{"id":923,"date":"2023-04-07T19:45:06","date_gmt":"2023-04-08T02:45:06","guid":{"rendered":"https:\/\/unixwizardry.com\/?p=923"},"modified":"2024-08-17T20:32:04","modified_gmt":"2024-08-18T03:32:04","slug":"metone-anemometer","status":"publish","type":"post","link":"https:\/\/unixwizardry.com\/index.php\/2023\/04\/07\/metone-anemometer\/","title":{"rendered":"MetOne Anemometer"},"content":{"rendered":"\t\t
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\u00a0Now, on to the anemometer testing.\u00a0 I am currently trying to use a hardware debounce circuit (shown) and it WAS working and counting the pulses from the reed switch pretty consistently.\u00a0<\/span><\/p>

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Works well, but 100uS time constant.<\/figcaption><\/figure>

But it\u2019s weird that a shorter RC time constant debounce circuit works better than a longer one.\u00a0 The RC time constant that seems to work better is 100 uS; if I change the capacitor to, say, a 100nF (1ms time contstant), then I get more contact bounce interrupts…weird Not what I would expect. I was using a NO (Normally Open) pushbutton switch, not a reed switch so maybe that\u2019s the issue. So, I found a small reed switch and tested with that. The switch is about the same size as the one in the 034B anemometer, I think, so the bounce time should be about the same. Below is a pic from my scope the switch bounce. After numerous activations of the switch using a small magnet I found the maximum bounce time to be no more than 300 uSec (microseconds). I am sorta puzzled why a time constant of 100 uSec works better than, say, 300 uSec. Most of the time the bounce time was like 100 uSec, but occasionally it would be much more but I never saw anything over 300 uSec.\u00a0 So now I’m experimenting with software debounce, an example of which I found\u00a0on Particle.IO forum<\/a> that appears to work really well.\u00a0 Better than a hardware debounce scheme, but I might try using both methods.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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\u00a0Now, on to the anemometer testing.\u00a0 I am currently trying to use a hardware debounce circuit (shown) and it WAS working and […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[38],"tags":[],"class_list":["post-923","post","type-post","status-publish","format-standard","hentry","category-weather-instruments"],"_links":{"self":[{"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/posts\/923","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/comments?post=923"}],"version-history":[{"count":87,"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/posts\/923\/revisions"}],"predecessor-version":[{"id":1271,"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/posts\/923\/revisions\/1271"}],"wp:attachment":[{"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/media?parent=923"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/categories?post=923"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unixwizardry.com\/index.php\/wp-json\/wp\/v2\/tags?post=923"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}