Tswj Teeb Nrog Koj Lub Qhov Muag: 9 Kauj Ruam (nrog Duab)

2024 Tus sau: John Day | [email protected]. Kawg hloov kho: 2024-01-30 09:25

Lub semester no hauv tsev kawm qib siab, Kuv tau kawm ib chav hu ua Instrumentation in Biomedicine uas kuv tau kawm cov hauv paus ntawm kev teeb liab rau kev thov kho mob. Rau chav kawm qhov kawg, kuv pab neeg ua haujlwm ntawm EOG (electrooculography) thev naus laus zis. Qhov tseem ceeb, cov hluav taws xob txuas rau ib tus neeg lub tuam tsev xa qhov sib txawv ntawm qhov sib txawv (raws li lub qhov muag-retinal dipole) mus rau qhov Circuit Court tsim los lim thiab ua kom nrov nrov. Lub teeb liab tau pub rau ADC (analog-rau-digital hloov pauv-hauv kuv qhov xwm txheej, ADC ntawm Arduino Uno) thiab siv los hloov cov xim ntawm cov pob zeb neopixel.

Phau ntawv qhia no yog ib txoj hauv kev rau kuv sau qhov kuv tau kawm, thiab tseem qhia nrog cov nyeem ib txwm ua li cas cov cim tau raug cais tawm ntawm tib neeg lub cev (yog li ceeb toom: nws muaj ntau yam ntxiv!). Qhov kev siv hluav taws xob no tuaj yeem siv tau, nrog rau qee qhov kev hloov pauv me me, kom lub siab lub cev muaj zog 'hluav taws xob ua hluav taws xob raws li EKG kev hloov pauv, thiab ntau ntxiv! Thaum nws yeej tsis pom qhov twg ze tshaj thiab ua tiav zoo li cov tshuab uas koj yuav pom hauv tsev kho mob, lub teeb-qhov muag-tswj lub teeb yog qhov zoo rau kev nkag siab thawj zaug thiab kev pom.

Nco tseg: Kuv tsis yog tus kws tshaj lij hauv kev teeb liab yog li yog muaj qhov ua yuam kev lossis yog tias koj muaj lus qhia rau kev txhim kho, thov qhia rau kuv paub! Kuv tseem muaj ntau yam los kawm yog li kev tawm tswv yim zoo siab. Tsis tas li, ntau daim ntawv uas kuv siv hauv kev sib txuas hauv txhua qhov kev qhia no xav tau kev kawm nkag mus uas kuv tau txais txiaj ntsig los ntawm kuv lub tsev kawm ntawv; thov txim ua ntej rau cov neeg uas yuav tsis muaj kev nkag tau.

Kauj ruam 1: Cov ntaub ntawv

• protoboard
• resistors (100, 1k, 10k, 33k, 1M + 0.5M)
• capacitor (0.1uF)
• ntsuas ntsuas amp (INA111 hauv kuv rooj plaub, tab sis muaj ob peb uas yuav tsum ua haujlwm tau zoo)
• op amp (ib qho - Kuv tau muaj LM324N)
• neopixel (ib qho haujlwm, tab sis kuv siv pob zeb diamond)
• 9v x 2 v
• 9V roj teeb lub taub hau x2
• cov khoom siv hluav taws xob gel (xaiv cov electrode tau tham hauv qib 5)
• potentiometer
• insulated hlau
• cov hlua hlau
• soldering hlau + solder
• cov yeeb yaj kiab (nrog cov xov txuas nrog - muab qee yam tso rau hauv yog tias tsim nyog)
• kua nplaum kub (kom ruaj khov cov xov hlau uas yuav khoov rov qab los)
• Arduino (zoo nkauj npaum li lub rooj tsavxwm ua haujlwm, tab sis kuv siv Arduino Uno)

RECOMMEND HIGHLY: oscilloscope, multimeter, thiab lub tshuab hluav taws xob ua haujlwm. Kuaj koj cov txiaj ntsig ntau dua li tsuas yog cia siab rau kuv qhov kev tiv thaiv tus nqi!

Kauj Ruam 2: Lub Cev Muaj Zog Tom Qab thiab Xav Tau Kev Sib Txuas

Kev lees paub sai: Kuv tsis yog tus kws tshaj lij kho mob hauv daim teb no, tab sis kuv suav sau thiab yooj yim dua qhov kuv tau kawm hauv chav kawm/los ntawm Google hauv qab no, nrog txuas rau kev nyeem ntxiv yog tias koj xav tau. Tsis tas li, qhov txuas no yog nyob deb ntawm qhov zoo tshaj plaws ntawm cov ncauj lus uas kuv pom - suav nrog lwm txoj hauv kev.

EOG (electro-oculography) ua haujlwm ntawm corneo-retinal dipole. Lub qhov muag (lub hauv ntej ntawm lub qhov muag) tau them me ntsis zoo thiab lub qhov muag (sab nraum lub qhov muag) raug them me ntsis. Thaum koj siv cov hluav taws xob tso rau ntawm cov tuam tsev thiab ua av hauv av rau koj lub hauv pliaj (pab ua kom ruaj khov rau koj nyeem thiab tshem qee qhov cuam tshuam 60Hz), koj tuaj yeem ntsuas ib puag ncig ~ 1-10mV qhov sib txawv qhov sib txawv rau kab rov tav qhov muag pom (saib daim duab saum toj no). Txog rau qhov muag txav ntawm qhov muag, tso hluav taws xob saum toj thiab hauv qab koj lub qhov muag hloov. Saib kab ntawv no kom nyeem tau zoo li cas lub cev cuam tshuam nrog hluav taws xob - cov ntaub ntawv zoo ntawm daim tawv nqaij tsis txaus, thiab lwm yam. EOGs feem ntau siv rau kev kuaj mob kab mob ophthalmological xws li cataracts, tsis pom kev tsis zoo, lossis macular degeneration. Kuj tseem muaj daim ntawv thov nyob rau hauv qhov muag tswj cov neeg hlau uas cov haujlwm yooj yim tuaj yeem ua nrog qhov muag ntawm.. qhov muag.

Txhawm rau nyeem cov cim no, piv txwv li suav qhov sib txawv ntawm qhov sib txawv ntawm cov hluav taws xob, peb suav nrog ib qho tseem ceeb nti hu ua qhov ntsuas qhov ntsuas hluav taws xob rau hauv peb lub Circuit Court. Qhov ntsuas qhov ntsuas no suav nrog cov ntsuas hluav taws xob, lub amp tsis hloov pauv, thiab qhov sib txawv amp. Yog tias koj tsis paub ntau txog op amps, thov nyeem qhov no rau chav kawm sib tsoo - qhov tseem ceeb, lawv siv qhov hluav taws xob nkag, ntsuas nws, thiab tso tawm qhov tshwm sim qhov hluav taws xob siv nws cov ntsia hlau. Kev koom ua ke ntawm txhua tus tiv thaiv hauv nruab nrab ntawm txhua theem pab nrog kev ua yuam kev: ib txwm resistors muaj 5-10% kev ua siab ntev hauv qhov muaj txiaj ntsig, thiab kev sib txuas ib txwm muaj (tsis suav nrog hauv kev ntsuas amp) yuav ua rau muaj kev ntseeg siab rau qhov zoo CMMR (saib cov kauj ruam tom ntej)). Cov ua raws qhov hluav taws xob yog rau cov lus tawm tswv yim siab (tham hauv nqe lus saum toj no - qhov tseem ceeb rau kev tiv thaiv kev puas tsuaj rau tus neeg mob), qhov tsis hloov pauv amp yog txhawm rau kom tau txais txiaj ntsig siab ntawm lub teeb liab (ntau ntxiv ntawm kev hloov pauv hauv cov kauj ruam tom ntej) thiab qhov sib txawv amp siv qhov sib txawv nruab nrab ntawm cov tswv yim (rho tawm qhov muaj txiaj ntsig los ntawm cov electrodes). Cov no yog tsim los tsoo ntau hom suab nrov/cuam tshuam ntau li ntau tau (xav paub ntau ntxiv ntawm kev teeb liab, saib cov kauj ruam tom ntej) rau cov cim qhia txog kab mob, uas muaj ntau heev nrog cov khoom cuav.

Cov hluav taws xob tau ntsib qee qhov tsis txaus ntawm daim tawv nqaij txij li koj cov tawv nqaij cov nqaij thiab rog cuam tshuam qhov ntsuas ncaj qha ntawm qhov hluav taws xob, ua rau xav tau lub teeb liab nthuav dav thiab lim. Ntawm no, ntawm no, thiab ntawm no yog qee cov ntawv uas cov kws tshawb fawb tau sim ua kom muaj nuj nqis qhov cuam tshuam no. Qhov lub cev muaj nuj nqis no feem ntau ua qauv raws li 51kOhm resistor ua ke nrog 47nF capacitor, txawm hais tias muaj ntau qhov kev hloov pauv thiab ua ke. Cov tawv nqaij nyob hauv ntau qhov chaw tuaj yeem muaj qhov cuam tshuam sib txawv, tshwj xeeb tshaj yog thaum koj txiav txim siab qhov tuab sib txawv thiab ntau npaum li cas ntawm cov leeg ib sab. Impedance kuj tseem hloov pauv zoo npaum li cas koj cov tawv nqaij tau npaj rau hluav taws xob: ntxuav kom huv nrog xab npum thiab dej feem ntau tau qhia kom ntseeg tau tias muaj cov nplaum zoo thiab sib xws, thiab tseem muaj cov xim tshwj xeeb rau cov electrodes yog tias koj xav tau kev ua tiav. Ib daim ntawv tseem ceeb yog qhov cuam tshuam hloov pauv nrog zaus (tus yam ntxwv ntawm lub capacitors) yog li koj yuav tsum paub koj li teeb liab bandwidth txhawm rau kwv yees kev cuam tshuam. Thiab yog, kwv yees kev cuam tshuam yog ib qho tseem ceeb rau kev sib txuas suab nrov - saib tom qab theem rau cov ntaub ntawv ntau ntxiv txog qhov no.

Kauj Ruam 3: Ua Teeb Meem: Vim Li Cas thiab Li Cas?

Tam sim no, vim li cas koj thiaj tsis tuaj yeem siv qhov sib txawv ntawm 1-10mV qhov hluav taws xob tam sim ntawd los tswj LEDs? Zoo, muaj ntau qhov laj thawj rau kev lim dej thiab ua kom nrov nrov:

• Ntau ADCs (analog-rau-digital hloov pauv-siv koj cov lus sib piv thiab digitize lawv rau kev nyeem thiab khaws cov ntaub ntawv hauv computer) tsuas yog tsis tuaj yeem pom qhov kev hloov pauv me me. Piv txwv li, Arduino Uno's ADC tshwj xeeb yog 10-ntsis ADC nrog 5V tso tawm, lub ntsiab lus tias nws qhia 0-5V cov khoom siv hluav taws xob (tawm ntawm ntau qhov txiaj ntsig yuav "kev tsheb nqaj hlau," lub ntsiab lus uas qis dua yuav raug nyeem raws li 0V thiab qhov siab dua nyeem raws li 5V) mus rau qhov muaj nuj nqis nruab nrab ntawm 0 thiab 1023. 10mV yog qhov me me hauv qhov 5V ntau, yog li yog koj tuaj yeem ua kom koj lub teeb liab mus rau tag nrho 5V ntau yam, kev hloov pauv me me yuav nkag tau yooj yim dua vim tias lawv yuav pom los ntawm kev hloov pauv loj dua (5mV hloov mus rau 10mV tsis zoo li 2V hloov mus rau 4V). Xav txog nws zoo li daim duab me me hauv koj lub khoos phis tawj: cov ntsiab lus tuaj yeem txhais tau zoo los ntawm koj lub pixels, tab sis koj yuav tsis tuaj yeem sib txawv cov duab tshwj tsis yog koj nthuav daim duab.

  Nco ntsoov tias muaj ntau qhov ntxiv rau koj ADC yog qhov zoo dua vim tias koj tuaj yeem txo qis suab nrov los ntawm kev xa koj lub teeb liab txuas mus rau qhov kev txiav txim siab, digitized qhov tseem ceeb. Txhawm rau suav pes tsawg cov khoom koj xav tau rau ~ 96% khaws cia ntawm cov ntaub ntawv SNR, siv N = SNR (hauv dB)/6 raws li txoj cai ntawm tus ntiv tes xoo. Koj kuj tseem xav khaws koj lub hnab nyiaj hauv siab txawm hais tias: yog tias koj xav tau ntau qhov ntxiv, koj yuav tsum tau txaus siab rau plhaub tawm nyiaj ntau dua

• Lub suab nrov thiab cuam tshuam (suab nrov = cov khoom cuav uas ua rau koj lub cim jagged hloov pauv tsis cuam tshuam txog kev cuam tshuam = tsis yog hom, sinusoidal cuav los ntawm cov cim nyob ib sab ntawm lub xov tooj cua yoj, thiab lwm yam) plague txhua lub cim ntsuas los ntawm lub neej txhua hnub.

  • Qhov nto moo tshaj plaws yog 60Hz cuam tshuam (50Hz yog tias koj nyob hauv Europe thiab tsis muaj nyob hauv Russia vim tias lawv siv DC tsis zoo li AC rau qhov hluav taws xob qhov hluav taws xob …), uas yog hu ua hluav taws xob ntau zaus los ntawm AC hluav taws xob teb ntawm qhov hluav taws xob. Cov kab hluav taws xob nqa AC qhov hluav taws xob siab los ntawm cov tshuab hluav taws xob mus rau thaj chaw nyob, qhov chaw hloov pauv nqis nqis qhov hluav taws xob mus rau tus qauv ~ 120V hauv Asmeskas lub zog hluav taws xob. Qhov hloov pauv hluav taws xob ua rau da dej tas li ntawm 60Hz cuam tshuam hauv peb ib puag ncig, uas cuam tshuam nrog txhua yam cim thiab xav tau lim dej.

  • 60Hz cuam tshuam feem ntau hu ua hom kev cuam tshuam vim tias nws tshwm nyob rau hauv ob qho ntawm koj cov tswv yim (+ thiab -) rau op amps. Tam sim no, op amps muaj qee yam hu ua hom sib thooj tsis lees paub (CMRR) txhawm rau txo cov khoom cuav sib xws, tab sis (kho kuv yog tias kuv ua yuam kev!). Txhawm rau tshem tawm 60Hz, cov lim lim bandstop tuaj yeem siv los xaiv tshem nws los ntawm qhov siv zaus, tab sis tom qab ntawd koj kuj tseem ua rau muaj kev pheej hmoo tshem tawm cov ntaub ntawv tiag. Cov ntaub ntawv zoo tshaj plaws, koj tuaj yeem siv lub lim qis dhau los tsuas yog khaws ntau qhov ntau zaus qis dua 60Hz, yog li txhua yam uas muaj ntau zaus ntau dua raug lim tawm. Qhov ntawd yog qhov kuv tau ua rau EOG: qhov kev cia siab bandwidth ntawm kuv lub teeb liab yog 0-10Hz (tsis quav ntsej qhov muag txav nrawm-tsis xav nrog nws nyob hauv peb qhov kev hloov pauv yooj yim) yog li kuv tshem tawm ntau zaus ntau dua 10Hz nrog lim qis.

    • 60Hz tuaj yeem ua tsis ncaj rau peb cov cim ntawm kev sib txuas ua haujlwm tau thiab kev sib koom ua ke. Kev sib txuas ua ke (nyeem ntawm lub capacitors ntawm no) tshwm sim thaum huab cua ua haujlwm raws li dielectric rau AC cov cim qhia kom ua ntawm nruab nrab ntawm cov khoom sib txuas. Kev sib koom ua ke los ntawm Faraday txoj cai thaum koj khiav tam sim no hauv thaj chaw sib nqus. Muaj ntau ntau yam kev dag kom kov yeej kev sib koom tes: koj tuaj yeem siv daim thaiv npog av raws li kev sib tw ntawm Faraday tawb, piv txwv. Twisting/braiding xov hlau thaum ua tau txo qis thaj tsam muaj rau kev sib txuas inductive los cuam tshuam. Ua kom cov xov hlau luv thiab txo qhov dav ntawm koj lub Circuit Court kuj tseem muaj qhov cuam tshuam zoo ib yam. Kev cia siab rau lub roj teeb lub zog rau op amp txoj kab uas tau tawm tsam los ntsaws rau lub qhov hluav taws xob kuj tseem pab tau vim tias cov roj teeb muab DC qhov chaw uas tsis muaj qhov sinusoidal oscillation. Nyeem ntau ntxiv ntawm no!

    • Cov lim qis dhau kuj tau tshem ntau lub suab nrov, vim tias lub suab nrov tsis zoo yog sawv cev los ntawm cov zaus. Ntau lub suab nrov yog suab nrov dawb, txhais tau tias muaj suab nrov nyob rau txhua zaus, yog li txwv koj lub teeb liab bandwidth ntau li ntau tau los pab txo qhov ntau npaum li cas ntawm cov suab nrov tam sim no hauv koj lub teeb liab.

      Qee qhov lim qis dhau hu ua anti-aliasing lim vim tias lawv tiv thaiv cov npe tsis raug: thaum cov sinusoids raug kuaj, lawv yuav raug kuaj raws li qhov sib txawv ntau ces lawv yeej yog. Koj yuav tsum nco ntsoov ua raws Nyquist tus qauv theorem (piv txwv cov cim ntawm 2x ntau dua: xav tau kev ntsuas ntau ntawm> 2Hz rau qhov xav tau 1Hz sine wave, thiab lwm yam). Hauv qhov xwm txheej EOG no, Kuv tsis tas yuav txhawj xeeb txog Nyquist vim tias kuv lub teeb liab tau cia siab tias yuav nyob hauv 10Hz ntau, thiab kuv li Arduino ADC cov qauv ntawm 10kHz - ntau dua li nrawm txaus rau txhua yam

  • Kuj tseem muaj cov txuj ci me me kom tshem suab nrov. Ib qho yog siv lub hnub qub hauv av yog li txhua qhov ntawm koj cov khoom siv hluav taws xob muaj qhov siv tib yam nkaus. Txwv tsis pub, dab tsi ib feem hu ua "hauv av" yuav txawv ntawm lwm qhov vim muaj kev tiv thaiv me ntsis hauv cov xov hlau, uas ntxiv rau qhov tsis sib xws. Soldering rau protoboard es tsis txhob lo nrog cov laug cam kuj tseem txo qee lub suab nrov thiab tsim kev sib txuas ruaj ntseg uas koj tuaj yeem ntseeg tau yam tsis zoo rau kev nias-haum tso.

Muaj ntau txoj hauv kev los txwv lub suab nrov thiab cuam tshuam (saib ntawm no thiab ntawm no), tab sis koj tuaj yeem kawm chav kawm ntawm qhov ntawd lossis Google kom paub ntau ntxiv: cia peb txav mus rau qhov Circuit tiag!

Kauj Ruam 4: Lub Circuit Court Ua Haujlwm Li Cas

Tsis txhob ntshai los ntawm daim duab qhia chaw: ntawm no yog qhov ntxhib ntxhib ntawm txhua yam ua haujlwm li cas: (xa rov qab mus rau kauj ruam dhau los rau qee qhov kev piav qhia ib yam nkaus)

• Ntawm sab laug peb muaj cov electrodes. Ib qho yog txuas rau ntawm lub tuam tsev sab laug, lwm qhov ntawm lub tuam tsev sab xis, thiab qhov hluav taws xob thib peb tau muab pov rau hauv pliaj. Qhov av hauv av ruaj khov lub teeb liab yog li muaj tsawg dua kev txav, thiab nws tseem tau tshem qee yam ntawm 60Hz cuam tshuam.
• Tom ntej no yog ntsuas qhov ntsuas. Rov qab ob kauj ruam rau kev piav qhia ntawm nws ua dab tsi los tsim qhov sib txawv ntawm qhov hluav taws xob. Qhov sib npaug rau kev hloov pauv qhov nce ntawm amp yog nyob rau nplooj 7 ntawm cov ntaub ntawv [G = 1+ (50kOhm/Rg) qhov twg Rg txuas nrog ntawm amp tus pin 1 thiab 8]. Txog kuv qhov kev sib tw, kuv hloov kho kom tau txais 500 los ntawm kev siv Rg = 100Ohm.
• Tom qab ntsuas qhov ntsuas tawm 500x qhov sib txawv ntawm qhov sib txawv ntawm qhov sib txawv, muaj thawj-xaj RC qis dhau lim, uas suav nrog tus tiv thaiv R_filter thiab capacitor C_filter. Cov lim qis dhau tiv thaiv kev tiv thaiv tsis raug cai (tsis muaj kev txhawj xeeb rau kuv txawm hais tias los ntawm Nyquist, Kuv yuav tsum ua piv txwv tsawg kawg 20Hz rau qhov xav tau 10Hz bandwidth, thiab Arduino ADC cov qauv ntawm 10kHz-ntau dua li txaus) thiab tseem txiav tawm suab nrov ntawm txhua zaus uas kuv tsis xav tau. RC system ua haujlwm vim tias cov khoom siv tso cai rau siv ntau zaus los ntawm kev yooj yim tab sis cuam tshuam qis dua (impedance Z = 1/(2*pi*f)), thiab tsim qhov sib faib hluav taws xob nrog qhov hluav taws xob hla lub capacitor ua rau lub lim uas tsuas tso cai qis dua los ntawm [txiav tawm rau 3dB kev siv yog tswj hwm los ntawm cov mis f_c = 1/(2*pi*RC)]. Kuv hloov kho kuv lub lim R thiab C qhov tseem ceeb kom txiav tawm cov cim siab dua ~ 10Hz vim tias lub teeb liab lom rau EOGs xav tau nyob hauv thaj tsam ntawd. Thaum xub thawj kuv txiav tawm tom qab 20Hz, tab sis tom qab kev sim 10Hz ua haujlwm ib yam nkaus, yog li kuv tau mus nrog cov bandwidth me dua (bandwidth me dua yog qhov zoo dua los txiav tawm txhua yam tsis tsim nyog, tsuas yog qhov xwm txheej).
• Nrog rau qhov teeb meem lim dej no, Kuv ntsuas cov zis nrog oscilloscope kom pom kuv qhov ntau ntawm qhov muaj txiaj ntsig los ntawm kev saib sab laug thiab sab xis (ob qhov dhau ntawm kuv qhov ntau). Qhov ntawd tau txais kuv txog 2-4V (vim tias qhov ntsuas qhov ntsuas tau nce 500x rau thaj tsam ntawm ~ 4-8mV), thaum kuv lub hom phiaj yog 5V (tag nrho ntawm Arduino ADC). Qhov no sib txawv ntau yam (raws li tus neeg tau ntxuav cov tawv nqaij ua ntej, thiab lwm yam) yog li kuv tsis xav kom muaj qhov nce ntau nrog kuv qhov thib ob uas tsis hloov pauv amp. Kuv xaus kev kho nws kom tau txais txiaj ntsig tsuas yog 1.3 (kho R1 thiab R2 hauv Circuit vim tias nce ntawm amp = 1+R2/R1). Koj yuav tsum tau nthuav koj tus kheej cov zis thiab hloov kho los ntawm qhov ntawd kom koj tsis txhob hla 5V! Tsis txhob cia li siv kuv tus resistor qhov tseem ceeb.
• Tam sim no lub teeb liab no tuaj yeem nkag mus rau Arduino analog pin rau nyeem tab sis Arduino ADC tsis lees txais cov tswv yim tsis zoo! Koj yuav tsum tau hloov koj lub teeb liab kom qhov ntau yog 0-5V tsis zoo li -2.5V txog 2.5V. Ib txoj hauv kev los kho qhov no yog txhawm rau txuas hauv av ntawm koj lub rooj tsav xwm hauv Circuit rau 3.3V tus pin ntawm Arduino: qhov no hloov koj lub teeb liab los ntawm 3.3V (ntau dua 2.5V pom zoo tab sis nws ua haujlwm). Kuv qhov ntau yeej yeej yeej yog li kuv tau tsim qhov sib txawv ntawm qhov ntsuas hluav taws xob: txoj kev ntawd, Kuv tuaj yeem tig lub hwj chim ntsuas hluav taws xob kom nruab nrab qhov nruab nrab rau 0-5V. Nws yog qhov tseem ceeb sib txawv qhov sib faib hluav taws xob siv lub +/- 9V fais fab txuas kom kuv tuaj yeem txuas cov kab hluav taws xob hauv av rau ib qho txiaj ntsig ntawm -9 txog 9V thiab yog li hloov kuv lub teeb liab nce lossis nqis 9V.

Kauj Ruam 5: Xaiv Cheebtsam thiab Tus Nqi

Nrog cov lus piav qhia hauv Circuit Court, peb yuav xaiv qhov twg (electrode, op amp) los siv?

• Raws li lub ntsuas hluav taws xob, cov khoom siv hluav taws xob gel muaj cov tswv yim siab impedance thiab qhov tso tawm tsawg impedance: dab tsi qhov tseem ceeb txhais tau tias yog tam sim no tuaj yeem yooj yim hla nqes mus rau qhov seem ntawm lub Circuit Court (tso zis tsawg impedance) tab sis yuav muaj teeb meem hla dhau ntws rov qab mus rau koj lub tuam tsev (siab input impedance). Qhov no tiv thaiv tus neeg siv los ntawm kev raug mob los ntawm ib qho siab tam sim no lossis qhov hluav taws xob hauv seem ntawm koj qhov kev sib tw; qhov tseeb, ntau lub tshuab muaj qee yam hu ua tiv thaiv tus neeg mob tiv thaiv kev tiv thaiv ntxiv, ib yam nkaus.

  • Muaj ntau hom sib txawv electrode muaj nyob. Cov neeg feem ntau hais qhia Ag/AgCl cov kua nplaum zoo rau siv hauv EKG/EOG/lwm yam ntawv thov. Nrog rau qhov no hauv siab, koj yuav tsum saib mus rau qhov tsis kam ntawm cov hluav taws xob no (mus ob kauj ruam rov qab rau kuv cov ntawv ntawm daim tawv nqaij tsis kam) thiab phim nws mus rau lub suab tsis kam (suab nrov hauv V/sqrt (Hz) faib los ntawm lub suab nrov tam sim no hauv A/sqrt (Hz) - saib cov ntaub ntawv ntawm op amps) ntawm koj op amps - uas yog qhov koj xaiv qhov ntsuas qhov ntsuas qhov tseeb rau koj li cas. Qhov no hu ua sib txuam suab nrov, thiab kev piav qhia txog vim li cas sib cuam tshuam qhov cuam tshuam Rs rau lub suab tsis kam Rn ua haujlwm tuaj yeem pom online zoo li ntawm no. Rau kuv INA111 uas kuv tau xaiv, Rn tuaj yeem suav nrog siv lub suab nrov nrov thiab suab nrov tam sim no ntawm cov ntaub ntawv (screenshot saum toj no).

    • Muaj PLENTY ntawm kab lus ntsuas kev ua haujlwm hluav taws xob, thiab tsis muaj ib qho hluav taws xob zoo tshaj plaws rau txhua lub hom phiaj: sim ntawm no, piv txwv. Impedance kuj tseem hloov pauv rau cov bandwidth sib txawv raws li pom hauv op amp cov ntaub ntawv (qee cov ntaub ntawv yuav muaj qhov nkhaus lossis cov ntxhuav ntawm ntau zaus). Ua koj qhov kev tshawb fawb tab sis nco ntsoov khaws koj lub hnab nyiaj hauv siab. Nws yog qhov zoo kom paub tias cov electrodes/op amps twg zoo tshaj, tab sis nws tsis siv yog tias koj tsis tuaj yeem them taus. Koj yuav xav tau ~ 50 qhov hluav taws xob tsawg kawg rau kev sim, tsis yog 3 zaug rau siv ib zaug.

      • Rau kev pom lub suab nrov sib xws, tsis tsuas yog yuav tsum Rn ~ = Rs: koj kuj xav tau lub suab nrov nrov * suab nrov tam sim no (Pn) kom qis li sai tau. Qhov no suav tias yog qhov tseem ceeb dua li ua Rn ~ = Rs vim tias koj tuaj yeem kho Rs thiab Rn los ntawm kev siv cov hloov pauv yog tias tsim nyog.

        Ceev faj nrog cov hloov pauv (kho kuv yog tias tsis raug): lawv tuaj yeem ua rau me ntsis loj thiab yog li tsis pom zoo rau cov cuab yeej uas xav tau me me. Lawv kuj tsim cov cua sov kom sov lub dab dej lossis qhov cua nkag tau zoo yog qhov tsim nyog

      • Lub suab nrov sib phim rau koj thawj zaug amp; qhov thib ob amp tsis cuam tshuam ntau npaum li cas, yog li txhua op amp yuav ua.

Kauj Ruam 6: Tsim Circuit Court

Siv daim duab fritzing saum toj no los tsim lub Circuit Court (daim ntawv theej thib ob qhia txog txhua feem hais txog hauv daim duab kab lus los ntawm cov kauj ruam dhau los). Yog tias koj xav tau kev pab txheeb xyuas LEDs hauv daim duab, siv tus lej ntsuas tus lej tiv thaiv tus lej, tab sis Rg ntawm qhov ntsuas qhov ntsuas yog 100Ohm, R_filter yog 1.5MOhm, C_filter yog 0.1uF, R1 ntawm qhov tsis hloov pauv amp yog 10kOhm, R2 yog 33kOhm, thiab tus tiv thaiv rau lub zog ntsuas hluav taws xob yog 1kOhm (potentiometer txawv ntawm 0 txog 20kOhm). Nco ntsoov hloov koj qhov kev tiv thaiv tus nqi raws li xav tau los kho kom tau txais txiaj ntsig!

Kho kom raug: muaj qhov ua yuam kev hauv qhov offset av. Rho tawm sab laug dub xaim. Tus tiv thaiv yuav tsum tau txuas nrog xaim liab mus rau txoj kev tsheb nqaj hlau raws li qhia tab sis kuj rau tus pin thib ob, tsis yog thawj zaug, ntawm lub hwj chim. Thawj tus pin ntawm lub hwj chim yuav tsum txuas nrog 5V tus pin ntawm Arduino. Txiv kab ntxwv hlau uas yog qhov av offset yuav tsum txuas nrog tus pin thib ob, tsis yog thawj zaug.

Kuv tau tham txog qhov offset av ntau. Hauv daim duab koj tuaj yeem pom tias Arduino av tau qhia ua txuas nrog rau hauv av ntawm lub khob cij. Qhov ntawd yog qhov xwm txheej uas koj tsis tas yuav hloov koj li av. Yog tias koj lub teeb liab tawm ntawm qhov ntau thiab koj yuav tsum tau hloov pauv koj hauv av, xub sim txuas Arduino hauv av mus rau 3.3V tus pin ntawm Arduino thiab saib koj lub teeb liab. Txwv tsis pub sim nqes cov txiv kab ntxwv nyob hauv lub hwj chim teeb tsa (offset av) mus rau GND tus pin ntawm Arduino.

CEEB TOOM CEEB TOOM: tsis txhob khaws cov roj teeb thaum siv cov laug, thiab TSIS TXHOB TSIS tso lossis muab roj teeb tso rau tom qab. Koj lub voj voog yuav pib haus luam yeeb, lub tshuab hluav taws xob yuav tshuab, thiab lub khob cij yuav puas ib yam nkaus. Raws li txoj cai ntawm tus ntiv tes xoo, tsuas yog siv cov roj teeb thaum koj xav siv lub Circuit Court; txwv tsis pub, tshem lawv tawm (ntxiv qhov hloov pauv kom yooj yim txuas lub roj teeb yuav yog lub tswv yim zoo ib yam).

Nco ntsoov tias koj yuav tsum tsim cov kab hluav taws xob ib thooj (txheeb xyuas txhua theem!) Thawj theem los tshuaj xyuas yog ntsuas qhov ntsuas: txuas txhua txoj kab (kab laug sab hauv lub roj teeb tuav), Rg, thiab lwm yam thiab siv oscilloscope ntawm tus pin tso tawm. Txhawm rau pib, siv lub tshuab hluav taws xob ua haujlwm nrog 1Hz sine wave nrog 5mV qhov dav (lossis qis tshaj koj lub tshuab hluav taws xob yuav mus). Qhov no tsuas yog txhawm rau txheeb xyuas qhov ntsuas qhov ntsuas amp ua haujlwm tau zoo, thiab koj Rg tau muab koj lub hom phiaj nce.

Tom ntej no, txheeb xyuas koj cov lim qis. Ntxiv qhov ntawd ntawm qhov Circuit Court thiab txheeb xyuas koj cov waveform: nws yuav tsum zoo ib yam nkaus tab sis tsis muaj suab nrov (jagged - saib ob daim duab kawg saum toj no). Cia peb sojntsuam koj qhov tso tawm zaum kawg nrog oscilloscope nrog koj cov electrodes tsis txhob siv lub tshuab hluav taws xob tam sim no …

Kauj Ruam 7: Kuaj Circuit Court nrog Tib Neeg

Ib zaug ntxiv, tso hluav taws xob tso rau ntawm koj lub tuam tsev sab laug thiab sab xis, thiab txuas cov xov hlau hauv av rau hluav taws xob ntawm koj lub hauv pliaj. Tsuas yog tom qab ntawd koj yuav tsum ntxiv roj teeb - yog tias muaj qhov tingling tshwm sim, tshem tawm tam sim thiab txheeb xyuas ob zaug sib txuas !!! Tam sim no txheeb xyuas koj qhov ntau ntawm qhov muaj txiaj ntsig thaum koj saib sab laug vs. sab xis thiab kho R1/R2 ntawm qhov tsis hloov pauv amp, raws li tau piav qhia ob kauj ruam dhau los-nco ntsoov tias lub hom phiaj yog 5V ntau yam! Saib cov duab saum toj no txhawm rau sau tseg saib dab tsi.

Thaum koj zoo siab nrog txhua qhov kev tiv thaiv qhov tseem ceeb, muab txhua yam tso rau hauv lub qhov rooj tiv thaiv. Kev siv tshuaj tsis yog qhov tsim nyog, tab sis nws muab kev ruaj ntseg ntau dua qhov yooj yim nias haum cov pob qij txha thiab tshem tawm qhov tsis paub tseeb ntawm Circuit tsis ua haujlwm yooj yim vim tias koj tsis nias lawv rau hauv lub khob cij tawv txaus.

Kauj Ruam 8: Arduino Code

Txhua tus lej txuas hauv qab ntawm cov kauj ruam no!

Tam sim no koj muaj 5V ntau yam, koj yuav tsum paub tseeb tias nws poob qis hauv 0-5V hloov -1V rau 4V, thiab lwm yam. Txuas ib qho av rau 3.3V tus pin ntawm Arduino lossis txuas qhov hluav taws xob hauv av (txiv kab ntxwv hlau saum toj no) mus rau cov tsheb nqaj hlau hauv av thiab tom qab ntawd txuas cov hlau los ntawm txoj kev tsheb nqaj hlau hauv av mus rau GND tus pin ntawm Arduino (qhov no yog hloov lub teeb liab nce lossis nqis kom koj poob qis hauv 0-5V ntau yam). Koj yuav tsum tau ua si ib puag ncig: tsis txhob hnov qab nthuav koj cov txiaj ntsig thaum twg tsis paub meej!

Tam sim no rau kev ntsuas ntsuas: koj xav kom lub teeb hloov xim rau qhov muag sib txawv (saib mus rau sab laug vs. tsis deb li deb..). Txog qhov uas koj xav tau qhov tseem ceeb thiab ntau yam: khiav EOG-calibration-numbers.ino rau Arduino nrog txhua yam sib txuas kom raug (ua tiav kev sib txuas mus rau Arduino thiab neopixel raws li kuv daim duab fritzing). Tsis yog qhov tsim nyog, tab sis kuj tseem siv tus lej bioe.py kuv muaj - qhov no yuav tso tawm cov ntawv xa mus rau koj lub desktop yog li koj tuaj yeem sau txhua qhov txiaj ntsig raws li koj saib sab laug lossis sab xis (sej code tau hloov pauv los ntawm qhov piv txwv no). Kuv ua li cas qhov no tau saib sab laug rau 8 ntaus, tom qab ntawd sab xis, tom qab ntawd rov qab thiab rov ua qhov nruab nrab tom qab (saib output_2.pdf rau ib lub cav kuv khaws). Nias ctrl+C kom yuam kev tawm thaum koj txaus siab. Siv cov txiaj ntsig ntawd, tom qab ntawd koj tuaj yeem kho qhov kev ua yeeb yaj kiab 'kab hauv kuv BioE101_EOG-neopixel.ino code. Rau kuv, Kuv muaj cov duab zaj sawv thaum kuv ntsia ncaj nraim rau tom ntej, xiav rau sab laug deb, ntsuab rau sab laug me ntsis, ntshav liab rau sab xis, thiab liab rau sab xis.

Kauj Ruam 9: Cov Kauj Ruam Yav Tom Ntej

Voila; qee yam uas koj tuaj yeem tswj hwm nrog koj lub qhov muag. Muaj ntau ntau los ua kom zoo ua ntej nws tuaj yeem ua nws txoj kev mus rau tsev kho mob, tab sis yog rau lwm hnub: cov hauv paus ntsiab lus yam tsawg kawg yog nkag siab yooj yim tam sim no. Ib yam uas kuv xav rov qab mus thiab hloov pauv yog kho kuv qhov nce mus rau 500 rau qhov ntsuas qhov ntsuas: saib rov qab, uas yog zaum ntau dua0 vim tias kuv lub teeb liab tom qab yog 2-4V twb tau thiab kuv muaj lub sijhawm nyuaj siv qhov tsis hloov pauv amp los kho kuv qhov ntau yam zoo kawg nkaus …

Nws nyuaj rau kom tau txais qhov sib xws vim tias lub teeb liab hloov pauv ntau rau cov xwm txheej sib txawv:

• tus neeg sib txawv
• teeb pom kev zoo
• kev npaj tawv nqaij (gel, ntxhua khaub ncaws, thiab lwm yam)

tab sis txawm li ntawd los, Kuv txaus siab heev nrog kuv qhov vis dis aus kawg ntawm qhov ua tau zoo (coj los ntawm 3AM vim tias yog thaum txhua yam zoo nkauj pib ua haujlwm).

Kuv paub tias ntau qhov kev qhia no tuaj yeem zoo li tsis meej pem (yog, txoj kev kawm nkhaus nyuaj rau kuv ib yam) yog li thov koj xav nug cov lus nug hauv qab no thiab kuv yuav ua qhov zoo tshaj los teb. Txaus siab rau!

Khiav Tawm Hauv Qhov Tsis Sib Tw Sib Tw