{"id":247,"date":"2014-06-04T20:43:56","date_gmt":"2014-06-04T20:43:56","guid":{"rendered":"http:\/\/www.thinkering.de\/cms\/?p=247"},"modified":"2017-02-20T08:22:43","modified_gmt":"2017-02-20T08:22:43","slug":"hydrostatic-pressure-sensor","status":"publish","type":"post","link":"http:\/\/www.thinkering.de\/cms\/?p=247","title":{"rendered":"Hydrostatic Pressure Sensor"},"content":{"rendered":"<p> I&#8217;ve recently found a single-use medical grade pressure sensor, as used in invasive catheter blood pressure measurements in critical care medicine.<br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\nIt has got 4 output terminals as you can see in the picture below where one can simply insert small 1mm nails&#8230;<br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<a href=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-sensor-top.jpg\"><img loading=\"lazy\" src=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-sensor-top-300x225.jpg\" alt=\"pressure sensor top\" width=\"300\" height=\"225\" class=\"alignnone size-medium wp-image-250\" srcset=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-sensor-top-300x225.jpg 300w, http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-sensor-top-1024x768.jpg 1024w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\nThe internal configuration seems to be a Wheatstone Bridge and therefore it has to deliver an analog output. So some measurements of the resistances between the terminals were made which quickly led to the following test setup:<br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<a href=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/Pressure-Sensor.jpg\"><img loading=\"lazy\" src=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/Pressure-Sensor-300x259.jpg\" alt=\"Pressure Sensor\" width=\"300\" height=\"259\" class=\"alignnone size-medium wp-image-248\" srcset=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/Pressure-Sensor-300x259.jpg 300w, http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/Pressure-Sensor.jpg 553w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<a href=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-test-setup.jpg\"><img loading=\"lazy\" src=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-test-setup-300x225.jpg\" alt=\"pressure test setup\" width=\"300\" height=\"225\" class=\"alignnone size-medium wp-image-251\" srcset=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-test-setup-300x225.jpg 300w, http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/pressure-test-setup-1024x768.jpg 1024w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\nWith 7.2V connected to the sensor the amplitude of the output voltage is at about 0.1V<br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<iframe width=\"560\" height=\"315\" src=\"\/\/www.youtube.com\/embed\/KNHFky3PsZU?rel=0\" frameborder=\"0\" allowfullscreen><\/iframe><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\nA simple opamp-based differential amplifier was used to amplify the output.<br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<br style=\u201dclear:both;\u201d \/><br \/>\n<a href=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/20121022_234411.jpg\"><img loading=\"lazy\" src=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/20121022_234411-300x225.jpg\" alt=\"20121022_234411\" width=\"300\" height=\"225\" class=\"alignnone size-medium wp-image-249\" srcset=\"http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/20121022_234411-300x225.jpg 300w, http:\/\/www.thinkering.de\/cms\/wp-content\/uploads\/2014\/06\/20121022_234411-1024x768.jpg 1024w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>I&#8217;ve recently found a single-use medical grade pressure sensor, as used in invasive catheter blood pressure measurements in critical care medicine. It has got 4 output terminals as you can see in the picture below where one can simply insert small 1mm nails&#8230; The internal configuration seems to be a Wheatstone Bridge and therefore it &hellip; <a href=\"http:\/\/www.thinkering.de\/cms\/?p=247\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Hydrostatic Pressure Sensor<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[7],"tags":[],"_links":{"self":[{"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=\/wp\/v2\/posts\/247"}],"collection":[{"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=247"}],"version-history":[{"count":5,"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=\/wp\/v2\/posts\/247\/revisions"}],"predecessor-version":[{"id":254,"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=\/wp\/v2\/posts\/247\/revisions\/254"}],"wp:attachment":[{"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=247"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=247"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.thinkering.de\/cms\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=247"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}