tag:blogger.com,1999:blog-38893335957684232.post6314825562738359157..comments2023-01-20T16:43:34.935-08:00Comments on Hardware Hacks: Christmas-tree water-level alertDr. Ayarshttp://www.blogger.com/profile/11192509765516630383noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-38893335957684232.post-59528487367387649992013-01-06T17:34:32.238-08:002013-01-06T17:34:32.238-08:00Great work! I have been looking to do something li...Great work! I have been looking to do something like this and your page has really helped.<br /><br />BTW Don't waste your time trying to appease the moronic Arduino haters. They aren't worth your time.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-33875576607115765162012-11-14T13:07:08.429-08:002012-11-14T13:07:08.429-08:00It may be helpful to understand HOW the capacitive...It may be helpful to understand HOW the capacitive sensor works... water is highly polarizable, so its presence in an electric field lowers the field and thus the voltage between the electrodes. The net effect is that to reach the same voltage as before requires a higher charge, and since Q/V = C the capacitance is higher when water is present.<br /><br />That's about a week and a half of physics lecture in two sentences, so cut to the good part: the capacitance depends on the water level. More water -> higher value of C measured by the arduino.<br /><br />If your sensor is on the outside of the tree's water bowl, then the tree won't affect it much as there's probably a couple inches of water between the electrodes and the tree. The water will dominate the effect. I wouldn't strap the electrodes to the tree, though: the dielectric constant of the tree is uncertain, and variable, and will generally confuse things.<br /><br />Keep in mind, while you're testing this, that the measurement is measuring C not "water". Your hands will change C also, even by just being near the sensor. If you "press the sensor to the outside of the cup" with your hands, the sensor is going to read all over the map depending on where your hands are.<br /><br />If you want to discuss this more off-blog, my email is firstname@lastname.org. I'd be happy to help you get this working.<br />Dr. Ayarshttps://www.blogger.com/profile/11192509765516630383noreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-46103008470102174252012-11-14T06:02:38.551-08:002012-11-14T06:02:38.551-08:00OK as a little test I pressed the sensor to the ou...OK as a little test I pressed the sensor to the outside of the plastic cup I was using for a test and at first it worked exactly as in the cup but then I realized that the sensor was still wet and I was reading the water still on the sensor.<br /><br />So back in the water. Will the tree effect the reading? If I strap this to the trunk. will it read the trunk and not the water. <br /><br />I may have to consult my one son. I think he had to learn capacitance theory as part of the engineering physics program he is in. I think he has no knowledge of how to hook them up in a circuit just how they work at a theoretical level.Anonymoushttps://www.blogger.com/profile/02467270968136324327noreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-39697203586420397682012-11-13T18:50:36.589-08:002012-11-13T18:50:36.589-08:00Well I just used two strips of Aluminum foil and i...Well I just used two strips of Aluminum foil and it worked fine. I'll try the strips outside the stand once everything pulled won from the attic. Anonymoushttps://www.blogger.com/profile/02467270968136324327noreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-52036070302345905502012-11-10T15:07:47.029-08:002012-11-10T15:07:47.029-08:00Copper is not required, any conductor would work.
...Copper is not required, any conductor would work.<br /><br />Taping electrodes to the outside of a plastic stand just might work! That's an interesting idea, be sure to post here to let us know if it worked. Most plastics have a relatively high dielectric constant, so depending on the thickness of the stand there might not be much effect from the water... but it's certainly worth a try. Dr. Ayarshttps://www.blogger.com/profile/11192509765516630383noreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-54729530628612484092012-11-09T13:08:10.978-08:002012-11-09T13:08:10.978-08:00I've been searching for this for about a year ...I've been searching for this for about a year and finally found it again.<br /><br />Do you have to use copper (have plenty of aluminium tape and if you have a plastic tree stand would it work outside the water glued to the side of the container?Anonymoushttps://www.blogger.com/profile/02467270968136324327noreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-21985710832306678092012-03-23T06:23:43.034-07:002012-03-23T06:23:43.034-07:00I love the Morse code alert.I love the Morse code alert.coat standhttp://coatstandcoatstand.comnoreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-52598053049960303462011-12-07T13:59:13.149-08:002011-12-07T13:59:13.149-08:00Hook it to a pump instead of a led = Auto waterHook it to a pump instead of a led = Auto waterAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-38893335957684232.post-23162455142731589922011-12-07T11:03:08.017-08:002011-12-07T11:03:08.017-08:00Nice job, I love the Morse code alert. I wonder if...Nice job, I love the Morse code alert. I wonder if you could simply measure the capacitance of the whole cast iron stand and ditch the dedicated sensor?TomTheGeekhttps://www.blogger.com/profile/02075228623095552926noreply@blogger.com