{"id":61486,"date":"2023-04-21T13:44:03","date_gmt":"2023-04-21T18:44:03","guid":{"rendered":"https:\/\/www.bjultrasonic.com\/diy-ultrasonic-microphone\/"},"modified":"2025-01-27T06:04:30","modified_gmt":"2025-01-27T11:04:30","slug":"diy-ultrasonic-microphone","status":"publish","type":"post","link":"https:\/\/www.bjultrasonic.com\/cs\/diy-ultrasonic-microphone\/","title":{"rendered":"DIY ultrazvukov\u00fd mikrofon: N\u00e1vod krok za krokem"},"content":{"rendered":"

Vytvo\u0159en\u00ed vlastn\u00edho ultrazvukov\u00e9ho mikrofonu je n\u00e1ro\u010dn\u00fd, ale z\u00e1rove\u0148 fascinuj\u00edc\u00ed projekt, kter\u00fd kombinuje elektroniku, akustiku a programov\u00e1n\u00ed. Tento \u010dl\u00e1nek se zam\u011b\u0159\u00ed na kl\u00ed\u010dov\u00e9 aspekty konstrukce takov\u00e9ho za\u0159\u00edzen\u00ed, od v\u00fdb\u011bru komponent a\u017e po z\u00e1kladn\u00ed kalibraci. \u00dasp\u011b\u0161n\u00e1 realizace z\u00e1vis\u00ed na pe\u010dliv\u00e9m pl\u00e1nov\u00e1n\u00ed a precizn\u00ed pr\u00e1ci.<\/p>\n

V\u00fdb\u011br piezoelektrick\u00e9ho sn\u00edma\u010de<\/p>\n

Srdcem ultrazvukov\u00e9ho mikrofonu je piezoelektrick\u00fd sn\u00edma\u010d, kter\u00fd p\u0159ev\u00e1d\u00ed mechanick\u00e9 vibrace (zvukov\u00e9 vlny) na elektrick\u00fd sign\u00e1l. Na trhu je dostupn\u00e1 \u0161irok\u00e1 \u0161k\u00e1la sn\u00edma\u010d\u016f s r\u016fzn\u00fdmi frekven\u010dn\u00edmi charakteristikami a citlivost\u00ed. Pro DIY projekt je vhodn\u00e9 zvolit sn\u00edma\u010d s frekven\u010dn\u00edm rozsahem zahrnuj\u00edc\u00edm po\u017eadovanou ultrazvukovou oblast, typicky v rozmez\u00ed 20 kHz a\u017e 100 kHz. Je d\u016fle\u017eit\u00e9 si uv\u011bdomit, \u017ee citlivost sn\u00edma\u010de ovliv\u0148uje kvalitu zaznamenan\u00e9ho sign\u00e1lu. Vy\u0161\u0161\u00ed citlivost znamen\u00e1 lep\u0161\u00ed detekci slab\u00fdch zvuk\u016f, ale tak\u00e9 v\u011bt\u0161\u00ed n\u00e1chylnost k \u0161umu.<\/p>\n\n\n\n\n\n\n\n
Parametr<\/th>\nHodnota (P\u0159\u00edklad)<\/th>\nPozn\u00e1mka<\/th>\n<\/tr>\n<\/thead>\n
Frekven\u010dn\u00ed rozsah<\/td>\n20 kHz – 100 kHz<\/td>\nVolba z\u00e1vis\u00ed na zam\u00fd\u0161len\u00e9 aplikaci<\/td>\n<\/tr>\n
Citlivost<\/td>\n-50 dBV<\/td>\nVy\u0161\u0161\u00ed citlivost = lep\u0161\u00ed detekce, ale v\u00edce \u0161umu<\/td>\n<\/tr>\n
Impedan\u010dn\u00ed impedance<\/td>\n10 k\u03a9<\/td>\nD\u016fle\u017eit\u00e9 pro spr\u00e1vn\u00e9 zapojen\u00ed do obvodu<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

P\u0159edzesilova\u010d sign\u00e1lu<\/p>\n

Sign\u00e1l z piezoelektrick\u00e9ho sn\u00edma\u010de je typicky velmi slab\u00fd a vy\u017eaduje zes\u00edlen\u00ed p\u0159ed dal\u0161\u00edm zpracov\u00e1n\u00edm. P\u0159edzesilova\u010d by m\u011bl m\u00edt n\u00edzk\u00fd \u0161um a vysokou vstupn\u00ed impedanci, aby co nejm\u00e9n\u011b ovlivnil sign\u00e1l ze sn\u00edma\u010de. Pro konstrukci p\u0159edzesilova\u010de lze vyu\u017e\u00edt opera\u010dn\u00ed zesilova\u010de (op-amp), kter\u00e9 jsou cenov\u011b dostupn\u00e9 a snadno se s nimi pracuje. Je d\u016fle\u017eit\u00e9 db\u00e1t na spr\u00e1vn\u00e9 nap\u00e1jen\u00ed a uzemn\u011bn\u00ed, aby se minimalizovalo ru\u0161en\u00ed.<\/p>\n

Zpracov\u00e1n\u00ed a digitalizace sign\u00e1lu<\/p>\n

Zes\u00edlen\u00fd analogov\u00fd sign\u00e1l je nutn\u00e9 digitalizovat pro dal\u0161\u00ed zpracov\u00e1n\u00ed v po\u010d\u00edta\u010di. K tomu lze pou\u017e\u00edt analogov\u011b-digit\u00e1ln\u00ed p\u0159evodn\u00edk (ADC). Mnoho zvukov\u00fdch karet disponuje vestav\u011bn\u00fdm ADC, ale pro vy\u0161\u0161\u00ed p\u0159esnost a flexibilitu je mo\u017en\u00e9 pou\u017e\u00edt extern\u00ed ADC s vy\u0161\u0161\u00ed vzorkovac\u00ed frekvenc\u00ed. Vzorkovac\u00ed frekvence by m\u011bla b\u00fdt alespo\u0148 dvojn\u00e1sobek maxim\u00e1ln\u00ed frekvence ultrazvukov\u00e9ho sign\u00e1lu (Nyquist-Shannon\u016fv teor\u00e9m).<\/p>\n

Kalibrace a testov\u00e1n\u00ed<\/p>\n

Po sestaven\u00ed ultrazvukov\u00e9ho mikrofonu je nezbytn\u00e1 kalibrace a testov\u00e1n\u00ed. K tomu lze vyu\u017e\u00edt kalibra\u010dn\u00ed zdroj ultrazvuku, nap\u0159\u00edklad ultrazvukov\u00fd gener\u00e1tor. Kalibrace se zam\u011b\u0159uje na ov\u011b\u0159en\u00ed linearity a citlivosti mikrofonu v cel\u00e9m frekven\u010dn\u00edm rozsahu. Testov\u00e1n\u00ed zahrnuje m\u011b\u0159en\u00ed \u0161umu a zkreslen\u00ed sign\u00e1lu. Kvalitn\u00ed kalibrace je kl\u00ed\u010dov\u00e1 pro z\u00edsk\u00e1n\u00ed spolehliv\u00fdch m\u011b\u0159en\u00ed.<\/p>\n

Pouzdro a ochrana<\/p>\n

Pro ochranu citliv\u00fdch komponent a zlep\u0161en\u00ed akustick\u00fdch vlastnost\u00ed je vhodn\u00e9 um\u00edstit cel\u00fd syst\u00e9m do vhodn\u00e9ho pouzdra. Materi\u00e1l pouzdra by m\u011bl b\u00fdt pevn\u00fd a z\u00e1rove\u0148 dostate\u010dn\u011b tlumen\u00fd, aby se minimalizovaly vibrace a ru\u0161en\u00ed z okol\u00ed.<\/p>\n

Vytvo\u0159en\u00ed funk\u010dn\u00edho ultrazvukov\u00e9ho mikrofonu vy\u017eaduje ur\u010dit\u00e9 znalosti elektroniky a programov\u00e1n\u00ed. P\u0159esto je to uskute\u010dniteln\u00fd projekt pro zku\u0161en\u011bj\u0161\u00ed kutily, kter\u00fd nab\u00edz\u00ed mo\u017enost prozkoumat fascinuj\u00edc\u00ed sv\u011bt ultrazvuku. Spr\u00e1vn\u00fd v\u00fdb\u011br komponent a pe\u010dliv\u00e1 pr\u00e1ce jsou kl\u00ed\u010dem k \u00fasp\u011bchu. Na z\u00e1v\u011br je d\u016fle\u017eit\u00e9 zd\u016fraznit, \u017ee bezpe\u010dnost pr\u00e1ce s elektronikou je na prvn\u00edm m\u00edst\u011b.<\/p>\n","protected":false},"excerpt":{"rendered":"

Vytvo\u0159en\u00ed vlastn\u00edho ultrazvukov\u00e9ho mikrofonu je n\u00e1ro\u010dn\u00fd, ale z\u00e1rove\u0148 fascinuj\u00edc\u00ed projekt, kter\u00fd kombinuje elektroniku, akustiku a programov\u00e1n\u00ed. Tento \u010dl\u00e1nek se zam\u011b\u0159\u00ed na kl\u00ed\u010dov\u00e9 aspekty konstrukce takov\u00e9ho za\u0159\u00edzen\u00ed, od v\u00fdb\u011bru komponent a\u017e po z\u00e1kladn\u00ed kalibraci. \u00dasp\u011b\u0161n\u00e1 realizace z\u00e1vis\u00ed na pe\u010dliv\u00e9m pl\u00e1nov\u00e1n\u00ed a precizn\u00ed pr\u00e1ci. V\u00fdb\u011br piezoelektrick\u00e9ho sn\u00edma\u010de Srdcem ultrazvukov\u00e9ho mikrofonu je piezoelektrick\u00fd sn\u00edma\u010d, kter\u00fd p\u0159ev\u00e1d\u00ed mechanick\u00e9 vibrace<\/p>\n","protected":false},"author":1,"featured_media":26750,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6415],"tags":[],"class_list":["post-61486","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","prodpage-classic"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/61486","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/comments?post=61486"}],"version-history":[{"count":0,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/61486\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media\/26750"}],"wp:attachment":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media?parent=61486"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/categories?post=61486"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/tags?post=61486"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}