hom program"! Yog tias nws tseem tsis ua haujlwm, ces kuv xav hais tias koj qhov kev hloov pauv tsis ua haujlwm raug.

Thaum kawg, koj yuav xav sim tham nrog koj li ESP los ntawm AT tam sim no, ua tibzoo saib ntawm "Test AT Commands" kauj ruam. Yog tias nws tseem tsis ua haujlwm, tsis txhob txhawj xeeb. Mus tom ntej thiab tso Blink piv txwv ntxiv kom paub tseeb tias koj tsis ua txhaum koj li ESP. Yog tias nws ua haujlwm, koj tseem zoo mus!

Kauj Ruam 7: Txuas Arduino thiab ESP

Nov yog cov theem yooj yim uas qhia koj yuav ua li cas txuas ESP rau Arduino Uno! Raws li tau hais hauv kauj ruam "Kho vajtse", Kuv tau siv ESP-01 Adapater.

Ua ntej tshaj, ntsaws koj ESP mus rau ESP-01 Adpater thiab xyuas kom nws tau ntsib txoj hauv kev! Tom ntej no, lob koj 4 jumper xov hlau thiab txuas lawv zoo li no:

• Pin 3 ntawm Arduino rau Pin RX ntawm Adapter
• Pin 2 ntawm Arduino rau Pin TX ntawm Adapter
• Pin 5.5V ntawm Arduino rau Pin VCC ntawm Adapter
• Pin GND ntawm Arduino rau Pin GND ntawm Adapter

Tooj tiav lawm. Yooj yim pzy txoj cai?

PS: Kuv pom zoo siv xaim liab rau txuas 5V thiab xaim dub rau GND txuas. Nws tsuas yog tus qauv hauv cov khoom siv hluav taws xob.

Kauj Ruam 8: Xaus + Yam Yuav Tsum Nco

Yog lawm, yog tias koj tau ua raws kuv phau ntawv qhia thiab kuv tsis tau ua dab tsi li, koj yuav tsum tam sim no yam tsawg kawg tuaj yeem muaj ESP ua haujlwm nrog kho tshiab Firmware. Tej zaum nws txawm tham nrog koj thiab koj rau nws, qhov ntawd yuav zoo tag nrho! Mus tom ntej thiab tshawb nrhiav lub ntiaj teb zoo ntawm IOT thiab zoo li no. Tej zaum koj yuav xav qhib lub teeb ntawm qhov nyem ntawm lub pob ntawm koj lub xov tooj, lossis tej zaum tig rau qhov dej hauv koj lub vaj (zoo li kuv tab tom sim ua). Kuv tsis paub, kuv yuav cia koj xaiv. Xav tias dawb sau qee cov lus tawm tswv yim/lus nug txog cov lus qhia hauv qab no!

Tsuas yog qee yam ntxiv kom nco ntsoov:

• Thaum xa cov cai rau koj Arduino, Pin 0 (RX) yuav tsum tau dawb!
• Yog tias koj tab tom khiav koj li ESP los ntawm 3.3V tawm ntawm Arduino, ceev faj nws yuav tsis muaj zog txaus thiab koj yuav tau txais yuam kev vim nws! Kuv pom zoo ESP-01 Adapater.

• Yog tias koj xav tham nrog koj ESP hla Arduino thiab tsis yog USB Adapter, koj yuav tsum ua cov hauv qab no:

  1. Qhov Tsim Nyog: Koj yuav tsum muaj peev xwm tham nrog AT cov lus txib nrog koj li ESP hla lub USB adapter kom hloov tau!
  2. Mus tom ntej thiab ntsaws koj lub USB adapter nrog ESP. Nco ntsoov tias nws tsis nyob ntawm "Hom program"!
  3. Xaiv ESP8266 Pawg Thawj Coj thiab kho qhov chaw nres nkoj thiab qhib Serial Monitor (115200 Baud).
  4. Ntaus "AT" thiab tau txais "OK" rov qab.
  5. Peb yuav tau hloov pauv Baud tus nqi ntawm ESP nrog cov lus txib hauv qab no: "AT+UART_DEF = 9600, 8, 1, 0, 0" (lossis rau qee qhov qauv "AT+CIOBAUD = 9600").
  6. Koj yuav tsum tau txais "OK" rov qab lossis qee yam kev lees paub.
  7. Kaw Serial Monitor.
  8. Tshem lub USB adapter thiab ntsaws koj ESP rau hauv Arduino adapter. Txuas tus adapter rau Arduino zoo li qhia hauv kauj ruam "Txuas Arduino thiab ESP".
  9. Txuas Arduino nrog koj lub PC.
  10. Hloov Pawg Thawj Coj rau Arduino thiab xaiv qhov chaw nres nkoj raug.
  11. Upload cov cai no rau Arduino.
  12. Qhib Serial Monitor ib zaug ntxiv, tab sis lub sijhawm no ntawm 9600 Baud.
  13. Tam sim no koj yuav tsum tuaj yeem ntaus "AT" thiab tau txais "OK" rov qab.

Kauj ruam 9: Txuas

Nov yog cov npe ntawm qee qhov txuas uas kuv pom hauv lub vev xaib uas tau pab kuv, thiab lawv kuj tseem yuav pab tau koj!

• Sketch rau Arduino Uno txhawm rau tham nrog ESP
• Teem koj ESP rau hauv "hom phiaj" nrog hloov lossis khawm

Hloov tshiab 2020:

• Phau ntawv qhia yuav ua li cas nyem nrog lub software flasher tshiab
• Pib los ntawm Espressif
• Flasher thiab SDK/AT rub los ntawm Espressif
• Cov ntaub ntawv dav dav txog feem ntau ntawm txhua yam uas tau hais hauv kab lus no (suav nrog cov ntaub ntawv yuav ua li cas nyem ESP yam tsis muaj cov hloov pauv)